Split copy.c into four files.

Copy.c has grown really large. Split it into more manageable parts:

- copy.c now contains only a few functions that are common to COPY FROM
  and COPY TO.

- copyto.c contains code for COPY TO.

- copyfrom.c contains code for initializing COPY FROM, and inserting the
  tuples to the correct table.

- copyfromparse.c contains code for reading from the client/file/program,
  and parsing the input text/CSV/binary format into tuples.

All of these parts are fairly complicated, and fairly independent of each
other. There is a patch being discussed to implement parallel COPY FROM,
which will add a lot of new code to the COPY FROM path, and another patch
which would allow INSERTs to use the same multi-insert machinery as COPY
FROM, both of which will require refactoring that code. With those two
patches, there's going to be a lot of code churn in copy.c anyway, so now
seems like a good time to do this refactoring.

The CopyStateData struct is also split. All the formatting options, like
FORMAT, QUOTE, ESCAPE, are put in a new CopyFormatOption struct, which
is used by both COPY FROM and TO. Other state data are kept in separate
CopyFromStateData and CopyToStateData structs.

Reviewed-by: Soumyadeep Chakraborty, Erik Rijkers, Vignesh C, Andres Freund
Discussion: https://www.postgresql.org/message-id/8e15b560-f387-7acc-ac90-763986617bfb%40iki.fi

contrib/file_fdw/file_fdw.c

@@ -105,7 +105,7 @@ typedef struct FileFdwExecutionState
 	bool		is_program;		/* true if filename represents an OS command */
 	List	   *options;		/* merged COPY options, excluding filename and
 								 * is_program */
-	CopyState	cstate;			/* COPY execution state */
+	CopyFromState cstate;		/* COPY execution state */
 } FileFdwExecutionState;
 
 /*
@@ -655,7 +655,7 @@ fileBeginForeignScan(ForeignScanState *node, int eflags)
 	char	   *filename;
 	bool		is_program;
 	List	   *options;
-	CopyState	cstate;
+	CopyFromState cstate;
 	FileFdwExecutionState *festate;
 
 	/*
@@ -677,6 +677,7 @@ fileBeginForeignScan(ForeignScanState *node, int eflags)
 	 */
 	cstate = BeginCopyFrom(NULL,
 						   node->ss.ss_currentRelation,
+						   NULL,
 						   filename,
 						   is_program,
 						   NULL,
@@ -752,6 +753,7 @@ fileReScanForeignScan(ForeignScanState *node)
 
 	festate->cstate = BeginCopyFrom(NULL,
 									node->ss.ss_currentRelation,
+									NULL,
 									festate->filename,
 									festate->is_program,
 									NULL,
@@ -1107,7 +1109,7 @@ file_acquire_sample_rows(Relation onerel, int elevel,
 	char	   *filename;
 	bool		is_program;
 	List	   *options;
-	CopyState	cstate;
+	CopyFromState cstate;
 	ErrorContextCallback errcallback;
 	MemoryContext oldcontext = CurrentMemoryContext;
 	MemoryContext tupcontext;
@@ -1125,7 +1127,7 @@ file_acquire_sample_rows(Relation onerel, int elevel,
 	/*
 	 * Create CopyState from FDW options.
 	 */
-	cstate = BeginCopyFrom(NULL, onerel, filename, is_program, NULL, NIL,
+	cstate = BeginCopyFrom(NULL, onerel, NULL, filename, is_program, NULL, NIL,
 						   options);
 
 	/*

src/backend/commands/Makefile

@@ -24,6 +24,9 @@ OBJS = \
 	constraint.o \
 	conversioncmds.o \
 	copy.o \
+	copyfrom.o \
+	copyfromparse.o \
+	copyto.o \
 	createas.o \
 	dbcommands.o \
 	define.o \

src/backend/commands/copyfrom.c

+/*-------------------------------------------------------------------------
+ *
+ * copyfrom.c
+ *		COPY <table> FROM file/program/client
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/copyfrom.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <ctype.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "access/heapam.h"
+#include "access/htup_details.h"
+#include "access/tableam.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "commands/copy.h"
+#include "commands/copyfrom_internal.h"
+#include "commands/trigger.h"
+#include "executor/execPartition.h"
+#include "executor/executor.h"
+#include "executor/nodeModifyTable.h"
+#include "executor/tuptable.h"
+#include "foreign/fdwapi.h"
+#include "libpq/libpq.h"
+#include "libpq/pqformat.h"
+#include "miscadmin.h"
+#include "optimizer/optimizer.h"
+#include "rewrite/rewriteHandler.h"
+#include "storage/fd.h"
+#include "tcop/tcopprot.h"
+#include "utils/lsyscache.h"
+#include "utils/memutils.h"
+#include "utils/portal.h"
+#include "utils/rel.h"
+#include "utils/snapmgr.h"
+
+/*
+ * No more than this many tuples per CopyMultiInsertBuffer
+ *
+ * Caution: Don't make this too big, as we could end up with this many
+ * CopyMultiInsertBuffer items stored in CopyMultiInsertInfo's
+ * multiInsertBuffers list.  Increasing this can cause quadratic growth in
+ * memory requirements during copies into partitioned tables with a large
+ * number of partitions.
+ */
+#define MAX_BUFFERED_TUPLES		1000
+
+/*
+ * Flush buffers if there are >= this many bytes, as counted by the input
+ * size, of tuples stored.
+ */
+#define MAX_BUFFERED_BYTES		65535
+
+/* Trim the list of buffers back down to this number after flushing */
+#define MAX_PARTITION_BUFFERS	32
+
+/* Stores multi-insert data related to a single relation in CopyFrom. */
+typedef struct CopyMultiInsertBuffer
+{
+	TupleTableSlot *slots[MAX_BUFFERED_TUPLES]; /* Array to store tuples */
+	ResultRelInfo *resultRelInfo;	/* ResultRelInfo for 'relid' */
+	BulkInsertState bistate;	/* BulkInsertState for this rel */
+	int			nused;			/* number of 'slots' containing tuples */
+	uint64		linenos[MAX_BUFFERED_TUPLES];	/* Line # of tuple in copy
+												 * stream */
+} CopyMultiInsertBuffer;
+
+/*
+ * Stores one or many CopyMultiInsertBuffers and details about the size and
+ * number of tuples which are stored in them.  This allows multiple buffers to
+ * exist at once when COPYing into a partitioned table.
+ */
+typedef struct CopyMultiInsertInfo
+{
+	List	   *multiInsertBuffers; /* List of tracked CopyMultiInsertBuffers */
+	int			bufferedTuples; /* number of tuples buffered over all buffers */
+	int			bufferedBytes;	/* number of bytes from all buffered tuples */
+	CopyFromState	cstate;			/* Copy state for this CopyMultiInsertInfo */
+	EState	   *estate;			/* Executor state used for COPY */
+	CommandId	mycid;			/* Command Id used for COPY */
+	int			ti_options;		/* table insert options */
+} CopyMultiInsertInfo;
+
+
+/* non-export function prototypes */
+static char *limit_printout_length(const char *str);
+
+static void ClosePipeFromProgram(CopyFromState cstate);
+
+/*
+ * error context callback for COPY FROM
+ *
+ * The argument for the error context must be CopyFromState.
+ */
+void
+CopyFromErrorCallback(void *arg)
+{
+	CopyFromState	cstate = (CopyFromState) arg;
+	char		curlineno_str[32];
+
+	snprintf(curlineno_str, sizeof(curlineno_str), UINT64_FORMAT,
+			 cstate->cur_lineno);
+
+	if (cstate->opts.binary)
+	{
+		/* can't usefully display the data */
+		if (cstate->cur_attname)
+			errcontext("COPY %s, line %s, column %s",
+					   cstate->cur_relname, curlineno_str,
+					   cstate->cur_attname);
+		else
+			errcontext("COPY %s, line %s",
+					   cstate->cur_relname, curlineno_str);
+	}
+	else
+	{
+		if (cstate->cur_attname && cstate->cur_attval)
+		{
+			/* error is relevant to a particular column */
+			char	   *attval;
+
+			attval = limit_printout_length(cstate->cur_attval);
+			errcontext("COPY %s, line %s, column %s: \"%s\"",
+					   cstate->cur_relname, curlineno_str,
+					   cstate->cur_attname, attval);
+			pfree(attval);
+		}
+		else if (cstate->cur_attname)
+		{
+			/* error is relevant to a particular column, value is NULL */
+			errcontext("COPY %s, line %s, column %s: null input",
+					   cstate->cur_relname, curlineno_str,
+					   cstate->cur_attname);
+		}
+		else
+		{
+			/*
+			 * Error is relevant to a particular line.
+			 *
+			 * If line_buf still contains the correct line, and it's already
+			 * transcoded, print it. If it's still in a foreign encoding, it's
+			 * quite likely that the error is precisely a failure to do
+			 * encoding conversion (ie, bad data). We dare not try to convert
+			 * it, and at present there's no way to regurgitate it without
+			 * conversion. So we have to punt and just report the line number.
+			 */
+			if (cstate->line_buf_valid &&
+				(cstate->line_buf_converted || !cstate->need_transcoding))
+			{
+				char	   *lineval;
+
+				lineval = limit_printout_length(cstate->line_buf.data);
+				errcontext("COPY %s, line %s: \"%s\"",
+						   cstate->cur_relname, curlineno_str, lineval);
+				pfree(lineval);
+			}
+			else
+			{
+				errcontext("COPY %s, line %s",
+						   cstate->cur_relname, curlineno_str);
+			}
+		}
+	}
+}
+
+/*
+ * Make sure we don't print an unreasonable amount of COPY data in a message.
+ *
+ * Returns a pstrdup'd copy of the input.
+ */
+static char *
+limit_printout_length(const char *str)
+{
+#define MAX_COPY_DATA_DISPLAY 100
+
+	int			slen = strlen(str);
+	int			len;
+	char	   *res;
+
+	/* Fast path if definitely okay */
+	if (slen <= MAX_COPY_DATA_DISPLAY)
+		return pstrdup(str);
+
+	/* Apply encoding-dependent truncation */
+	len = pg_mbcliplen(str, slen, MAX_COPY_DATA_DISPLAY);
+
+	/*
+	 * Truncate, and add "..." to show we truncated the input.
+	 */
+	res = (char *) palloc(len + 4);
+	memcpy(res, str, len);
+	strcpy(res + len, "...");
+
+	return res;
+}
+
+/*
+ * Allocate memory and initialize a new CopyMultiInsertBuffer for this
+ * ResultRelInfo.
+ */
+static CopyMultiInsertBuffer *
+CopyMultiInsertBufferInit(ResultRelInfo *rri)
+{
+	CopyMultiInsertBuffer *buffer;
+
+	buffer = (CopyMultiInsertBuffer *) palloc(sizeof(CopyMultiInsertBuffer));
+	memset(buffer->slots, 0, sizeof(TupleTableSlot *) * MAX_BUFFERED_TUPLES);
+	buffer->resultRelInfo = rri;
+	buffer->bistate = GetBulkInsertState();
+	buffer->nused = 0;
+
+	return buffer;
+}
+
+/*
+ * Make a new buffer for this ResultRelInfo.
+ */
+static inline void
+CopyMultiInsertInfoSetupBuffer(CopyMultiInsertInfo *miinfo,
+							   ResultRelInfo *rri)
+{
+	CopyMultiInsertBuffer *buffer;
+
+	buffer = CopyMultiInsertBufferInit(rri);
+
+	/* Setup back-link so we can easily find this buffer again */
+	rri->ri_CopyMultiInsertBuffer = buffer;
+	/* Record that we're tracking this buffer */
+	miinfo->multiInsertBuffers = lappend(miinfo->multiInsertBuffers, buffer);
+}
+
+/*
+ * Initialize an already allocated CopyMultiInsertInfo.
+ *
+ * If rri is a non-partitioned table then a CopyMultiInsertBuffer is set up
+ * for that table.
+ */
+static void
+CopyMultiInsertInfoInit(CopyMultiInsertInfo *miinfo, ResultRelInfo *rri,
+						CopyFromState cstate, EState *estate, CommandId mycid,
+						int ti_options)
+{
+	miinfo->multiInsertBuffers = NIL;
+	miinfo->bufferedTuples = 0;
+	miinfo->bufferedBytes = 0;
+	miinfo->cstate = cstate;
+	miinfo->estate = estate;
+	miinfo->mycid = mycid;
+	miinfo->ti_options = ti_options;
+
+	/*
+	 * Only setup the buffer when not dealing with a partitioned table.
+	 * Buffers for partitioned tables will just be setup when we need to send
+	 * tuples their way for the first time.
+	 */
+	if (rri->ri_RelationDesc->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		CopyMultiInsertInfoSetupBuffer(miinfo, rri);
+}
+
+/*
+ * Returns true if the buffers are full
+ */
+static inline bool
+CopyMultiInsertInfoIsFull(CopyMultiInsertInfo *miinfo)
+{
+	if (miinfo->bufferedTuples >= MAX_BUFFERED_TUPLES ||
+		miinfo->bufferedBytes >= MAX_BUFFERED_BYTES)
+		return true;
+	return false;
+}
+
+/*
+ * Returns true if we have no buffered tuples
+ */
+static inline bool
+CopyMultiInsertInfoIsEmpty(CopyMultiInsertInfo *miinfo)
+{
+	return miinfo->bufferedTuples == 0;
+}
+
+/*
+ * Write the tuples stored in 'buffer' out to the table.
+ */
+static inline void
+CopyMultiInsertBufferFlush(CopyMultiInsertInfo *miinfo,
+						   CopyMultiInsertBuffer *buffer)
+{
+	MemoryContext oldcontext;
+	int			i;
+	uint64		save_cur_lineno;
+	CopyFromState	cstate = miinfo->cstate;
+	EState	   *estate = miinfo->estate;
+	CommandId	mycid = miinfo->mycid;
+	int			ti_options = miinfo->ti_options;
+	bool		line_buf_valid = cstate->line_buf_valid;
+	int			nused = buffer->nused;
+	ResultRelInfo *resultRelInfo = buffer->resultRelInfo;
+	TupleTableSlot **slots = buffer->slots;
+
+	/*
+	 * Print error context information correctly, if one of the operations
+	 * below fail.
+	 */
+	cstate->line_buf_valid = false;
+	save_cur_lineno = cstate->cur_lineno;
+
+	/*
+	 * table_multi_insert may leak memory, so switch to short-lived memory
+	 * context before calling it.
+	 */
+	oldcontext = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
+	table_multi_insert(resultRelInfo->ri_RelationDesc,
+					   slots,
+					   nused,
+					   mycid,
+					   ti_options,
+					   buffer->bistate);
+	MemoryContextSwitchTo(oldcontext);
+
+	for (i = 0; i < nused; i++)
+	{
+		/*
+		 * If there are any indexes, update them for all the inserted tuples,
+		 * and run AFTER ROW INSERT triggers.
+		 */
+		if (resultRelInfo->ri_NumIndices > 0)
+		{
+			List	   *recheckIndexes;
+
+			cstate->cur_lineno = buffer->linenos[i];
+			recheckIndexes =
+				ExecInsertIndexTuples(resultRelInfo,
+									  buffer->slots[i], estate, false, NULL,
+									  NIL);
+			ExecARInsertTriggers(estate, resultRelInfo,
+								 slots[i], recheckIndexes,
+								 cstate->transition_capture);
+			list_free(recheckIndexes);
+		}
+
+		/*
+		 * There's no indexes, but see if we need to run AFTER ROW INSERT
+		 * triggers anyway.
+		 */
+		else if (resultRelInfo->ri_TrigDesc != NULL &&
+				 (resultRelInfo->ri_TrigDesc->trig_insert_after_row ||
+				  resultRelInfo->ri_TrigDesc->trig_insert_new_table))
+		{
+			cstate->cur_lineno = buffer->linenos[i];
+			ExecARInsertTriggers(estate, resultRelInfo,
+								 slots[i], NIL, cstate->transition_capture);
+		}
+
+		ExecClearTuple(slots[i]);
+	}
+
+	/* Mark that all slots are free */
+	buffer->nused = 0;
+
+	/* reset cur_lineno and line_buf_valid to what they were */
+	cstate->line_buf_valid = line_buf_valid;
+	cstate->cur_lineno = save_cur_lineno;
+}
+
+/*
+ * Drop used slots and free member for this buffer.
+ *
+ * The buffer must be flushed before cleanup.
+ */
+static inline void
+CopyMultiInsertBufferCleanup(CopyMultiInsertInfo *miinfo,
+							 CopyMultiInsertBuffer *buffer)
+{
+	int			i;
+
+	/* Ensure buffer was flushed */
+	Assert(buffer->nused == 0);
+
+	/* Remove back-link to ourself */
+	buffer->resultRelInfo->ri_CopyMultiInsertBuffer = NULL;
+
+	FreeBulkInsertState(buffer->bistate);
+
+	/* Since we only create slots on demand, just drop the non-null ones. */
+	for (i = 0; i < MAX_BUFFERED_TUPLES && buffer->slots[i] != NULL; i++)
+		ExecDropSingleTupleTableSlot(buffer->slots[i]);
+
+	table_finish_bulk_insert(buffer->resultRelInfo->ri_RelationDesc,
+							 miinfo->ti_options);
+
+	pfree(buffer);
+}
+
+/*
+ * Write out all stored tuples in all buffers out to the tables.
+ *
+ * Once flushed we also trim the tracked buffers list down to size by removing
+ * the buffers created earliest first.
+ *
+ * Callers should pass 'curr_rri' is the ResultRelInfo that's currently being
+ * used.  When cleaning up old buffers we'll never remove the one for
+ * 'curr_rri'.
+ */
+static inline void
+CopyMultiInsertInfoFlush(CopyMultiInsertInfo *miinfo, ResultRelInfo *curr_rri)
+{
+	ListCell   *lc;
+
+	foreach(lc, miinfo->multiInsertBuffers)
+	{
+		CopyMultiInsertBuffer *buffer = (CopyMultiInsertBuffer *) lfirst(lc);
+
+		CopyMultiInsertBufferFlush(miinfo, buffer);
+	}
+
+	miinfo->bufferedTuples = 0;
+	miinfo->bufferedBytes = 0;
+
+	/*
+	 * Trim the list of tracked buffers down if it exceeds the limit.  Here we
+	 * remove buffers starting with the ones we created first.  It seems less
+	 * likely that these older ones will be needed than the ones that were
+	 * just created.
+	 */
+	while (list_length(miinfo->multiInsertBuffers) > MAX_PARTITION_BUFFERS)
+	{
+		CopyMultiInsertBuffer *buffer;
+
+		buffer = (CopyMultiInsertBuffer *) linitial(miinfo->multiInsertBuffers);
+
+		/*
+		 * We never want to remove the buffer that's currently being used, so
+		 * if we happen to find that then move it to the end of the list.
+		 */
+		if (buffer->resultRelInfo == curr_rri)
+		{
+			miinfo->multiInsertBuffers = list_delete_first(miinfo->multiInsertBuffers);
+			miinfo->multiInsertBuffers = lappend(miinfo->multiInsertBuffers, buffer);
+			buffer = (CopyMultiInsertBuffer *) linitial(miinfo->multiInsertBuffers);
+		}
+
+		CopyMultiInsertBufferCleanup(miinfo, buffer);
+		miinfo->multiInsertBuffers = list_delete_first(miinfo->multiInsertBuffers);
+	}
+}
+
+/*
+ * Cleanup allocated buffers and free memory
+ */
+static inline void
+CopyMultiInsertInfoCleanup(CopyMultiInsertInfo *miinfo)
+{
+	ListCell   *lc;
+
+	foreach(lc, miinfo->multiInsertBuffers)
+		CopyMultiInsertBufferCleanup(miinfo, lfirst(lc));
+
+	list_free(miinfo->multiInsertBuffers);
+}
+
+/*
+ * Get the next TupleTableSlot that the next tuple should be stored in.
+ *
+ * Callers must ensure that the buffer is not full.
+ *
+ * Note: 'miinfo' is unused but has been included for consistency with the
+ * other functions in this area.
+ */
+static inline TupleTableSlot *
+CopyMultiInsertInfoNextFreeSlot(CopyMultiInsertInfo *miinfo,
+								ResultRelInfo *rri)
+{
+	CopyMultiInsertBuffer *buffer = rri->ri_CopyMultiInsertBuffer;
+	int			nused = buffer->nused;
+
+	Assert(buffer != NULL);
+	Assert(nused < MAX_BUFFERED_TUPLES);
+
+	if (buffer->slots[nused] == NULL)
+		buffer->slots[nused] = table_slot_create(rri->ri_RelationDesc, NULL);
+	return buffer->slots[nused];
+}
+
+/*
+ * Record the previously reserved TupleTableSlot that was reserved by
+ * CopyMultiInsertInfoNextFreeSlot as being consumed.
+ */
+static inline void
+CopyMultiInsertInfoStore(CopyMultiInsertInfo *miinfo, ResultRelInfo *rri,
+						 TupleTableSlot *slot, int tuplen, uint64 lineno)
+{
+	CopyMultiInsertBuffer *buffer = rri->ri_CopyMultiInsertBuffer;
+
+	Assert(buffer != NULL);
+	Assert(slot == buffer->slots[buffer->nused]);
+
+	/* Store the line number so we can properly report any errors later */
+	buffer->linenos[buffer->nused] = lineno;
+
+	/* Record this slot as being used */
+	buffer->nused++;
+
+	/* Update how many tuples are stored and their size */
+	miinfo->bufferedTuples++;
+	miinfo->bufferedBytes += tuplen;
+}
+
+/*
+ * Copy FROM file to relation.
+ */
+uint64
+CopyFrom(CopyFromState cstate)
+{
+	ResultRelInfo *resultRelInfo;
+	ResultRelInfo *target_resultRelInfo;
+	ResultRelInfo *prevResultRelInfo = NULL;
+	EState	   *estate = CreateExecutorState(); /* for ExecConstraints() */
+	ModifyTableState *mtstate;
+	ExprContext *econtext;
+	TupleTableSlot *singleslot = NULL;
+	MemoryContext oldcontext = CurrentMemoryContext;
+
+	PartitionTupleRouting *proute = NULL;
+	ErrorContextCallback errcallback;
+	CommandId	mycid = GetCurrentCommandId(true);
+	int			ti_options = 0; /* start with default options for insert */
+	BulkInsertState bistate = NULL;
+	CopyInsertMethod insertMethod;
+	CopyMultiInsertInfo multiInsertInfo = {0};	/* pacify compiler */
+	uint64		processed = 0;
+	bool		has_before_insert_row_trig;
+	bool		has_instead_insert_row_trig;
+	bool		leafpart_use_multi_insert = false;
+
+	Assert(cstate->rel);
+	Assert(list_length(cstate->range_table) == 1);
+
+	/*
+	 * The target must be a plain, foreign, or partitioned relation, or have
+	 * an INSTEAD OF INSERT row trigger.  (Currently, such triggers are only
+	 * allowed on views, so we only hint about them in the view case.)
+	 */
+	if (cstate->rel->rd_rel->relkind != RELKIND_RELATION &&
+		cstate->rel->rd_rel->relkind != RELKIND_FOREIGN_TABLE &&
+		cstate->rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE &&
+		!(cstate->rel->trigdesc &&
+		  cstate->rel->trigdesc->trig_insert_instead_row))
+	{
+		if (cstate->rel->rd_rel->relkind == RELKIND_VIEW)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy to view \"%s\"",
+							RelationGetRelationName(cstate->rel)),
+					 errhint("To enable copying to a view, provide an INSTEAD OF INSERT trigger.")));
+		else if (cstate->rel->rd_rel->relkind == RELKIND_MATVIEW)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy to materialized view \"%s\"",
+							RelationGetRelationName(cstate->rel))));
+		else if (cstate->rel->rd_rel->relkind == RELKIND_SEQUENCE)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy to sequence \"%s\"",
+							RelationGetRelationName(cstate->rel))));
+		else
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy to non-table relation \"%s\"",
+							RelationGetRelationName(cstate->rel))));
+	}
+
+	/*
+	 * If the target file is new-in-transaction, we assume that checking FSM
+	 * for free space is a waste of time.  This could possibly be wrong, but
+	 * it's unlikely.
+	 */
+	if (RELKIND_HAS_STORAGE(cstate->rel->rd_rel->relkind) &&
+		(cstate->rel->rd_createSubid != InvalidSubTransactionId ||
+		 cstate->rel->rd_firstRelfilenodeSubid != InvalidSubTransactionId))
+		ti_options |= TABLE_INSERT_SKIP_FSM;
+
+	/*
+	 * Optimize if new relfilenode was created in this subxact or one of its
+	 * committed children and we won't see those rows later as part of an
+	 * earlier scan or command. The subxact test ensures that if this subxact
+	 * aborts then the frozen rows won't be visible after xact cleanup.  Note
+	 * that the stronger test of exactly which subtransaction created it is
+	 * crucial for correctness of this optimization. The test for an earlier
+	 * scan or command tolerates false negatives. FREEZE causes other sessions
+	 * to see rows they would not see under MVCC, and a false negative merely
+	 * spreads that anomaly to the current session.
+	 */
+	if (cstate->opts.freeze)
+	{
+		/*
+		 * We currently disallow COPY FREEZE on partitioned tables.  The
+		 * reason for this is that we've simply not yet opened the partitions
+		 * to determine if the optimization can be applied to them.  We could
+		 * go and open them all here, but doing so may be quite a costly
+		 * overhead for small copies.  In any case, we may just end up routing
+		 * tuples to a small number of partitions.  It seems better just to
+		 * raise an ERROR for partitioned tables.
+		 */
+		if (cstate->rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("cannot perform COPY FREEZE on a partitioned table")));
+		}
+
+		/*
+		 * Tolerate one registration for the benefit of FirstXactSnapshot.
+		 * Scan-bearing queries generally create at least two registrations,
+		 * though relying on that is fragile, as is ignoring ActiveSnapshot.
+		 * Clear CatalogSnapshot to avoid counting its registration.  We'll
+		 * still detect ongoing catalog scans, each of which separately
+		 * registers the snapshot it uses.
+		 */
+		InvalidateCatalogSnapshot();
+		if (!ThereAreNoPriorRegisteredSnapshots() || !ThereAreNoReadyPortals())
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
+					 errmsg("cannot perform COPY FREEZE because of prior transaction activity")));
+
+		if (cstate->rel->rd_createSubid != GetCurrentSubTransactionId() &&
+			cstate->rel->rd_newRelfilenodeSubid != GetCurrentSubTransactionId())
+			ereport(ERROR,
+					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					 errmsg("cannot perform COPY FREEZE because the table was not created or truncated in the current subtransaction")));
+
+		ti_options |= TABLE_INSERT_FROZEN;
+	}
+
+	/*
+	 * We need a ResultRelInfo so we can use the regular executor's
+	 * index-entry-making machinery.  (There used to be a huge amount of code
+	 * here that basically duplicated execUtils.c ...)
+	 */
+	ExecInitRangeTable(estate, cstate->range_table);
+	resultRelInfo = target_resultRelInfo = makeNode(ResultRelInfo);
+	ExecInitResultRelation(estate, resultRelInfo, 1);
+
+	/* Verify the named relation is a valid target for INSERT */
+	CheckValidResultRel(resultRelInfo, CMD_INSERT);
+
+	ExecOpenIndices(resultRelInfo, false);
+
+	/*
+	 * Set up a ModifyTableState so we can let FDW(s) init themselves for
+	 * foreign-table result relation(s).
+	 */
+	mtstate = makeNode(ModifyTableState);
+	mtstate->ps.plan = NULL;
+	mtstate->ps.state = estate;
+	mtstate->operation = CMD_INSERT;
+	mtstate->resultRelInfo = resultRelInfo;
+
+	if (resultRelInfo->ri_FdwRoutine != NULL &&
+		resultRelInfo->ri_FdwRoutine->BeginForeignInsert != NULL)
+		resultRelInfo->ri_FdwRoutine->BeginForeignInsert(mtstate,
+														 resultRelInfo);
+
+	/* Prepare to catch AFTER triggers. */
+	AfterTriggerBeginQuery();
+
+	/*
+	 * If there are any triggers with transition tables on the named relation,
+	 * we need to be prepared to capture transition tuples.
+	 *
+	 * Because partition tuple routing would like to know about whether
+	 * transition capture is active, we also set it in mtstate, which is
+	 * passed to ExecFindPartition() below.
+	 */
+	cstate->transition_capture = mtstate->mt_transition_capture =
+		MakeTransitionCaptureState(cstate->rel->trigdesc,
+								   RelationGetRelid(cstate->rel),
+								   CMD_INSERT);
+
+	/*
+	 * If the named relation is a partitioned table, initialize state for
+	 * CopyFrom tuple routing.
+	 */
+	if (cstate->rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+		proute = ExecSetupPartitionTupleRouting(estate, NULL, cstate->rel);
+
+	if (cstate->whereClause)
+		cstate->qualexpr = ExecInitQual(castNode(List, cstate->whereClause),
+										&mtstate->ps);
+
+	/*
+	 * It's generally more efficient to prepare a bunch of tuples for
+	 * insertion, and insert them in one table_multi_insert() call, than call
+	 * table_tuple_insert() separately for every tuple. However, there are a
+	 * number of reasons why we might not be able to do this.  These are
+	 * explained below.
+	 */
+	if (resultRelInfo->ri_TrigDesc != NULL &&
+		(resultRelInfo->ri_TrigDesc->trig_insert_before_row ||
+		 resultRelInfo->ri_TrigDesc->trig_insert_instead_row))
+	{
+		/*
+		 * Can't support multi-inserts when there are any BEFORE/INSTEAD OF
+		 * triggers on the table. Such triggers might query the table we're
+		 * inserting into and act differently if the tuples that have already
+		 * been processed and prepared for insertion are not there.
+		 */
+		insertMethod = CIM_SINGLE;
+	}
+	else if (proute != NULL && resultRelInfo->ri_TrigDesc != NULL &&
+			 resultRelInfo->ri_TrigDesc->trig_insert_new_table)
+	{
+		/*
+		 * For partitioned tables we can't support multi-inserts when there
+		 * are any statement level insert triggers. It might be possible to
+		 * allow partitioned tables with such triggers in the future, but for
+		 * now, CopyMultiInsertInfoFlush expects that any before row insert
+		 * and statement level insert triggers are on the same relation.
+		 */
+		insertMethod = CIM_SINGLE;
+	}
+	else if (resultRelInfo->ri_FdwRoutine != NULL ||
+			 cstate->volatile_defexprs)
+	{
+		/*
+		 * Can't support multi-inserts to foreign tables or if there are any
+		 * volatile default expressions in the table.  Similarly to the
+		 * trigger case above, such expressions may query the table we're
+		 * inserting into.
+		 *
+		 * Note: It does not matter if any partitions have any volatile
+		 * default expressions as we use the defaults from the target of the
+		 * COPY command.
+		 */
+		insertMethod = CIM_SINGLE;
+	}
+	else if (contain_volatile_functions(cstate->whereClause))
+	{
+		/*
+		 * Can't support multi-inserts if there are any volatile function
+		 * expressions in WHERE clause.  Similarly to the trigger case above,
+		 * such expressions may query the table we're inserting into.
+		 */
+		insertMethod = CIM_SINGLE;
+	}
+	else
+	{
+		/*
+		 * For partitioned tables, we may still be able to perform bulk
+		 * inserts.  However, the possibility of this depends on which types
+		 * of triggers exist on the partition.  We must disable bulk inserts
+		 * if the partition is a foreign table or it has any before row insert
+		 * or insert instead triggers (same as we checked above for the parent
+		 * table).  Since the partition's resultRelInfos are initialized only
+		 * when we actually need to insert the first tuple into them, we must
+		 * have the intermediate insert method of CIM_MULTI_CONDITIONAL to
+		 * flag that we must later determine if we can use bulk-inserts for
+		 * the partition being inserted into.
+		 */
+		if (proute)
+			insertMethod = CIM_MULTI_CONDITIONAL;
+		else
+			insertMethod = CIM_MULTI;
+
+		CopyMultiInsertInfoInit(&multiInsertInfo, resultRelInfo, cstate,
+								estate, mycid, ti_options);
+	}
+
+	/*
+	 * If not using batch mode (which allocates slots as needed) set up a
+	 * tuple slot too. When inserting into a partitioned table, we also need
+	 * one, even if we might batch insert, to read the tuple in the root
+	 * partition's form.
+	 */
+	if (insertMethod == CIM_SINGLE || insertMethod == CIM_MULTI_CONDITIONAL)
+	{
+		singleslot = table_slot_create(resultRelInfo->ri_RelationDesc,
+									   &estate->es_tupleTable);
+		bistate = GetBulkInsertState();
+	}
+
+	has_before_insert_row_trig = (resultRelInfo->ri_TrigDesc &&
+								  resultRelInfo->ri_TrigDesc->trig_insert_before_row);
+
+	has_instead_insert_row_trig = (resultRelInfo->ri_TrigDesc &&
+								   resultRelInfo->ri_TrigDesc->trig_insert_instead_row);
+
+	/*
+	 * Check BEFORE STATEMENT insertion triggers. It's debatable whether we
+	 * should do this for COPY, since it's not really an "INSERT" statement as
+	 * such. However, executing these triggers maintains consistency with the
+	 * EACH ROW triggers that we already fire on COPY.
+	 */
+	ExecBSInsertTriggers(estate, resultRelInfo);
+
+	econtext = GetPerTupleExprContext(estate);
+
+	/* Set up callback to identify error line number */
+	errcallback.callback = CopyFromErrorCallback;
+	errcallback.arg = (void *) cstate;
+	errcallback.previous = error_context_stack;
+	error_context_stack = &errcallback;
+
+	for (;;)
+	{
+		TupleTableSlot *myslot;
+		bool		skip_tuple;
+
+		CHECK_FOR_INTERRUPTS();
+
+		/*
+		 * Reset the per-tuple exprcontext. We do this after every tuple, to
+		 * clean-up after expression evaluations etc.
+		 */
+		ResetPerTupleExprContext(estate);
+
+		/* select slot to (initially) load row into */
+		if (insertMethod == CIM_SINGLE || proute)
+		{
+			myslot = singleslot;
+			Assert(myslot != NULL);
+		}
+		else
+		{
+			Assert(resultRelInfo == target_resultRelInfo);
+			Assert(insertMethod == CIM_MULTI);
+
+			myslot = CopyMultiInsertInfoNextFreeSlot(&multiInsertInfo,
+													 resultRelInfo);
+		}
+
+		/*
+		 * Switch to per-tuple context before calling NextCopyFrom, which does
+		 * evaluate default expressions etc. and requires per-tuple context.
+		 */
+		MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
+
+		ExecClearTuple(myslot);
+
+		/* Directly store the values/nulls array in the slot */
+		if (!NextCopyFrom(cstate, econtext, myslot->tts_values, myslot->tts_isnull))
+			break;
+
+		ExecStoreVirtualTuple(myslot);
+
+		/*
+		 * Constraints and where clause might reference the tableoid column,
+		 * so (re-)initialize tts_tableOid before evaluating them.
+		 */
+		myslot->tts_tableOid = RelationGetRelid(target_resultRelInfo->ri_RelationDesc);
+
+		/* Triggers and stuff need to be invoked in query context. */
+		MemoryContextSwitchTo(oldcontext);
+
+		if (cstate->whereClause)
+		{
+			econtext->ecxt_scantuple = myslot;
+			/* Skip items that don't match COPY's WHERE clause */
+			if (!ExecQual(cstate->qualexpr, econtext))
+				continue;
+		}
+
+		/* Determine the partition to insert the tuple into */
+		if (proute)
+		{
+			TupleConversionMap *map;
+
+			/*
+			 * Attempt to find a partition suitable for this tuple.
+			 * ExecFindPartition() will raise an error if none can be found or
+			 * if the found partition is not suitable for INSERTs.
+			 */
+			resultRelInfo = ExecFindPartition(mtstate, target_resultRelInfo,
+											  proute, myslot, estate);
+
+			if (prevResultRelInfo != resultRelInfo)
+			{
+				/* Determine which triggers exist on this partition */
+				has_before_insert_row_trig = (resultRelInfo->ri_TrigDesc &&
+											  resultRelInfo->ri_TrigDesc->trig_insert_before_row);
+
+				has_instead_insert_row_trig = (resultRelInfo->ri_TrigDesc &&
+											   resultRelInfo->ri_TrigDesc->trig_insert_instead_row);
+
+				/*
+				 * Disable multi-inserts when the partition has BEFORE/INSTEAD
+				 * OF triggers, or if the partition is a foreign partition.
+				 */
+				leafpart_use_multi_insert = insertMethod == CIM_MULTI_CONDITIONAL &&
+					!has_before_insert_row_trig &&
+					!has_instead_insert_row_trig &&
+					resultRelInfo->ri_FdwRoutine == NULL;
+
+				/* Set the multi-insert buffer to use for this partition. */
+				if (leafpart_use_multi_insert)
+				{
+					if (resultRelInfo->ri_CopyMultiInsertBuffer == NULL)
+						CopyMultiInsertInfoSetupBuffer(&multiInsertInfo,
+													   resultRelInfo);
+				}
+				else if (insertMethod == CIM_MULTI_CONDITIONAL &&
+						 !CopyMultiInsertInfoIsEmpty(&multiInsertInfo))
+				{
+					/*
+					 * Flush pending inserts if this partition can't use
+					 * batching, so rows are visible to triggers etc.
+					 */
+					CopyMultiInsertInfoFlush(&multiInsertInfo, resultRelInfo);
+				}
+
+				if (bistate != NULL)
+					ReleaseBulkInsertStatePin(bistate);
+				prevResultRelInfo = resultRelInfo;
+			}
+
+			/*
+			 * If we're capturing transition tuples, we might need to convert
+			 * from the partition rowtype to root rowtype. But if there are no
+			 * BEFORE triggers on the partition that could change the tuple,
+			 * we can just remember the original unconverted tuple to avoid a
+			 * needless round trip conversion.
+			 */
+			if (cstate->transition_capture != NULL)
+				cstate->transition_capture->tcs_original_insert_tuple =
+					!has_before_insert_row_trig ? myslot : NULL;
+
+			/*
+			 * We might need to convert from the root rowtype to the partition
+			 * rowtype.
+			 */
+			map = resultRelInfo->ri_RootToPartitionMap;
+			if (insertMethod == CIM_SINGLE || !leafpart_use_multi_insert)
+			{
+				/* non batch insert */
+				if (map != NULL)
+				{
+					TupleTableSlot *new_slot;
+
+					new_slot = resultRelInfo->ri_PartitionTupleSlot;
+					myslot = execute_attr_map_slot(map->attrMap, myslot, new_slot);
+				}
+			}
+			else
+			{
+				/*
+				 * Prepare to queue up tuple for later batch insert into
+				 * current partition.
+				 */
+				TupleTableSlot *batchslot;
+
+				/* no other path available for partitioned table */
+				Assert(insertMethod == CIM_MULTI_CONDITIONAL);
+
+				batchslot = CopyMultiInsertInfoNextFreeSlot(&multiInsertInfo,
+															resultRelInfo);
+
+				if (map != NULL)
+					myslot = execute_attr_map_slot(map->attrMap, myslot,
+												   batchslot);
+				else
+				{
+					/*
+					 * This looks more expensive than it is (Believe me, I
+					 * optimized it away. Twice.). The input is in virtual
+					 * form, and we'll materialize the slot below - for most
+					 * slot types the copy performs the work materialization
+					 * would later require anyway.
+					 */
+					ExecCopySlot(batchslot, myslot);
+					myslot = batchslot;
+				}
+			}
+
+			/* ensure that triggers etc see the right relation  */
+			myslot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
+		}
+
+		skip_tuple = false;
+
+		/* BEFORE ROW INSERT Triggers */
+		if (has_before_insert_row_trig)
+		{
+			if (!ExecBRInsertTriggers(estate, resultRelInfo, myslot))
+				skip_tuple = true;	/* "do nothing" */
+		}
+
+		if (!skip_tuple)
+		{
+			/*
+			 * If there is an INSTEAD OF INSERT ROW trigger, let it handle the
+			 * tuple.  Otherwise, proceed with inserting the tuple into the
+			 * table or foreign table.
+			 */
+			if (has_instead_insert_row_trig)
+			{
+				ExecIRInsertTriggers(estate, resultRelInfo, myslot);
+			}
+			else
+			{
+				/* Compute stored generated columns */
+				if (resultRelInfo->ri_RelationDesc->rd_att->constr &&
+					resultRelInfo->ri_RelationDesc->rd_att->constr->has_generated_stored)
+					ExecComputeStoredGenerated(resultRelInfo, estate, myslot,
+											   CMD_INSERT);
+
+				/*
+				 * If the target is a plain table, check the constraints of
+				 * the tuple.
+				 */
+				if (resultRelInfo->ri_FdwRoutine == NULL &&
+					resultRelInfo->ri_RelationDesc->rd_att->constr)
+					ExecConstraints(resultRelInfo, myslot, estate);
+
+				/*
+				 * Also check the tuple against the partition constraint, if
+				 * there is one; except that if we got here via tuple-routing,
+				 * we don't need to if there's no BR trigger defined on the
+				 * partition.
+				 */
+				if (resultRelInfo->ri_RelationDesc->rd_rel->relispartition &&
+					(proute == NULL || has_before_insert_row_trig))
+					ExecPartitionCheck(resultRelInfo, myslot, estate, true);
+
+				/* Store the slot in the multi-insert buffer, when enabled. */
+				if (insertMethod == CIM_MULTI || leafpart_use_multi_insert)
+				{
+					/*
+					 * The slot previously might point into the per-tuple
+					 * context. For batching it needs to be longer lived.
+					 */
+					ExecMaterializeSlot(myslot);
+
+					/* Add this tuple to the tuple buffer */
+					CopyMultiInsertInfoStore(&multiInsertInfo,
+											 resultRelInfo, myslot,
+											 cstate->line_buf.len,
+											 cstate->cur_lineno);
+
+					/*
+					 * If enough inserts have queued up, then flush all
+					 * buffers out to their tables.
+					 */
+					if (CopyMultiInsertInfoIsFull(&multiInsertInfo))
+						CopyMultiInsertInfoFlush(&multiInsertInfo, resultRelInfo);
+				}
+				else
+				{
+					List	   *recheckIndexes = NIL;
+
+					/* OK, store the tuple */
+					if (resultRelInfo->ri_FdwRoutine != NULL)
+					{
+						myslot = resultRelInfo->ri_FdwRoutine->ExecForeignInsert(estate,
+																				 resultRelInfo,
+																				 myslot,
+																				 NULL);
+
+						if (myslot == NULL) /* "do nothing" */
+							continue;	/* next tuple please */
+
+						/*
+						 * AFTER ROW Triggers might reference the tableoid
+						 * column, so (re-)initialize tts_tableOid before
+						 * evaluating them.
+						 */
+						myslot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
+					}
+					else
+					{
+						/* OK, store the tuple and create index entries for it */
+						table_tuple_insert(resultRelInfo->ri_RelationDesc,
+										   myslot, mycid, ti_options, bistate);
+
+						if (resultRelInfo->ri_NumIndices > 0)
+							recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
+																   myslot,
+																   estate,
+																   false,
+																   NULL,
+																   NIL);
+					}
+
+					/* AFTER ROW INSERT Triggers */
+					ExecARInsertTriggers(estate, resultRelInfo, myslot,
+										 recheckIndexes, cstate->transition_capture);
+
+					list_free(recheckIndexes);
+				}
+			}
+
+			/*
+			 * We count only tuples not suppressed by a BEFORE INSERT trigger
+			 * or FDW; this is the same definition used by nodeModifyTable.c
+			 * for counting tuples inserted by an INSERT command.
+			 */
+			processed++;
+		}
+	}
+
+	/* Flush any remaining buffered tuples */
+	if (insertMethod != CIM_SINGLE)
+	{
+		if (!CopyMultiInsertInfoIsEmpty(&multiInsertInfo))
+			CopyMultiInsertInfoFlush(&multiInsertInfo, NULL);
+	}
+
+	/* Done, clean up */
+	error_context_stack = errcallback.previous;
+
+	if (bistate != NULL)
+		FreeBulkInsertState(bistate);
+
+	MemoryContextSwitchTo(oldcontext);
+
+	/*
+	 * In the old protocol, tell pqcomm that we can process normal protocol
+	 * messages again.
+	 */
+	if (cstate->copy_src == COPY_OLD_FE)
+		pq_endmsgread();
+
+	/* Execute AFTER STATEMENT insertion triggers */
+	ExecASInsertTriggers(estate, target_resultRelInfo, cstate->transition_capture);
+
+	/* Handle queued AFTER triggers */
+	AfterTriggerEndQuery(estate);
+
+	ExecResetTupleTable(estate->es_tupleTable, false);
+
+	/* Allow the FDW to shut down */
+	if (target_resultRelInfo->ri_FdwRoutine != NULL &&
+		target_resultRelInfo->ri_FdwRoutine->EndForeignInsert != NULL)
+		target_resultRelInfo->ri_FdwRoutine->EndForeignInsert(estate,
+															  target_resultRelInfo);
+
+	/* Tear down the multi-insert buffer data */
+	if (insertMethod != CIM_SINGLE)
+		CopyMultiInsertInfoCleanup(&multiInsertInfo);
+
+	/* Close all the partitioned tables, leaf partitions, and their indices */
+	if (proute)
+		ExecCleanupTupleRouting(mtstate, proute);
+
+	/* Close the result relations, including any trigger target relations */
+	ExecCloseResultRelations(estate);
+	ExecCloseRangeTableRelations(estate);
+
+	FreeExecutorState(estate);
+
+	return processed;
+}
+
+/*
+ * Setup to read tuples from a file for COPY FROM.
+ *
+ * 'rel': Used as a template for the tuples
+ * 'whereClause': WHERE clause from the COPY FROM command
+ * 'filename': Name of server-local file to read, NULL for STDIN
+ * 'is_program': true if 'filename' is program to execute
+ * 'data_source_cb': callback that provides the input data
+ * 'attnamelist': List of char *, columns to include. NIL selects all cols.
+ * 'options': List of DefElem. See copy_opt_item in gram.y for selections.
+ *
+ * Returns a CopyFromState, to be passed to NextCopyFrom and related functions.
+ */
+CopyFromState
+BeginCopyFrom(ParseState *pstate,
+			  Relation rel,
+			  Node *whereClause,
+			  const char *filename,
+			  bool is_program,
+			  copy_data_source_cb data_source_cb,
+			  List *attnamelist,
+			  List *options)
+{
+	CopyFromState	cstate;
+	bool		pipe = (filename == NULL);
+	TupleDesc	tupDesc;
+	AttrNumber	num_phys_attrs,
+				num_defaults;
+	FmgrInfo   *in_functions;
+	Oid		   *typioparams;
+	int			attnum;
+	Oid			in_func_oid;
+	int		   *defmap;
+	ExprState **defexprs;
+	MemoryContext oldcontext;
+	bool		volatile_defexprs;
+
+	/* Allocate workspace and zero all fields */
+	cstate = (CopyFromStateData *) palloc0(sizeof(CopyFromStateData));
+
+	/*
+	 * We allocate everything used by a cstate in a new memory context. This
+	 * avoids memory leaks during repeated use of COPY in a query.
+	 */
+	cstate->copycontext = AllocSetContextCreate(CurrentMemoryContext,
+												"COPY",
+												ALLOCSET_DEFAULT_SIZES);
+
+	oldcontext = MemoryContextSwitchTo(cstate->copycontext);
+
+	/* Extract options from the statement node tree */
+	ProcessCopyOptions(pstate, &cstate->opts, true /* is_from */, options);
+
+	/* Process the target relation */
+	cstate->rel = rel;
+
+	tupDesc = RelationGetDescr(cstate->rel);
+
+	/* process commmon options or initialization */
+
+	/* Generate or convert list of attributes to process */
+	cstate->attnumlist = CopyGetAttnums(tupDesc, cstate->rel, attnamelist);
+
+	num_phys_attrs = tupDesc->natts;
+
+	/* Convert FORCE_NOT_NULL name list to per-column flags, check validity */
+	cstate->opts.force_notnull_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+	if (cstate->opts.force_notnull)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.force_notnull);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg("FORCE_NOT_NULL column \"%s\" not referenced by COPY",
+								NameStr(attr->attname))));
+			cstate->opts.force_notnull_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Convert FORCE_NULL name list to per-column flags, check validity */
+	cstate->opts.force_null_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+	if (cstate->opts.force_null)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.force_null);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg("FORCE_NULL column \"%s\" not referenced by COPY",
+								NameStr(attr->attname))));
+			cstate->opts.force_null_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Convert convert_selectively name list to per-column flags */
+	if (cstate->opts.convert_selectively)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		cstate->convert_select_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.convert_select);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg_internal("selected column \"%s\" not referenced by COPY",
+										 NameStr(attr->attname))));
+			cstate->convert_select_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Use client encoding when ENCODING option is not specified. */
+	if (cstate->opts.file_encoding < 0)
+		cstate->file_encoding = pg_get_client_encoding();
+	else
+		cstate->file_encoding = cstate->opts.file_encoding;
+
+	/*
+	 * Set up encoding conversion info.  Even if the file and server encodings
+	 * are the same, we must apply pg_any_to_server() to validate data in
+	 * multibyte encodings.
+	 */
+	cstate->need_transcoding =
+		(cstate->file_encoding != GetDatabaseEncoding() ||
+		 pg_database_encoding_max_length() > 1);
+	/* See Multibyte encoding comment above */
+	cstate->encoding_embeds_ascii = PG_ENCODING_IS_CLIENT_ONLY(cstate->file_encoding);
+
+	cstate->copy_src = COPY_FILE;	/* default */
+
+	cstate->whereClause = whereClause;
+
+	MemoryContextSwitchTo(oldcontext);
+
+	oldcontext = MemoryContextSwitchTo(cstate->copycontext);
+
+	/* Initialize state variables */
+	cstate->reached_eof = false;
+	cstate->eol_type = EOL_UNKNOWN;
+	cstate->cur_relname = RelationGetRelationName(cstate->rel);
+	cstate->cur_lineno = 0;
+	cstate->cur_attname = NULL;
+	cstate->cur_attval = NULL;
+
+	/*
+	 * Set up variables to avoid per-attribute overhead.  attribute_buf and
+	 * raw_buf are used in both text and binary modes, but we use line_buf
+	 * only in text mode.
+	 */
+	initStringInfo(&cstate->attribute_buf);
+	cstate->raw_buf = (char *) palloc(RAW_BUF_SIZE + 1);
+	cstate->raw_buf_index = cstate->raw_buf_len = 0;
+	if (!cstate->opts.binary)
+	{
+		initStringInfo(&cstate->line_buf);
+		cstate->line_buf_converted = false;
+	}
+
+	/* Assign range table, we'll need it in CopyFrom. */
+	if (pstate)
+		cstate->range_table = pstate->p_rtable;
+
+	tupDesc = RelationGetDescr(cstate->rel);
+	num_phys_attrs = tupDesc->natts;
+	num_defaults = 0;
+	volatile_defexprs = false;
+
+	/*
+	 * Pick up the required catalog information for each attribute in the
+	 * relation, including the input function, the element type (to pass to
+	 * the input function), and info about defaults and constraints. (Which
+	 * input function we use depends on text/binary format choice.)
+	 */
+	in_functions = (FmgrInfo *) palloc(num_phys_attrs * sizeof(FmgrInfo));
+	typioparams = (Oid *) palloc(num_phys_attrs * sizeof(Oid));
+	defmap = (int *) palloc(num_phys_attrs * sizeof(int));
+	defexprs = (ExprState **) palloc(num_phys_attrs * sizeof(ExprState *));
+
+	for (attnum = 1; attnum <= num_phys_attrs; attnum++)
+	{
+		Form_pg_attribute att = TupleDescAttr(tupDesc, attnum - 1);
+
+		/* We don't need info for dropped attributes */
+		if (att->attisdropped)
+			continue;
+
+		/* Fetch the input function and typioparam info */
+		if (cstate->opts.binary)
+			getTypeBinaryInputInfo(att->atttypid,
+								   &in_func_oid, &typioparams[attnum - 1]);
+		else
+			getTypeInputInfo(att->atttypid,
+							 &in_func_oid, &typioparams[attnum - 1]);
+		fmgr_info(in_func_oid, &in_functions[attnum - 1]);
+
+		/* Get default info if needed */
+		if (!list_member_int(cstate->attnumlist, attnum) && !att->attgenerated)
+		{
+			/* attribute is NOT to be copied from input */
+			/* use default value if one exists */
+			Expr	   *defexpr = (Expr *) build_column_default(cstate->rel,
+																attnum);
+
+			if (defexpr != NULL)
+			{
+				/* Run the expression through planner */
+				defexpr = expression_planner(defexpr);
+
+				/* Initialize executable expression in copycontext */
+				defexprs[num_defaults] = ExecInitExpr(defexpr, NULL);
+				defmap[num_defaults] = attnum - 1;
+				num_defaults++;
+
+				/*
+				 * If a default expression looks at the table being loaded,
+				 * then it could give the wrong answer when using
+				 * multi-insert. Since database access can be dynamic this is
+				 * hard to test for exactly, so we use the much wider test of
+				 * whether the default expression is volatile. We allow for
+				 * the special case of when the default expression is the
+				 * nextval() of a sequence which in this specific case is
+				 * known to be safe for use with the multi-insert
+				 * optimization. Hence we use this special case function
+				 * checker rather than the standard check for
+				 * contain_volatile_functions().
+				 */
+				if (!volatile_defexprs)
+					volatile_defexprs = contain_volatile_functions_not_nextval((Node *) defexpr);
+			}
+		}
+	}
+
+	/* We keep those variables in cstate. */
+	cstate->in_functions = in_functions;
+	cstate->typioparams = typioparams;
+	cstate->defmap = defmap;
+	cstate->defexprs = defexprs;
+	cstate->volatile_defexprs = volatile_defexprs;
+	cstate->num_defaults = num_defaults;
+	cstate->is_program = is_program;
+
+	if (data_source_cb)
+	{
+		cstate->copy_src = COPY_CALLBACK;
+		cstate->data_source_cb = data_source_cb;
+	}
+	else if (pipe)
+	{
+		Assert(!is_program);	/* the grammar does not allow this */
+		if (whereToSendOutput == DestRemote)
+			ReceiveCopyBegin(cstate);
+		else
+			cstate->copy_file = stdin;
+	}
+	else
+	{
+		cstate->filename = pstrdup(filename);
+
+		if (cstate->is_program)
+		{
+			cstate->copy_file = OpenPipeStream(cstate->filename, PG_BINARY_R);
+			if (cstate->copy_file == NULL)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not execute command \"%s\": %m",
+								cstate->filename)));
+		}
+		else
+		{
+			struct stat st;
+
+			cstate->copy_file = AllocateFile(cstate->filename, PG_BINARY_R);
+			if (cstate->copy_file == NULL)
+			{
+				/* copy errno because ereport subfunctions might change it */
+				int			save_errno = errno;
+
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not open file \"%s\" for reading: %m",
+								cstate->filename),
+						 (save_errno == ENOENT || save_errno == EACCES) ?
+						 errhint("COPY FROM instructs the PostgreSQL server process to read a file. "
+								 "You may want a client-side facility such as psql's \\copy.") : 0));
+			}
+
+			if (fstat(fileno(cstate->copy_file), &st))
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not stat file \"%s\": %m",
+								cstate->filename)));
+
+			if (S_ISDIR(st.st_mode))
+				ereport(ERROR,
+						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+						 errmsg("\"%s\" is a directory", cstate->filename)));
+		}
+	}
+
+	if (cstate->opts.binary)
+	{
+		/* Read and verify binary header */
+		ReceiveCopyBinaryHeader(cstate);
+	}
+
+	/* create workspace for CopyReadAttributes results */
+	if (!cstate->opts.binary)
+	{
+		AttrNumber	attr_count = list_length(cstate->attnumlist);
+
+		cstate->max_fields = attr_count;
+		cstate->raw_fields = (char **) palloc(attr_count * sizeof(char *));
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	return cstate;
+}
+
+/*
+ * Clean up storage and release resources for COPY FROM.
+ */
+void
+EndCopyFrom(CopyFromState cstate)
+{
+	/* No COPY FROM related resources except memory. */
+	if (cstate->is_program)
+	{
+		ClosePipeFromProgram(cstate);
+	}
+	else
+	{
+		if (cstate->filename != NULL && FreeFile(cstate->copy_file))
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not close file \"%s\": %m",
+							cstate->filename)));
+	}
+
+	MemoryContextDelete(cstate->copycontext);
+	pfree(cstate);
+}
+
+/*
+ * Closes the pipe from an external program, checking the pclose() return code.
+ */
+static void
+ClosePipeFromProgram(CopyFromState cstate)
+{
+	int			pclose_rc;
+
+	Assert(cstate->is_program);
+
+	pclose_rc = ClosePipeStream(cstate->copy_file);
+	if (pclose_rc == -1)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not close pipe to external command: %m")));
+	else if (pclose_rc != 0)
+	{
+		/*
+		 * If we ended a COPY FROM PROGRAM before reaching EOF, then it's
+		 * expectable for the called program to fail with SIGPIPE, and we
+		 * should not report that as an error.  Otherwise, SIGPIPE indicates a
+		 * problem.
+		 */
+		if (!cstate->reached_eof &&
+			wait_result_is_signal(pclose_rc, SIGPIPE))
+			return;
+
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("program \"%s\" failed",
+						cstate->filename),
+				 errdetail_internal("%s", wait_result_to_str(pclose_rc))));
+	}
+}

src/backend/commands/copyfromparse.c

+/*-------------------------------------------------------------------------
+ *
+ * copyfromparse.c
+ *		Parse CSV/text/binary format for COPY FROM.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/copyfromparse.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <ctype.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "commands/copy.h"
+#include "commands/copyfrom_internal.h"
+#include "executor/executor.h"
+#include "libpq/libpq.h"
+#include "libpq/pqformat.h"
+#include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "port/pg_bswap.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+
+#define ISOCTAL(c) (((c) >= '0') && ((c) <= '7'))
+#define OCTVALUE(c) ((c) - '0')
+
+/*
+ * These macros centralize code used to process line_buf and raw_buf buffers.
+ * They are macros because they often do continue/break control and to avoid
+ * function call overhead in tight COPY loops.
+ *
+ * We must use "if (1)" because the usual "do {...} while(0)" wrapper would
+ * prevent the continue/break processing from working.  We end the "if (1)"
+ * with "else ((void) 0)" to ensure the "if" does not unintentionally match
+ * any "else" in the calling code, and to avoid any compiler warnings about
+ * empty statements.  See http://www.cit.gu.edu.au/~anthony/info/C/C.macros.
+ */
+
+/*
+ * This keeps the character read at the top of the loop in the buffer
+ * even if there is more than one read-ahead.
+ */
+#define IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(extralen) \
+if (1) \
+{ \
+	if (raw_buf_ptr + (extralen) >= copy_buf_len && !hit_eof) \
+	{ \
+		raw_buf_ptr = prev_raw_ptr; /* undo fetch */ \
+		need_data = true; \
+		continue; \
+	} \
+} else ((void) 0)
+
+/* This consumes the remainder of the buffer and breaks */
+#define IF_NEED_REFILL_AND_EOF_BREAK(extralen) \
+if (1) \
+{ \
+	if (raw_buf_ptr + (extralen) >= copy_buf_len && hit_eof) \
+	{ \
+		if (extralen) \
+			raw_buf_ptr = copy_buf_len; /* consume the partial character */ \
+		/* backslash just before EOF, treat as data char */ \
+		result = true; \
+		break; \
+	} \
+} else ((void) 0)
+
+/*
+ * Transfer any approved data to line_buf; must do this to be sure
+ * there is some room in raw_buf.
+ */
+#define REFILL_LINEBUF \
+if (1) \
+{ \
+	if (raw_buf_ptr > cstate->raw_buf_index) \
+	{ \
+		appendBinaryStringInfo(&cstate->line_buf, \
+							 cstate->raw_buf + cstate->raw_buf_index, \
+							   raw_buf_ptr - cstate->raw_buf_index); \
+		cstate->raw_buf_index = raw_buf_ptr; \
+	} \
+} else ((void) 0)
+
+/* Undo any read-ahead and jump out of the block. */
+#define NO_END_OF_COPY_GOTO \
+if (1) \
+{ \
+	raw_buf_ptr = prev_raw_ptr + 1; \
+	goto not_end_of_copy; \
+} else ((void) 0)
+
+/* NOTE: there's a copy of this in copyto.c */
+static const char BinarySignature[11] = "PGCOPY\n\377\r\n\0";
+
+
+/* non-export function prototypes */
+static bool CopyReadLine(CopyFromState cstate);
+static bool CopyReadLineText(CopyFromState cstate);
+static int	CopyReadAttributesText(CopyFromState cstate);
+static int	CopyReadAttributesCSV(CopyFromState cstate);
+static Datum CopyReadBinaryAttribute(CopyFromState cstate, FmgrInfo *flinfo,
+									 Oid typioparam, int32 typmod,
+									 bool *isnull);
+
+
+/* Low-level communications functions */
+static int	CopyGetData(CopyFromState cstate, void *databuf,
+						int minread, int maxread);
+static bool CopyGetInt32(CopyFromState cstate, int32 *val);
+static bool CopyGetInt16(CopyFromState cstate, int16 *val);
+static bool CopyLoadRawBuf(CopyFromState cstate);
+static int	CopyReadBinaryData(CopyFromState cstate, char *dest, int nbytes);
+
+void
+ReceiveCopyBegin(CopyFromState cstate)
+{
+	if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
+	{
+		/* new way */
+		StringInfoData buf;
+		int			natts = list_length(cstate->attnumlist);
+		int16		format = (cstate->opts.binary ? 1 : 0);
+		int			i;
+
+		pq_beginmessage(&buf, 'G');
+		pq_sendbyte(&buf, format);	/* overall format */
+		pq_sendint16(&buf, natts);
+		for (i = 0; i < natts; i++)
+			pq_sendint16(&buf, format); /* per-column formats */
+		pq_endmessage(&buf);
+		cstate->copy_src = COPY_NEW_FE;
+		cstate->fe_msgbuf = makeStringInfo();
+	}
+	else
+	{
+		/* old way */
+		if (cstate->opts.binary)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("COPY BINARY is not supported to stdout or from stdin")));
+		pq_putemptymessage('G');
+		/* any error in old protocol will make us lose sync */
+		pq_startmsgread();
+		cstate->copy_src = COPY_OLD_FE;
+	}
+	/* We *must* flush here to ensure FE knows it can send. */
+	pq_flush();
+}
+
+void
+ReceiveCopyBinaryHeader(CopyFromState cstate)
+{
+	char		readSig[11];
+	int32		tmp;
+
+	/* Signature */
+	if (CopyReadBinaryData(cstate, readSig, 11) != 11 ||
+		memcmp(readSig, BinarySignature, 11) != 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("COPY file signature not recognized")));
+	/* Flags field */
+	if (!CopyGetInt32(cstate, &tmp))
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("invalid COPY file header (missing flags)")));
+	if ((tmp & (1 << 16)) != 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("invalid COPY file header (WITH OIDS)")));
+	tmp &= ~(1 << 16);
+	if ((tmp >> 16) != 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("unrecognized critical flags in COPY file header")));
+	/* Header extension length */
+	if (!CopyGetInt32(cstate, &tmp) ||
+		tmp < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("invalid COPY file header (missing length)")));
+	/* Skip extension header, if present */
+	while (tmp-- > 0)
+	{
+		if (CopyReadBinaryData(cstate, readSig, 1) != 1)
+			ereport(ERROR,
+					(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+					 errmsg("invalid COPY file header (wrong length)")));
+	}
+}
+
+/*
+ * CopyGetData reads data from the source (file or frontend)
+ *
+ * We attempt to read at least minread, and at most maxread, bytes from
+ * the source.  The actual number of bytes read is returned; if this is
+ * less than minread, EOF was detected.
+ *
+ * Note: when copying from the frontend, we expect a proper EOF mark per
+ * protocol; if the frontend simply drops the connection, we raise error.
+ * It seems unwise to allow the COPY IN to complete normally in that case.
+ *
+ * NB: no data conversion is applied here.
+ */
+static int
+CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
+{
+	int			bytesread = 0;
+
+	switch (cstate->copy_src)
+	{
+		case COPY_FILE:
+			bytesread = fread(databuf, 1, maxread, cstate->copy_file);
+			if (ferror(cstate->copy_file))
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not read from COPY file: %m")));
+			if (bytesread == 0)
+				cstate->reached_eof = true;
+			break;
+		case COPY_OLD_FE:
+
+			/*
+			 * We cannot read more than minread bytes (which in practice is 1)
+			 * because old protocol doesn't have any clear way of separating
+			 * the COPY stream from following data.  This is slow, but not any
+			 * slower than the code path was originally, and we don't care
+			 * much anymore about the performance of old protocol.
+			 */
+			if (pq_getbytes((char *) databuf, minread))
+			{
+				/* Only a \. terminator is legal EOF in old protocol */
+				ereport(ERROR,
+						(errcode(ERRCODE_CONNECTION_FAILURE),
+						 errmsg("unexpected EOF on client connection with an open transaction")));
+			}
+			bytesread = minread;
+			break;
+		case COPY_NEW_FE:
+			while (maxread > 0 && bytesread < minread && !cstate->reached_eof)
+			{
+				int			avail;
+
+				while (cstate->fe_msgbuf->cursor >= cstate->fe_msgbuf->len)
+				{
+					/* Try to receive another message */
+					int			mtype;
+
+			readmessage:
+					HOLD_CANCEL_INTERRUPTS();
+					pq_startmsgread();
+					mtype = pq_getbyte();
+					if (mtype == EOF)
+						ereport(ERROR,
+								(errcode(ERRCODE_CONNECTION_FAILURE),
+								 errmsg("unexpected EOF on client connection with an open transaction")));
+					if (pq_getmessage(cstate->fe_msgbuf, 0))
+						ereport(ERROR,
+								(errcode(ERRCODE_CONNECTION_FAILURE),
+								 errmsg("unexpected EOF on client connection with an open transaction")));
+					RESUME_CANCEL_INTERRUPTS();
+					switch (mtype)
+					{
+						case 'd':	/* CopyData */
+							break;
+						case 'c':	/* CopyDone */
+							/* COPY IN correctly terminated by frontend */
+							cstate->reached_eof = true;
+							return bytesread;
+						case 'f':	/* CopyFail */
+							ereport(ERROR,
+									(errcode(ERRCODE_QUERY_CANCELED),
+									 errmsg("COPY from stdin failed: %s",
+											pq_getmsgstring(cstate->fe_msgbuf))));
+							break;
+						case 'H':	/* Flush */
+						case 'S':	/* Sync */
+
+							/*
+							 * Ignore Flush/Sync for the convenience of client
+							 * libraries (such as libpq) that may send those
+							 * without noticing that the command they just
+							 * sent was COPY.
+							 */
+							goto readmessage;
+						default:
+							ereport(ERROR,
+									(errcode(ERRCODE_PROTOCOL_VIOLATION),
+									 errmsg("unexpected message type 0x%02X during COPY from stdin",
+											mtype)));
+							break;
+					}
+				}
+				avail = cstate->fe_msgbuf->len - cstate->fe_msgbuf->cursor;
+				if (avail > maxread)
+					avail = maxread;
+				pq_copymsgbytes(cstate->fe_msgbuf, databuf, avail);
+				databuf = (void *) ((char *) databuf + avail);
+				maxread -= avail;
+				bytesread += avail;
+			}
+			break;
+		case COPY_CALLBACK:
+			bytesread = cstate->data_source_cb(databuf, minread, maxread);
+			break;
+	}
+
+	return bytesread;
+}
+
+
+/*
+ * These functions do apply some data conversion
+ */
+
+/*
+ * CopyGetInt32 reads an int32 that appears in network byte order
+ *
+ * Returns true if OK, false if EOF
+ */
+static inline bool
+CopyGetInt32(CopyFromState cstate, int32 *val)
+{
+	uint32		buf;
+
+	if (CopyReadBinaryData(cstate, (char *) &buf, sizeof(buf)) != sizeof(buf))
+	{
+		*val = 0;				/* suppress compiler warning */
+		return false;
+	}
+	*val = (int32) pg_ntoh32(buf);
+	return true;
+}
+
+/*
+ * CopyGetInt16 reads an int16 that appears in network byte order
+ */
+static inline bool
+CopyGetInt16(CopyFromState cstate, int16 *val)
+{
+	uint16		buf;
+
+	if (CopyReadBinaryData(cstate, (char *) &buf, sizeof(buf)) != sizeof(buf))
+	{
+		*val = 0;				/* suppress compiler warning */
+		return false;
+	}
+	*val = (int16) pg_ntoh16(buf);
+	return true;
+}
+
+
+/*
+ * CopyLoadRawBuf loads some more data into raw_buf
+ *
+ * Returns true if able to obtain at least one more byte, else false.
+ *
+ * If RAW_BUF_BYTES(cstate) > 0, the unprocessed bytes are moved to the start
+ * of the buffer and then we load more data after that.  This case occurs only
+ * when a multibyte character crosses a bufferload boundary.
+ */
+static bool
+CopyLoadRawBuf(CopyFromState cstate)
+{
+	int			nbytes = RAW_BUF_BYTES(cstate);
+	int			inbytes;
+
+	/* Copy down the unprocessed data if any. */
+	if (nbytes > 0)
+		memmove(cstate->raw_buf, cstate->raw_buf + cstate->raw_buf_index,
+				nbytes);
+
+	inbytes = CopyGetData(cstate, cstate->raw_buf + nbytes,
+						  1, RAW_BUF_SIZE - nbytes);
+	nbytes += inbytes;
+	cstate->raw_buf[nbytes] = '\0';
+	cstate->raw_buf_index = 0;
+	cstate->raw_buf_len = nbytes;
+	return (inbytes > 0);
+}
+
+/*
+ * CopyReadBinaryData
+ *
+ * Reads up to 'nbytes' bytes from cstate->copy_file via cstate->raw_buf
+ * and writes them to 'dest'.  Returns the number of bytes read (which
+ * would be less than 'nbytes' only if we reach EOF).
+ */
+static int
+CopyReadBinaryData(CopyFromState cstate, char *dest, int nbytes)
+{
+	int			copied_bytes = 0;
+
+	if (RAW_BUF_BYTES(cstate) >= nbytes)
+	{
+		/* Enough bytes are present in the buffer. */
+		memcpy(dest, cstate->raw_buf + cstate->raw_buf_index, nbytes);
+		cstate->raw_buf_index += nbytes;
+		copied_bytes = nbytes;
+	}
+	else
+	{
+		/*
+		 * Not enough bytes in the buffer, so must read from the file.  Need
+		 * to loop since 'nbytes' could be larger than the buffer size.
+		 */
+		do
+		{
+			int			copy_bytes;
+
+			/* Load more data if buffer is empty. */
+			if (RAW_BUF_BYTES(cstate) == 0)
+			{
+				if (!CopyLoadRawBuf(cstate))
+					break;		/* EOF */
+			}
+
+			/* Transfer some bytes. */
+			copy_bytes = Min(nbytes - copied_bytes, RAW_BUF_BYTES(cstate));
+			memcpy(dest, cstate->raw_buf + cstate->raw_buf_index, copy_bytes);
+			cstate->raw_buf_index += copy_bytes;
+			dest += copy_bytes;
+			copied_bytes += copy_bytes;
+		} while (copied_bytes < nbytes);
+	}
+
+	return copied_bytes;
+}
+
+/*
+ * Read raw fields in the next line for COPY FROM in text or csv mode.
+ * Return false if no more lines.
+ *
+ * An internal temporary buffer is returned via 'fields'. It is valid until
+ * the next call of the function. Since the function returns all raw fields
+ * in the input file, 'nfields' could be different from the number of columns
+ * in the relation.
+ *
+ * NOTE: force_not_null option are not applied to the returned fields.
+ */
+bool
+NextCopyFromRawFields(CopyFromState cstate, char ***fields, int *nfields)
+{
+	int			fldct;
+	bool		done;
+
+	/* only available for text or csv input */
+	Assert(!cstate->opts.binary);
+
+	/* on input just throw the header line away */
+	if (cstate->cur_lineno == 0 && cstate->opts.header_line)
+	{
+		cstate->cur_lineno++;
+		if (CopyReadLine(cstate))
+			return false;		/* done */
+	}
+
+	cstate->cur_lineno++;
+
+	/* Actually read the line into memory here */
+	done = CopyReadLine(cstate);
+
+	/*
+	 * EOF at start of line means we're done.  If we see EOF after some
+	 * characters, we act as though it was newline followed by EOF, ie,
+	 * process the line and then exit loop on next iteration.
+	 */
+	if (done && cstate->line_buf.len == 0)
+		return false;
+
+	/* Parse the line into de-escaped field values */
+	if (cstate->opts.csv_mode)
+		fldct = CopyReadAttributesCSV(cstate);
+	else
+		fldct = CopyReadAttributesText(cstate);
+
+	*fields = cstate->raw_fields;
+	*nfields = fldct;
+	return true;
+}
+
+/*
+ * Read next tuple from file for COPY FROM. Return false if no more tuples.
+ *
+ * 'econtext' is used to evaluate default expression for each columns not
+ * read from the file. It can be NULL when no default values are used, i.e.
+ * when all columns are read from the file.
+ *
+ * 'values' and 'nulls' arrays must be the same length as columns of the
+ * relation passed to BeginCopyFrom. This function fills the arrays.
+ * Oid of the tuple is returned with 'tupleOid' separately.
+ */
+bool
+NextCopyFrom(CopyFromState cstate, ExprContext *econtext,
+			 Datum *values, bool *nulls)
+{
+	TupleDesc	tupDesc;
+	AttrNumber	num_phys_attrs,
+				attr_count,
+				num_defaults = cstate->num_defaults;
+	FmgrInfo   *in_functions = cstate->in_functions;
+	Oid		   *typioparams = cstate->typioparams;
+	int			i;
+	int		   *defmap = cstate->defmap;
+	ExprState **defexprs = cstate->defexprs;
+
+	tupDesc = RelationGetDescr(cstate->rel);
+	num_phys_attrs = tupDesc->natts;
+	attr_count = list_length(cstate->attnumlist);
+
+	/* Initialize all values for row to NULL */
+	MemSet(values, 0, num_phys_attrs * sizeof(Datum));
+	MemSet(nulls, true, num_phys_attrs * sizeof(bool));
+
+	if (!cstate->opts.binary)
+	{
+		char	  **field_strings;
+		ListCell   *cur;
+		int			fldct;
+		int			fieldno;
+		char	   *string;
+
+		/* read raw fields in the next line */
+		if (!NextCopyFromRawFields(cstate, &field_strings, &fldct))
+			return false;
+
+		/* check for overflowing fields */
+		if (attr_count > 0 && fldct > attr_count)
+			ereport(ERROR,
+					(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+					 errmsg("extra data after last expected column")));
+
+		fieldno = 0;
+
+		/* Loop to read the user attributes on the line. */
+		foreach(cur, cstate->attnumlist)
+		{
+			int			attnum = lfirst_int(cur);
+			int			m = attnum - 1;
+			Form_pg_attribute att = TupleDescAttr(tupDesc, m);
+
+			if (fieldno >= fldct)
+				ereport(ERROR,
+						(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+						 errmsg("missing data for column \"%s\"",
+								NameStr(att->attname))));
+			string = field_strings[fieldno++];
+
+			if (cstate->convert_select_flags &&
+				!cstate->convert_select_flags[m])
+			{
+				/* ignore input field, leaving column as NULL */
+				continue;
+			}
+
+			if (cstate->opts.csv_mode)
+			{
+				if (string == NULL &&
+					cstate->opts.force_notnull_flags[m])
+				{
+					/*
+					 * FORCE_NOT_NULL option is set and column is NULL -
+					 * convert it to the NULL string.
+					 */
+					string = cstate->opts.null_print;
+				}
+				else if (string != NULL && cstate->opts.force_null_flags[m]
+						 && strcmp(string, cstate->opts.null_print) == 0)
+				{
+					/*
+					 * FORCE_NULL option is set and column matches the NULL
+					 * string. It must have been quoted, or otherwise the
+					 * string would already have been set to NULL. Convert it
+					 * to NULL as specified.
+					 */
+					string = NULL;
+				}
+			}
+
+			cstate->cur_attname = NameStr(att->attname);
+			cstate->cur_attval = string;
+			values[m] = InputFunctionCall(&in_functions[m],
+										  string,
+										  typioparams[m],
+										  att->atttypmod);
+			if (string != NULL)
+				nulls[m] = false;
+			cstate->cur_attname = NULL;
+			cstate->cur_attval = NULL;
+		}
+
+		Assert(fieldno == attr_count);
+	}
+	else
+	{
+		/* binary */
+		int16		fld_count;
+		ListCell   *cur;
+
+		cstate->cur_lineno++;
+
+		if (!CopyGetInt16(cstate, &fld_count))
+		{
+			/* EOF detected (end of file, or protocol-level EOF) */
+			return false;
+		}
+
+		if (fld_count == -1)
+		{
+			/*
+			 * Received EOF marker.  In a V3-protocol copy, wait for the
+			 * protocol-level EOF, and complain if it doesn't come
+			 * immediately.  This ensures that we correctly handle CopyFail,
+			 * if client chooses to send that now.
+			 *
+			 * Note that we MUST NOT try to read more data in an old-protocol
+			 * copy, since there is no protocol-level EOF marker then.  We
+			 * could go either way for copy from file, but choose to throw
+			 * error if there's data after the EOF marker, for consistency
+			 * with the new-protocol case.
+			 */
+			char		dummy;
+
+			if (cstate->copy_src != COPY_OLD_FE &&
+				CopyReadBinaryData(cstate, &dummy, 1) > 0)
+				ereport(ERROR,
+						(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+						 errmsg("received copy data after EOF marker")));
+			return false;
+		}
+
+		if (fld_count != attr_count)
+			ereport(ERROR,
+					(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+					 errmsg("row field count is %d, expected %d",
+							(int) fld_count, attr_count)));
+
+		foreach(cur, cstate->attnumlist)
+		{
+			int			attnum = lfirst_int(cur);
+			int			m = attnum - 1;
+			Form_pg_attribute att = TupleDescAttr(tupDesc, m);
+
+			cstate->cur_attname = NameStr(att->attname);
+			values[m] = CopyReadBinaryAttribute(cstate,
+												&in_functions[m],
+												typioparams[m],
+												att->atttypmod,
+												&nulls[m]);
+			cstate->cur_attname = NULL;
+		}
+	}
+
+	/*
+	 * Now compute and insert any defaults available for the columns not
+	 * provided by the input data.  Anything not processed here or above will
+	 * remain NULL.
+	 */
+	for (i = 0; i < num_defaults; i++)
+	{
+		/*
+		 * The caller must supply econtext and have switched into the
+		 * per-tuple memory context in it.
+		 */
+		Assert(econtext != NULL);
+		Assert(CurrentMemoryContext == econtext->ecxt_per_tuple_memory);
+
+		values[defmap[i]] = ExecEvalExpr(defexprs[i], econtext,
+										 &nulls[defmap[i]]);
+	}
+
+	return true;
+}
+
+/*
+ * Read the next input line and stash it in line_buf, with conversion to
+ * server encoding.
+ *
+ * Result is true if read was terminated by EOF, false if terminated
+ * by newline.  The terminating newline or EOF marker is not included
+ * in the final value of line_buf.
+ */
+static bool
+CopyReadLine(CopyFromState cstate)
+{
+	bool		result;
+
+	resetStringInfo(&cstate->line_buf);
+	cstate->line_buf_valid = true;
+
+	/* Mark that encoding conversion hasn't occurred yet */
+	cstate->line_buf_converted = false;
+
+	/* Parse data and transfer into line_buf */
+	result = CopyReadLineText(cstate);
+
+	if (result)
+	{
+		/*
+		 * Reached EOF.  In protocol version 3, we should ignore anything
+		 * after \. up to the protocol end of copy data.  (XXX maybe better
+		 * not to treat \. as special?)
+		 */
+		if (cstate->copy_src == COPY_NEW_FE)
+		{
+			do
+			{
+				cstate->raw_buf_index = cstate->raw_buf_len;
+			} while (CopyLoadRawBuf(cstate));
+		}
+	}
+	else
+	{
+		/*
+		 * If we didn't hit EOF, then we must have transferred the EOL marker
+		 * to line_buf along with the data.  Get rid of it.
+		 */
+		switch (cstate->eol_type)
+		{
+			case EOL_NL:
+				Assert(cstate->line_buf.len >= 1);
+				Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\n');
+				cstate->line_buf.len--;
+				cstate->line_buf.data[cstate->line_buf.len] = '\0';
+				break;
+			case EOL_CR:
+				Assert(cstate->line_buf.len >= 1);
+				Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\r');
+				cstate->line_buf.len--;
+				cstate->line_buf.data[cstate->line_buf.len] = '\0';
+				break;
+			case EOL_CRNL:
+				Assert(cstate->line_buf.len >= 2);
+				Assert(cstate->line_buf.data[cstate->line_buf.len - 2] == '\r');
+				Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\n');
+				cstate->line_buf.len -= 2;
+				cstate->line_buf.data[cstate->line_buf.len] = '\0';
+				break;
+			case EOL_UNKNOWN:
+				/* shouldn't get here */
+				Assert(false);
+				break;
+		}
+	}
+
+	/* Done reading the line.  Convert it to server encoding. */
+	if (cstate->need_transcoding)
+	{
+		char	   *cvt;
+
+		cvt = pg_any_to_server(cstate->line_buf.data,
+							   cstate->line_buf.len,
+							   cstate->file_encoding);
+		if (cvt != cstate->line_buf.data)
+		{
+			/* transfer converted data back to line_buf */
+			resetStringInfo(&cstate->line_buf);
+			appendBinaryStringInfo(&cstate->line_buf, cvt, strlen(cvt));
+			pfree(cvt);
+		}
+	}
+
+	/* Now it's safe to use the buffer in error messages */
+	cstate->line_buf_converted = true;
+
+	return result;
+}
+
+/*
+ * CopyReadLineText - inner loop of CopyReadLine for text mode
+ */
+static bool
+CopyReadLineText(CopyFromState cstate)
+{
+	char	   *copy_raw_buf;
+	int			raw_buf_ptr;
+	int			copy_buf_len;
+	bool		need_data = false;
+	bool		hit_eof = false;
+	bool		result = false;
+	char		mblen_str[2];
+
+	/* CSV variables */
+	bool		first_char_in_line = true;
+	bool		in_quote = false,
+				last_was_esc = false;
+	char		quotec = '\0';
+	char		escapec = '\0';
+
+	if (cstate->opts.csv_mode)
+	{
+		quotec = cstate->opts.quote[0];
+		escapec = cstate->opts.escape[0];
+		/* ignore special escape processing if it's the same as quotec */
+		if (quotec == escapec)
+			escapec = '\0';
+	}
+
+	mblen_str[1] = '\0';
+
+	/*
+	 * The objective of this loop is to transfer the entire next input line
+	 * into line_buf.  Hence, we only care for detecting newlines (\r and/or
+	 * \n) and the end-of-copy marker (\.).
+	 *
+	 * In CSV mode, \r and \n inside a quoted field are just part of the data
+	 * value and are put in line_buf.  We keep just enough state to know if we
+	 * are currently in a quoted field or not.
+	 *
+	 * These four characters, and the CSV escape and quote characters, are
+	 * assumed the same in frontend and backend encodings.
+	 *
+	 * For speed, we try to move data from raw_buf to line_buf in chunks
+	 * rather than one character at a time.  raw_buf_ptr points to the next
+	 * character to examine; any characters from raw_buf_index to raw_buf_ptr
+	 * have been determined to be part of the line, but not yet transferred to
+	 * line_buf.
+	 *
+	 * For a little extra speed within the loop, we copy raw_buf and
+	 * raw_buf_len into local variables.
+	 */
+	copy_raw_buf = cstate->raw_buf;
+	raw_buf_ptr = cstate->raw_buf_index;
+	copy_buf_len = cstate->raw_buf_len;
+
+	for (;;)
+	{
+		int			prev_raw_ptr;
+		char		c;
+
+		/*
+		 * Load more data if needed.  Ideally we would just force four bytes
+		 * of read-ahead and avoid the many calls to
+		 * IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(), but the COPY_OLD_FE protocol
+		 * does not allow us to read too far ahead or we might read into the
+		 * next data, so we read-ahead only as far we know we can.  One
+		 * optimization would be to read-ahead four byte here if
+		 * cstate->copy_src != COPY_OLD_FE, but it hardly seems worth it,
+		 * considering the size of the buffer.
+		 */
+		if (raw_buf_ptr >= copy_buf_len || need_data)
+		{
+			REFILL_LINEBUF;
+
+			/*
+			 * Try to read some more data.  This will certainly reset
+			 * raw_buf_index to zero, and raw_buf_ptr must go with it.
+			 */
+			if (!CopyLoadRawBuf(cstate))
+				hit_eof = true;
+			raw_buf_ptr = 0;
+			copy_buf_len = cstate->raw_buf_len;
+
+			/*
+			 * If we are completely out of data, break out of the loop,
+			 * reporting EOF.
+			 */
+			if (copy_buf_len <= 0)
+			{
+				result = true;
+				break;
+			}
+			need_data = false;
+		}
+
+		/* OK to fetch a character */
+		prev_raw_ptr = raw_buf_ptr;
+		c = copy_raw_buf[raw_buf_ptr++];
+
+		if (cstate->opts.csv_mode)
+		{
+			/*
+			 * If character is '\\' or '\r', we may need to look ahead below.
+			 * Force fetch of the next character if we don't already have it.
+			 * We need to do this before changing CSV state, in case one of
+			 * these characters is also the quote or escape character.
+			 *
+			 * Note: old-protocol does not like forced prefetch, but it's OK
+			 * here since we cannot validly be at EOF.
+			 */
+			if (c == '\\' || c == '\r')
+			{
+				IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
+			}
+
+			/*
+			 * Dealing with quotes and escapes here is mildly tricky. If the
+			 * quote char is also the escape char, there's no problem - we
+			 * just use the char as a toggle. If they are different, we need
+			 * to ensure that we only take account of an escape inside a
+			 * quoted field and immediately preceding a quote char, and not
+			 * the second in an escape-escape sequence.
+			 */
+			if (in_quote && c == escapec)
+				last_was_esc = !last_was_esc;
+			if (c == quotec && !last_was_esc)
+				in_quote = !in_quote;
+			if (c != escapec)
+				last_was_esc = false;
+
+			/*
+			 * Updating the line count for embedded CR and/or LF chars is
+			 * necessarily a little fragile - this test is probably about the
+			 * best we can do.  (XXX it's arguable whether we should do this
+			 * at all --- is cur_lineno a physical or logical count?)
+			 */
+			if (in_quote && c == (cstate->eol_type == EOL_NL ? '\n' : '\r'))
+				cstate->cur_lineno++;
+		}
+
+		/* Process \r */
+		if (c == '\r' && (!cstate->opts.csv_mode || !in_quote))
+		{
+			/* Check for \r\n on first line, _and_ handle \r\n. */
+			if (cstate->eol_type == EOL_UNKNOWN ||
+				cstate->eol_type == EOL_CRNL)
+			{
+				/*
+				 * If need more data, go back to loop top to load it.
+				 *
+				 * Note that if we are at EOF, c will wind up as '\0' because
+				 * of the guaranteed pad of raw_buf.
+				 */
+				IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
+
+				/* get next char */
+				c = copy_raw_buf[raw_buf_ptr];
+
+				if (c == '\n')
+				{
+					raw_buf_ptr++;	/* eat newline */
+					cstate->eol_type = EOL_CRNL;	/* in case not set yet */
+				}
+				else
+				{
+					/* found \r, but no \n */
+					if (cstate->eol_type == EOL_CRNL)
+						ereport(ERROR,
+								(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+								 !cstate->opts.csv_mode ?
+								 errmsg("literal carriage return found in data") :
+								 errmsg("unquoted carriage return found in data"),
+								 !cstate->opts.csv_mode ?
+								 errhint("Use \"\\r\" to represent carriage return.") :
+								 errhint("Use quoted CSV field to represent carriage return.")));
+
+					/*
+					 * if we got here, it is the first line and we didn't find
+					 * \n, so don't consume the peeked character
+					 */
+					cstate->eol_type = EOL_CR;
+				}
+			}
+			else if (cstate->eol_type == EOL_NL)
+				ereport(ERROR,
+						(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+						 !cstate->opts.csv_mode ?
+						 errmsg("literal carriage return found in data") :
+						 errmsg("unquoted carriage return found in data"),
+						 !cstate->opts.csv_mode ?
+						 errhint("Use \"\\r\" to represent carriage return.") :
+						 errhint("Use quoted CSV field to represent carriage return.")));
+			/* If reach here, we have found the line terminator */
+			break;
+		}
+
+		/* Process \n */
+		if (c == '\n' && (!cstate->opts.csv_mode || !in_quote))
+		{
+			if (cstate->eol_type == EOL_CR || cstate->eol_type == EOL_CRNL)
+				ereport(ERROR,
+						(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+						 !cstate->opts.csv_mode ?
+						 errmsg("literal newline found in data") :
+						 errmsg("unquoted newline found in data"),
+						 !cstate->opts.csv_mode ?
+						 errhint("Use \"\\n\" to represent newline.") :
+						 errhint("Use quoted CSV field to represent newline.")));
+			cstate->eol_type = EOL_NL;	/* in case not set yet */
+			/* If reach here, we have found the line terminator */
+			break;
+		}
+
+		/*
+		 * In CSV mode, we only recognize \. alone on a line.  This is because
+		 * \. is a valid CSV data value.
+		 */
+		if (c == '\\' && (!cstate->opts.csv_mode || first_char_in_line))
+		{
+			char		c2;
+
+			IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
+			IF_NEED_REFILL_AND_EOF_BREAK(0);
+
+			/* -----
+			 * get next character
+			 * Note: we do not change c so if it isn't \., we can fall
+			 * through and continue processing for file encoding.
+			 * -----
+			 */
+			c2 = copy_raw_buf[raw_buf_ptr];
+
+			if (c2 == '.')
+			{
+				raw_buf_ptr++;	/* consume the '.' */
+
+				/*
+				 * Note: if we loop back for more data here, it does not
+				 * matter that the CSV state change checks are re-executed; we
+				 * will come back here with no important state changed.
+				 */
+				if (cstate->eol_type == EOL_CRNL)
+				{
+					/* Get the next character */
+					IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
+					/* if hit_eof, c2 will become '\0' */
+					c2 = copy_raw_buf[raw_buf_ptr++];
+
+					if (c2 == '\n')
+					{
+						if (!cstate->opts.csv_mode)
+							ereport(ERROR,
+									(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+									 errmsg("end-of-copy marker does not match previous newline style")));
+						else
+							NO_END_OF_COPY_GOTO;
+					}
+					else if (c2 != '\r')
+					{
+						if (!cstate->opts.csv_mode)
+							ereport(ERROR,
+									(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+									 errmsg("end-of-copy marker corrupt")));
+						else
+							NO_END_OF_COPY_GOTO;
+					}
+				}
+
+				/* Get the next character */
+				IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
+				/* if hit_eof, c2 will become '\0' */
+				c2 = copy_raw_buf[raw_buf_ptr++];
+
+				if (c2 != '\r' && c2 != '\n')
+				{
+					if (!cstate->opts.csv_mode)
+						ereport(ERROR,
+								(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+								 errmsg("end-of-copy marker corrupt")));
+					else
+						NO_END_OF_COPY_GOTO;
+				}
+
+				if ((cstate->eol_type == EOL_NL && c2 != '\n') ||
+					(cstate->eol_type == EOL_CRNL && c2 != '\n') ||
+					(cstate->eol_type == EOL_CR && c2 != '\r'))
+				{
+					ereport(ERROR,
+							(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+							 errmsg("end-of-copy marker does not match previous newline style")));
+				}
+
+				/*
+				 * Transfer only the data before the \. into line_buf, then
+				 * discard the data and the \. sequence.
+				 */
+				if (prev_raw_ptr > cstate->raw_buf_index)
+					appendBinaryStringInfo(&cstate->line_buf,
+										   cstate->raw_buf + cstate->raw_buf_index,
+										   prev_raw_ptr - cstate->raw_buf_index);
+				cstate->raw_buf_index = raw_buf_ptr;
+				result = true;	/* report EOF */
+				break;
+			}
+			else if (!cstate->opts.csv_mode)
+
+				/*
+				 * If we are here, it means we found a backslash followed by
+				 * something other than a period.  In non-CSV mode, anything
+				 * after a backslash is special, so we skip over that second
+				 * character too.  If we didn't do that \\. would be
+				 * considered an eof-of copy, while in non-CSV mode it is a
+				 * literal backslash followed by a period.  In CSV mode,
+				 * backslashes are not special, so we want to process the
+				 * character after the backslash just like a normal character,
+				 * so we don't increment in those cases.
+				 */
+				raw_buf_ptr++;
+		}
+
+		/*
+		 * This label is for CSV cases where \. appears at the start of a
+		 * line, but there is more text after it, meaning it was a data value.
+		 * We are more strict for \. in CSV mode because \. could be a data
+		 * value, while in non-CSV mode, \. cannot be a data value.
+		 */
+not_end_of_copy:
+
+		/*
+		 * Process all bytes of a multi-byte character as a group.
+		 *
+		 * We only support multi-byte sequences where the first byte has the
+		 * high-bit set, so as an optimization we can avoid this block
+		 * entirely if it is not set.
+		 */
+		if (cstate->encoding_embeds_ascii && IS_HIGHBIT_SET(c))
+		{
+			int			mblen;
+
+			/*
+			 * It is enough to look at the first byte in all our encodings, to
+			 * get the length.  (GB18030 is a bit special, but still works for
+			 * our purposes; see comment in pg_gb18030_mblen())
+			 */
+			mblen_str[0] = c;
+			mblen = pg_encoding_mblen(cstate->file_encoding, mblen_str);
+
+			IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(mblen - 1);
+			IF_NEED_REFILL_AND_EOF_BREAK(mblen - 1);
+			raw_buf_ptr += mblen - 1;
+		}
+		first_char_in_line = false;
+	}							/* end of outer loop */
+
+	/*
+	 * Transfer any still-uncopied data to line_buf.
+	 */
+	REFILL_LINEBUF;
+
+	return result;
+}
+
+/*
+ *	Return decimal value for a hexadecimal digit
+ */
+static int
+GetDecimalFromHex(char hex)
+{
+	if (isdigit((unsigned char) hex))
+		return hex - '0';
+	else
+		return tolower((unsigned char) hex) - 'a' + 10;
+}
+
+/*
+ * Parse the current line into separate attributes (fields),
+ * performing de-escaping as needed.
+ *
+ * The input is in line_buf.  We use attribute_buf to hold the result
+ * strings.  cstate->raw_fields[k] is set to point to the k'th attribute
+ * string, or NULL when the input matches the null marker string.
+ * This array is expanded as necessary.
+ *
+ * (Note that the caller cannot check for nulls since the returned
+ * string would be the post-de-escaping equivalent, which may look
+ * the same as some valid data string.)
+ *
+ * delim is the column delimiter string (must be just one byte for now).
+ * null_print is the null marker string.  Note that this is compared to
+ * the pre-de-escaped input string.
+ *
+ * The return value is the number of fields actually read.
+ */
+static int
+CopyReadAttributesText(CopyFromState cstate)
+{
+	char		delimc = cstate->opts.delim[0];
+	int			fieldno;
+	char	   *output_ptr;
+	char	   *cur_ptr;
+	char	   *line_end_ptr;
+
+	/*
+	 * We need a special case for zero-column tables: check that the input
+	 * line is empty, and return.
+	 */
+	if (cstate->max_fields <= 0)
+	{
+		if (cstate->line_buf.len != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+					 errmsg("extra data after last expected column")));
+		return 0;
+	}
+
+	resetStringInfo(&cstate->attribute_buf);
+
+	/*
+	 * The de-escaped attributes will certainly not be longer than the input
+	 * data line, so we can just force attribute_buf to be large enough and
+	 * then transfer data without any checks for enough space.  We need to do
+	 * it this way because enlarging attribute_buf mid-stream would invalidate
+	 * pointers already stored into cstate->raw_fields[].
+	 */
+	if (cstate->attribute_buf.maxlen <= cstate->line_buf.len)
+		enlargeStringInfo(&cstate->attribute_buf, cstate->line_buf.len);
+	output_ptr = cstate->attribute_buf.data;
+
+	/* set pointer variables for loop */
+	cur_ptr = cstate->line_buf.data;
+	line_end_ptr = cstate->line_buf.data + cstate->line_buf.len;
+
+	/* Outer loop iterates over fields */
+	fieldno = 0;
+	for (;;)
+	{
+		bool		found_delim = false;
+		char	   *start_ptr;
+		char	   *end_ptr;
+		int			input_len;
+		bool		saw_non_ascii = false;
+
+		/* Make sure there is enough space for the next value */
+		if (fieldno >= cstate->max_fields)
+		{
+			cstate->max_fields *= 2;
+			cstate->raw_fields =
+				repalloc(cstate->raw_fields, cstate->max_fields * sizeof(char *));
+		}
+
+		/* Remember start of field on both input and output sides */
+		start_ptr = cur_ptr;
+		cstate->raw_fields[fieldno] = output_ptr;
+
+		/*
+		 * Scan data for field.
+		 *
+		 * Note that in this loop, we are scanning to locate the end of field
+		 * and also speculatively performing de-escaping.  Once we find the
+		 * end-of-field, we can match the raw field contents against the null
+		 * marker string.  Only after that comparison fails do we know that
+		 * de-escaping is actually the right thing to do; therefore we *must
+		 * not* throw any syntax errors before we've done the null-marker
+		 * check.
+		 */
+		for (;;)
+		{
+			char		c;
+
+			end_ptr = cur_ptr;
+			if (cur_ptr >= line_end_ptr)
+				break;
+			c = *cur_ptr++;
+			if (c == delimc)
+			{
+				found_delim = true;
+				break;
+			}
+			if (c == '\\')
+			{
+				if (cur_ptr >= line_end_ptr)
+					break;
+				c = *cur_ptr++;
+				switch (c)
+				{
+					case '0':
+					case '1':
+					case '2':
+					case '3':
+					case '4':
+					case '5':
+					case '6':
+					case '7':
+						{
+							/* handle \013 */
+							int			val;
+
+							val = OCTVALUE(c);
+							if (cur_ptr < line_end_ptr)
+							{
+								c = *cur_ptr;
+								if (ISOCTAL(c))
+								{
+									cur_ptr++;
+									val = (val << 3) + OCTVALUE(c);
+									if (cur_ptr < line_end_ptr)
+									{
+										c = *cur_ptr;
+										if (ISOCTAL(c))
+										{
+											cur_ptr++;
+											val = (val << 3) + OCTVALUE(c);
+										}
+									}
+								}
+							}
+							c = val & 0377;
+							if (c == '\0' || IS_HIGHBIT_SET(c))
+								saw_non_ascii = true;
+						}
+						break;
+					case 'x':
+						/* Handle \x3F */
+						if (cur_ptr < line_end_ptr)
+						{
+							char		hexchar = *cur_ptr;
+
+							if (isxdigit((unsigned char) hexchar))
+							{
+								int			val = GetDecimalFromHex(hexchar);
+
+								cur_ptr++;
+								if (cur_ptr < line_end_ptr)
+								{
+									hexchar = *cur_ptr;
+									if (isxdigit((unsigned char) hexchar))
+									{
+										cur_ptr++;
+										val = (val << 4) + GetDecimalFromHex(hexchar);
+									}
+								}
+								c = val & 0xff;
+								if (c == '\0' || IS_HIGHBIT_SET(c))
+									saw_non_ascii = true;
+							}
+						}
+						break;
+					case 'b':
+						c = '\b';
+						break;
+					case 'f':
+						c = '\f';
+						break;
+					case 'n':
+						c = '\n';
+						break;
+					case 'r':
+						c = '\r';
+						break;
+					case 't':
+						c = '\t';
+						break;
+					case 'v':
+						c = '\v';
+						break;
+
+						/*
+						 * in all other cases, take the char after '\'
+						 * literally
+						 */
+				}
+			}
+
+			/* Add c to output string */
+			*output_ptr++ = c;
+		}
+
+		/* Check whether raw input matched null marker */
+		input_len = end_ptr - start_ptr;
+		if (input_len == cstate->opts.null_print_len &&
+			strncmp(start_ptr, cstate->opts.null_print, input_len) == 0)
+			cstate->raw_fields[fieldno] = NULL;
+		else
+		{
+			/*
+			 * At this point we know the field is supposed to contain data.
+			 *
+			 * If we de-escaped any non-7-bit-ASCII chars, make sure the
+			 * resulting string is valid data for the db encoding.
+			 */
+			if (saw_non_ascii)
+			{
+				char	   *fld = cstate->raw_fields[fieldno];
+
+				pg_verifymbstr(fld, output_ptr - fld, false);
+			}
+		}
+
+		/* Terminate attribute value in output area */
+		*output_ptr++ = '\0';
+
+		fieldno++;
+		/* Done if we hit EOL instead of a delim */
+		if (!found_delim)
+			break;
+	}
+
+	/* Clean up state of attribute_buf */
+	output_ptr--;
+	Assert(*output_ptr == '\0');
+	cstate->attribute_buf.len = (output_ptr - cstate->attribute_buf.data);
+
+	return fieldno;
+}
+
+/*
+ * Parse the current line into separate attributes (fields),
+ * performing de-escaping as needed.  This has exactly the same API as
+ * CopyReadAttributesText, except we parse the fields according to
+ * "standard" (i.e. common) CSV usage.
+ */
+static int
+CopyReadAttributesCSV(CopyFromState cstate)
+{
+	char		delimc = cstate->opts.delim[0];
+	char		quotec = cstate->opts.quote[0];
+	char		escapec = cstate->opts.escape[0];
+	int			fieldno;
+	char	   *output_ptr;
+	char	   *cur_ptr;
+	char	   *line_end_ptr;
+
+	/*
+	 * We need a special case for zero-column tables: check that the input
+	 * line is empty, and return.
+	 */
+	if (cstate->max_fields <= 0)
+	{
+		if (cstate->line_buf.len != 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+					 errmsg("extra data after last expected column")));
+		return 0;
+	}
+
+	resetStringInfo(&cstate->attribute_buf);
+
+	/*
+	 * The de-escaped attributes will certainly not be longer than the input
+	 * data line, so we can just force attribute_buf to be large enough and
+	 * then transfer data without any checks for enough space.  We need to do
+	 * it this way because enlarging attribute_buf mid-stream would invalidate
+	 * pointers already stored into cstate->raw_fields[].
+	 */
+	if (cstate->attribute_buf.maxlen <= cstate->line_buf.len)
+		enlargeStringInfo(&cstate->attribute_buf, cstate->line_buf.len);
+	output_ptr = cstate->attribute_buf.data;
+
+	/* set pointer variables for loop */
+	cur_ptr = cstate->line_buf.data;
+	line_end_ptr = cstate->line_buf.data + cstate->line_buf.len;
+
+	/* Outer loop iterates over fields */
+	fieldno = 0;
+	for (;;)
+	{
+		bool		found_delim = false;
+		bool		saw_quote = false;
+		char	   *start_ptr;
+		char	   *end_ptr;
+		int			input_len;
+
+		/* Make sure there is enough space for the next value */
+		if (fieldno >= cstate->max_fields)
+		{
+			cstate->max_fields *= 2;
+			cstate->raw_fields =
+				repalloc(cstate->raw_fields, cstate->max_fields * sizeof(char *));
+		}
+
+		/* Remember start of field on both input and output sides */
+		start_ptr = cur_ptr;
+		cstate->raw_fields[fieldno] = output_ptr;
+
+		/*
+		 * Scan data for field,
+		 *
+		 * The loop starts in "not quote" mode and then toggles between that
+		 * and "in quote" mode. The loop exits normally if it is in "not
+		 * quote" mode and a delimiter or line end is seen.
+		 */
+		for (;;)
+		{
+			char		c;
+
+			/* Not in quote */
+			for (;;)
+			{
+				end_ptr = cur_ptr;
+				if (cur_ptr >= line_end_ptr)
+					goto endfield;
+				c = *cur_ptr++;
+				/* unquoted field delimiter */
+				if (c == delimc)
+				{
+					found_delim = true;
+					goto endfield;
+				}
+				/* start of quoted field (or part of field) */
+				if (c == quotec)
+				{
+					saw_quote = true;
+					break;
+				}
+				/* Add c to output string */
+				*output_ptr++ = c;
+			}
+
+			/* In quote */
+			for (;;)
+			{
+				end_ptr = cur_ptr;
+				if (cur_ptr >= line_end_ptr)
+					ereport(ERROR,
+							(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+							 errmsg("unterminated CSV quoted field")));
+
+				c = *cur_ptr++;
+
+				/* escape within a quoted field */
+				if (c == escapec)
+				{
+					/*
+					 * peek at the next char if available, and escape it if it
+					 * is an escape char or a quote char
+					 */
+					if (cur_ptr < line_end_ptr)
+					{
+						char		nextc = *cur_ptr;
+
+						if (nextc == escapec || nextc == quotec)
+						{
+							*output_ptr++ = nextc;
+							cur_ptr++;
+							continue;
+						}
+					}
+				}
+
+				/*
+				 * end of quoted field. Must do this test after testing for
+				 * escape in case quote char and escape char are the same
+				 * (which is the common case).
+				 */
+				if (c == quotec)
+					break;
+
+				/* Add c to output string */
+				*output_ptr++ = c;
+			}
+		}
+endfield:
+
+		/* Terminate attribute value in output area */
+		*output_ptr++ = '\0';
+
+		/* Check whether raw input matched null marker */
+		input_len = end_ptr - start_ptr;
+		if (!saw_quote && input_len == cstate->opts.null_print_len &&
+			strncmp(start_ptr, cstate->opts.null_print, input_len) == 0)
+			cstate->raw_fields[fieldno] = NULL;
+
+		fieldno++;
+		/* Done if we hit EOL instead of a delim */
+		if (!found_delim)
+			break;
+	}
+
+	/* Clean up state of attribute_buf */
+	output_ptr--;
+	Assert(*output_ptr == '\0');
+	cstate->attribute_buf.len = (output_ptr - cstate->attribute_buf.data);
+
+	return fieldno;
+}
+
+
+/*
+ * Read a binary attribute
+ */
+static Datum
+CopyReadBinaryAttribute(CopyFromState cstate, FmgrInfo *flinfo,
+						Oid typioparam, int32 typmod,
+						bool *isnull)
+{
+	int32		fld_size;
+	Datum		result;
+
+	if (!CopyGetInt32(cstate, &fld_size))
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("unexpected EOF in COPY data")));
+	if (fld_size == -1)
+	{
+		*isnull = true;
+		return ReceiveFunctionCall(flinfo, NULL, typioparam, typmod);
+	}
+	if (fld_size < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("invalid field size")));
+
+	/* reset attribute_buf to empty, and load raw data in it */
+	resetStringInfo(&cstate->attribute_buf);
+
+	enlargeStringInfo(&cstate->attribute_buf, fld_size);
+	if (CopyReadBinaryData(cstate, cstate->attribute_buf.data,
+						   fld_size) != fld_size)
+		ereport(ERROR,
+				(errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
+				 errmsg("unexpected EOF in COPY data")));
+
+	cstate->attribute_buf.len = fld_size;
+	cstate->attribute_buf.data[fld_size] = '\0';
+
+	/* Call the column type's binary input converter */
+	result = ReceiveFunctionCall(flinfo, &cstate->attribute_buf,
+								 typioparam, typmod);
+
+	/* Trouble if it didn't eat the whole buffer */
+	if (cstate->attribute_buf.cursor != cstate->attribute_buf.len)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
+				 errmsg("incorrect binary data format")));
+
+	*isnull = false;
+	return result;
+}

src/backend/commands/copyto.c

+/*-------------------------------------------------------------------------
+ *
+ * copyto.c
+ *		COPY <table> TO file/program/client
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/copyto.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <ctype.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "access/heapam.h"
+#include "access/htup_details.h"
+#include "access/tableam.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "commands/copy.h"
+#include "executor/execdesc.h"
+#include "executor/executor.h"
+#include "executor/tuptable.h"
+#include "libpq/libpq.h"
+#include "libpq/pqformat.h"
+#include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "optimizer/optimizer.h"
+#include "rewrite/rewriteHandler.h"
+#include "storage/fd.h"
+#include "tcop/tcopprot.h"
+#include "utils/lsyscache.h"
+#include "utils/memutils.h"
+#include "utils/partcache.h"
+#include "utils/rel.h"
+#include "utils/snapmgr.h"
+
+/*
+ * Represents the different dest cases we need to worry about at
+ * the bottom level
+ */
+typedef enum CopyDest
+{
+	COPY_FILE,					/* to file (or a piped program) */
+	COPY_OLD_FE,				/* to frontend (2.0 protocol) */
+	COPY_NEW_FE,				/* to frontend (3.0 protocol) */
+} CopyDest;
+
+/*
+ * This struct contains all the state variables used throughout a COPY TO
+ * operation.
+ *
+ * Multi-byte encodings: all supported client-side encodings encode multi-byte
+ * characters by having the first byte's high bit set. Subsequent bytes of the
+ * character can have the high bit not set. When scanning data in such an
+ * encoding to look for a match to a single-byte (ie ASCII) character, we must
+ * use the full pg_encoding_mblen() machinery to skip over multibyte
+ * characters, else we might find a false match to a trailing byte. In
+ * supported server encodings, there is no possibility of a false match, and
+ * it's faster to make useless comparisons to trailing bytes than it is to
+ * invoke pg_encoding_mblen() to skip over them. encoding_embeds_ascii is true
+ * when we have to do it the hard way.
+ */
+typedef struct CopyToStateData
+{
+	/* low-level state data */
+	CopyDest	copy_dest;		/* type of copy source/destination */
+	FILE	   *copy_file;		/* used if copy_dest == COPY_FILE */
+	StringInfo	fe_msgbuf;		/* used for all dests during COPY TO */
+
+	int			file_encoding;	/* file or remote side's character encoding */
+	bool		need_transcoding;	/* file encoding diff from server? */
+	bool		encoding_embeds_ascii;	/* ASCII can be non-first byte? */
+
+	/* parameters from the COPY command */
+	Relation	rel;			/* relation to copy to */
+	QueryDesc  *queryDesc;		/* executable query to copy from */
+	List	   *attnumlist;		/* integer list of attnums to copy */
+	char	   *filename;		/* filename, or NULL for STDOUT */
+	bool		is_program;		/* is 'filename' a program to popen? */
+
+	CopyFormatOptions opts;
+	Node	   *whereClause;	/* WHERE condition (or NULL) */
+
+	/*
+	 * Working state
+	 */
+	MemoryContext copycontext;	/* per-copy execution context */
+
+	FmgrInfo   *out_functions;	/* lookup info for output functions */
+	MemoryContext rowcontext;	/* per-row evaluation context */
+
+} CopyToStateData;
+
+/* DestReceiver for COPY (query) TO */
+typedef struct
+{
+	DestReceiver pub;			/* publicly-known function pointers */
+	CopyToState	cstate;			/* CopyToStateData for the command */
+	uint64		processed;		/* # of tuples processed */
+} DR_copy;
+
+/* NOTE: there's a copy of this in copyfromparse.c */
+static const char BinarySignature[11] = "PGCOPY\n\377\r\n\0";
+
+
+/* non-export function prototypes */
+static void EndCopy(CopyToState cstate);
+static void ClosePipeToProgram(CopyToState cstate);
+static uint64 CopyTo(CopyToState cstate);
+static void CopyOneRowTo(CopyToState cstate, TupleTableSlot *slot);
+static void CopyAttributeOutText(CopyToState cstate, char *string);
+static void CopyAttributeOutCSV(CopyToState cstate, char *string,
+								bool use_quote, bool single_attr);
+
+/* Low-level communications functions */
+static void SendCopyBegin(CopyToState cstate);
+static void SendCopyEnd(CopyToState cstate);
+static void CopySendData(CopyToState cstate, const void *databuf, int datasize);
+static void CopySendString(CopyToState cstate, const char *str);
+static void CopySendChar(CopyToState cstate, char c);
+static void CopySendEndOfRow(CopyToState cstate);
+static void CopySendInt32(CopyToState cstate, int32 val);
+static void CopySendInt16(CopyToState cstate, int16 val);
+
+
+/*
+ * Send copy start/stop messages for frontend copies.  These have changed
+ * in past protocol redesigns.
+ */
+static void
+SendCopyBegin(CopyToState cstate)
+{
+	if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
+	{
+		/* new way */
+		StringInfoData buf;
+		int			natts = list_length(cstate->attnumlist);
+		int16		format = (cstate->opts.binary ? 1 : 0);
+		int			i;
+
+		pq_beginmessage(&buf, 'H');
+		pq_sendbyte(&buf, format);	/* overall format */
+		pq_sendint16(&buf, natts);
+		for (i = 0; i < natts; i++)
+			pq_sendint16(&buf, format); /* per-column formats */
+		pq_endmessage(&buf);
+		cstate->copy_dest = COPY_NEW_FE;
+	}
+	else
+	{
+		/* old way */
+		if (cstate->opts.binary)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("COPY BINARY is not supported to stdout or from stdin")));
+		pq_putemptymessage('H');
+		/* grottiness needed for old COPY OUT protocol */
+		pq_startcopyout();
+		cstate->copy_dest = COPY_OLD_FE;
+	}
+}
+
+static void
+SendCopyEnd(CopyToState cstate)
+{
+	if (cstate->copy_dest == COPY_NEW_FE)
+	{
+		/* Shouldn't have any unsent data */
+		Assert(cstate->fe_msgbuf->len == 0);
+		/* Send Copy Done message */
+		pq_putemptymessage('c');
+	}
+	else
+	{
+		CopySendData(cstate, "\\.", 2);
+		/* Need to flush out the trailer (this also appends a newline) */
+		CopySendEndOfRow(cstate);
+		pq_endcopyout(false);
+	}
+}
+
+/*----------
+ * CopySendData sends output data to the destination (file or frontend)
+ * CopySendString does the same for null-terminated strings
+ * CopySendChar does the same for single characters
+ * CopySendEndOfRow does the appropriate thing at end of each data row
+ *	(data is not actually flushed except by CopySendEndOfRow)
+ *
+ * NB: no data conversion is applied by these functions
+ *----------
+ */
+static void
+CopySendData(CopyToState cstate, const void *databuf, int datasize)
+{
+	appendBinaryStringInfo(cstate->fe_msgbuf, databuf, datasize);
+}
+
+static void
+CopySendString(CopyToState cstate, const char *str)
+{
+	appendBinaryStringInfo(cstate->fe_msgbuf, str, strlen(str));
+}
+
+static void
+CopySendChar(CopyToState cstate, char c)
+{
+	appendStringInfoCharMacro(cstate->fe_msgbuf, c);
+}
+
+static void
+CopySendEndOfRow(CopyToState cstate)
+{
+	StringInfo	fe_msgbuf = cstate->fe_msgbuf;
+
+	switch (cstate->copy_dest)
+	{
+		case COPY_FILE:
+			if (!cstate->opts.binary)
+			{
+				/* Default line termination depends on platform */
+#ifndef WIN32
+				CopySendChar(cstate, '\n');
+#else
+				CopySendString(cstate, "\r\n");
+#endif
+			}
+
+			if (fwrite(fe_msgbuf->data, fe_msgbuf->len, 1,
+					   cstate->copy_file) != 1 ||
+				ferror(cstate->copy_file))
+			{
+				if (cstate->is_program)
+				{
+					if (errno == EPIPE)
+					{
+						/*
+						 * The pipe will be closed automatically on error at
+						 * the end of transaction, but we might get a better
+						 * error message from the subprocess' exit code than
+						 * just "Broken Pipe"
+						 */
+						ClosePipeToProgram(cstate);
+
+						/*
+						 * If ClosePipeToProgram() didn't throw an error, the
+						 * program terminated normally, but closed the pipe
+						 * first. Restore errno, and throw an error.
+						 */
+						errno = EPIPE;
+					}
+					ereport(ERROR,
+							(errcode_for_file_access(),
+							 errmsg("could not write to COPY program: %m")));
+				}
+				else
+					ereport(ERROR,
+							(errcode_for_file_access(),
+							 errmsg("could not write to COPY file: %m")));
+			}
+			break;
+		case COPY_OLD_FE:
+			/* The FE/BE protocol uses \n as newline for all platforms */
+			if (!cstate->opts.binary)
+				CopySendChar(cstate, '\n');
+
+			if (pq_putbytes(fe_msgbuf->data, fe_msgbuf->len))
+			{
+				/* no hope of recovering connection sync, so FATAL */
+				ereport(FATAL,
+						(errcode(ERRCODE_CONNECTION_FAILURE),
+						 errmsg("connection lost during COPY to stdout")));
+			}
+			break;
+		case COPY_NEW_FE:
+			/* The FE/BE protocol uses \n as newline for all platforms */
+			if (!cstate->opts.binary)
+				CopySendChar(cstate, '\n');
+
+			/* Dump the accumulated row as one CopyData message */
+			(void) pq_putmessage('d', fe_msgbuf->data, fe_msgbuf->len);
+			break;
+	}
+
+	resetStringInfo(fe_msgbuf);
+}
+
+/*
+ * These functions do apply some data conversion
+ */
+
+/*
+ * CopySendInt32 sends an int32 in network byte order
+ */
+static inline void
+CopySendInt32(CopyToState cstate, int32 val)
+{
+	uint32		buf;
+
+	buf = pg_hton32((uint32) val);
+	CopySendData(cstate, &buf, sizeof(buf));
+}
+
+/*
+ * CopySendInt16 sends an int16 in network byte order
+ */
+static inline void
+CopySendInt16(CopyToState cstate, int16 val)
+{
+	uint16		buf;
+
+	buf = pg_hton16((uint16) val);
+	CopySendData(cstate, &buf, sizeof(buf));
+}
+
+/*
+ * Closes the pipe to an external program, checking the pclose() return code.
+ */
+static void
+ClosePipeToProgram(CopyToState cstate)
+{
+	int			pclose_rc;
+
+	Assert(cstate->is_program);
+
+	pclose_rc = ClosePipeStream(cstate->copy_file);
+	if (pclose_rc == -1)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not close pipe to external command: %m")));
+	else if (pclose_rc != 0)
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("program \"%s\" failed",
+						cstate->filename),
+				 errdetail_internal("%s", wait_result_to_str(pclose_rc))));
+	}
+}
+
+/*
+ * Release resources allocated in a cstate for COPY TO/FROM.
+ */
+static void
+EndCopy(CopyToState cstate)
+{
+	if (cstate->is_program)
+	{
+		ClosePipeToProgram(cstate);
+	}
+	else
+	{
+		if (cstate->filename != NULL && FreeFile(cstate->copy_file))
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not close file \"%s\": %m",
+							cstate->filename)));
+	}
+
+	MemoryContextDelete(cstate->copycontext);
+	pfree(cstate);
+}
+
+/*
+ * Setup CopyToState to read tuples from a table or a query for COPY TO.
+ */
+CopyToState
+BeginCopyTo(ParseState *pstate,
+			Relation rel,
+			RawStmt *raw_query,
+			Oid queryRelId,
+			const char *filename,
+			bool is_program,
+			List *attnamelist,
+			List *options)
+{
+	CopyToState	cstate;
+	bool		pipe = (filename == NULL);
+	TupleDesc	tupDesc;
+	int			num_phys_attrs;
+	MemoryContext oldcontext;
+
+	if (rel != NULL && rel->rd_rel->relkind != RELKIND_RELATION)
+	{
+		if (rel->rd_rel->relkind == RELKIND_VIEW)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from view \"%s\"",
+							RelationGetRelationName(rel)),
+					 errhint("Try the COPY (SELECT ...) TO variant.")));
+		else if (rel->rd_rel->relkind == RELKIND_MATVIEW)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from materialized view \"%s\"",
+							RelationGetRelationName(rel)),
+					 errhint("Try the COPY (SELECT ...) TO variant.")));
+		else if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from foreign table \"%s\"",
+							RelationGetRelationName(rel)),
+					 errhint("Try the COPY (SELECT ...) TO variant.")));
+		else if (rel->rd_rel->relkind == RELKIND_SEQUENCE)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from sequence \"%s\"",
+							RelationGetRelationName(rel))));
+		else if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from partitioned table \"%s\"",
+							RelationGetRelationName(rel)),
+					 errhint("Try the COPY (SELECT ...) TO variant.")));
+		else
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("cannot copy from non-table relation \"%s\"",
+							RelationGetRelationName(rel))));
+	}
+
+
+	/* Allocate workspace and zero all fields */
+	cstate = (CopyToStateData *) palloc0(sizeof(CopyToStateData));
+
+	/*
+	 * We allocate everything used by a cstate in a new memory context. This
+	 * avoids memory leaks during repeated use of COPY in a query.
+	 */
+	cstate->copycontext = AllocSetContextCreate(CurrentMemoryContext,
+												"COPY",
+												ALLOCSET_DEFAULT_SIZES);
+
+	oldcontext = MemoryContextSwitchTo(cstate->copycontext);
+
+	/* Extract options from the statement node tree */
+	ProcessCopyOptions(pstate, &cstate->opts, false /* is_from */, options);
+
+	/* Process the source/target relation or query */
+	if (rel)
+	{
+		Assert(!raw_query);
+
+		cstate->rel = rel;
+
+		tupDesc = RelationGetDescr(cstate->rel);
+	}
+	else
+	{
+		List	   *rewritten;
+		Query	   *query;
+		PlannedStmt *plan;
+		DestReceiver *dest;
+
+		cstate->rel = NULL;
+
+		/*
+		 * Run parse analysis and rewrite.  Note this also acquires sufficient
+		 * locks on the source table(s).
+		 *
+		 * Because the parser and planner tend to scribble on their input, we
+		 * make a preliminary copy of the source querytree.  This prevents
+		 * problems in the case that the COPY is in a portal or plpgsql
+		 * function and is executed repeatedly.  (See also the same hack in
+		 * DECLARE CURSOR and PREPARE.)  XXX FIXME someday.
+		 */
+		rewritten = pg_analyze_and_rewrite(copyObject(raw_query),
+										   pstate->p_sourcetext, NULL, 0,
+										   NULL);
+
+		/* check that we got back something we can work with */
+		if (rewritten == NIL)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("DO INSTEAD NOTHING rules are not supported for COPY")));
+		}
+		else if (list_length(rewritten) > 1)
+		{
+			ListCell   *lc;
+
+			/* examine queries to determine which error message to issue */
+			foreach(lc, rewritten)
+			{
+				Query	   *q = lfirst_node(Query, lc);
+
+				if (q->querySource == QSRC_QUAL_INSTEAD_RULE)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("conditional DO INSTEAD rules are not supported for COPY")));
+				if (q->querySource == QSRC_NON_INSTEAD_RULE)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("DO ALSO rules are not supported for the COPY")));
+			}
+
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("multi-statement DO INSTEAD rules are not supported for COPY")));
+		}
+
+		query = linitial_node(Query, rewritten);
+
+		/* The grammar allows SELECT INTO, but we don't support that */
+		if (query->utilityStmt != NULL &&
+			IsA(query->utilityStmt, CreateTableAsStmt))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("COPY (SELECT INTO) is not supported")));
+
+		Assert(query->utilityStmt == NULL);
+
+		/*
+		 * Similarly the grammar doesn't enforce the presence of a RETURNING
+		 * clause, but this is required here.
+		 */
+		if (query->commandType != CMD_SELECT &&
+			query->returningList == NIL)
+		{
+			Assert(query->commandType == CMD_INSERT ||
+				   query->commandType == CMD_UPDATE ||
+				   query->commandType == CMD_DELETE);
+
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("COPY query must have a RETURNING clause")));
+		}
+
+		/* plan the query */
+		plan = pg_plan_query(query, pstate->p_sourcetext,
+							 CURSOR_OPT_PARALLEL_OK, NULL);
+
+		/*
+		 * With row level security and a user using "COPY relation TO", we
+		 * have to convert the "COPY relation TO" to a query-based COPY (eg:
+		 * "COPY (SELECT * FROM relation) TO"), to allow the rewriter to add
+		 * in any RLS clauses.
+		 *
+		 * When this happens, we are passed in the relid of the originally
+		 * found relation (which we have locked).  As the planner will look up
+		 * the relation again, we double-check here to make sure it found the
+		 * same one that we have locked.
+		 */
+		if (queryRelId != InvalidOid)
+		{
+			/*
+			 * Note that with RLS involved there may be multiple relations,
+			 * and while the one we need is almost certainly first, we don't
+			 * make any guarantees of that in the planner, so check the whole
+			 * list and make sure we find the original relation.
+			 */
+			if (!list_member_oid(plan->relationOids, queryRelId))
+				ereport(ERROR,
+						(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+						 errmsg("relation referenced by COPY statement has changed")));
+		}
+
+		/*
+		 * Use a snapshot with an updated command ID to ensure this query sees
+		 * results of any previously executed queries.
+		 */
+		PushCopiedSnapshot(GetActiveSnapshot());
+		UpdateActiveSnapshotCommandId();
+
+		/* Create dest receiver for COPY OUT */
+		dest = CreateDestReceiver(DestCopyOut);
+		((DR_copy *) dest)->cstate = cstate;
+
+		/* Create a QueryDesc requesting no output */
+		cstate->queryDesc = CreateQueryDesc(plan, pstate->p_sourcetext,
+											GetActiveSnapshot(),
+											InvalidSnapshot,
+											dest, NULL, NULL, 0);
+
+		/*
+		 * Call ExecutorStart to prepare the plan for execution.
+		 *
+		 * ExecutorStart computes a result tupdesc for us
+		 */
+		ExecutorStart(cstate->queryDesc, 0);
+
+		tupDesc = cstate->queryDesc->tupDesc;
+	}
+
+	/* Generate or convert list of attributes to process */
+	cstate->attnumlist = CopyGetAttnums(tupDesc, cstate->rel, attnamelist);
+
+	num_phys_attrs = tupDesc->natts;
+
+	/* Convert FORCE_QUOTE name list to per-column flags, check validity */
+	cstate->opts.force_quote_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+	if (cstate->opts.force_quote_all)
+	{
+		int			i;
+
+		for (i = 0; i < num_phys_attrs; i++)
+			cstate->opts.force_quote_flags[i] = true;
+	}
+	else if (cstate->opts.force_quote)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.force_quote);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg("FORCE_QUOTE column \"%s\" not referenced by COPY",
+								NameStr(attr->attname))));
+			cstate->opts.force_quote_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Convert FORCE_NOT_NULL name list to per-column flags, check validity */
+	cstate->opts.force_notnull_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+	if (cstate->opts.force_notnull)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.force_notnull);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg("FORCE_NOT_NULL column \"%s\" not referenced by COPY",
+								NameStr(attr->attname))));
+			cstate->opts.force_notnull_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Convert FORCE_NULL name list to per-column flags, check validity */
+	cstate->opts.force_null_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
+	if (cstate->opts.force_null)
+	{
+		List	   *attnums;
+		ListCell   *cur;
+
+		attnums = CopyGetAttnums(tupDesc, cstate->rel, cstate->opts.force_null);
+
+		foreach(cur, attnums)
+		{
+			int			attnum = lfirst_int(cur);
+			Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+			if (!list_member_int(cstate->attnumlist, attnum))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+						 errmsg("FORCE_NULL column \"%s\" not referenced by COPY",
+								NameStr(attr->attname))));
+			cstate->opts.force_null_flags[attnum - 1] = true;
+		}
+	}
+
+	/* Use client encoding when ENCODING option is not specified. */
+	if (cstate->opts.file_encoding < 0)
+		cstate->file_encoding = pg_get_client_encoding();
+	else
+		cstate->file_encoding = cstate->opts.file_encoding;
+
+	/*
+	 * Set up encoding conversion info.  Even if the file and server encodings
+	 * are the same, we must apply pg_any_to_server() to validate data in
+	 * multibyte encodings.
+	 */
+	cstate->need_transcoding =
+		(cstate->file_encoding != GetDatabaseEncoding() ||
+		 pg_database_encoding_max_length() > 1);
+	/* See Multibyte encoding comment above */
+	cstate->encoding_embeds_ascii = PG_ENCODING_IS_CLIENT_ONLY(cstate->file_encoding);
+
+	cstate->copy_dest = COPY_FILE;	/* default */
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (pipe)
+	{
+		Assert(!is_program);	/* the grammar does not allow this */
+		if (whereToSendOutput != DestRemote)
+			cstate->copy_file = stdout;
+	}
+	else
+	{
+		cstate->filename = pstrdup(filename);
+		cstate->is_program = is_program;
+
+		if (is_program)
+		{
+			cstate->copy_file = OpenPipeStream(cstate->filename, PG_BINARY_W);
+			if (cstate->copy_file == NULL)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not execute command \"%s\": %m",
+								cstate->filename)));
+		}
+		else
+		{
+			mode_t		oumask; /* Pre-existing umask value */
+			struct stat st;
+
+			/*
+			 * Prevent write to relative path ... too easy to shoot oneself in
+			 * the foot by overwriting a database file ...
+			 */
+			if (!is_absolute_path(filename))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_NAME),
+						 errmsg("relative path not allowed for COPY to file")));
+
+			oumask = umask(S_IWGRP | S_IWOTH);
+			PG_TRY();
+			{
+				cstate->copy_file = AllocateFile(cstate->filename, PG_BINARY_W);
+			}
+			PG_FINALLY();
+			{
+				umask(oumask);
+			}
+			PG_END_TRY();
+			if (cstate->copy_file == NULL)
+			{
+				/* copy errno because ereport subfunctions might change it */
+				int			save_errno = errno;
+
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not open file \"%s\" for writing: %m",
+								cstate->filename),
+						 (save_errno == ENOENT || save_errno == EACCES) ?
+						 errhint("COPY TO instructs the PostgreSQL server process to write a file. "
+								 "You may want a client-side facility such as psql's \\copy.") : 0));
+			}
+
+			if (fstat(fileno(cstate->copy_file), &st))
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not stat file \"%s\": %m",
+								cstate->filename)));
+
+			if (S_ISDIR(st.st_mode))
+				ereport(ERROR,
+						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+						 errmsg("\"%s\" is a directory", cstate->filename)));
+		}
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	return cstate;
+}
+
+/*
+ * This intermediate routine exists mainly to localize the effects of setjmp
+ * so we don't need to plaster a lot of variables with "volatile".
+ */
+uint64
+DoCopyTo(CopyToState cstate)
+{
+	bool		pipe = (cstate->filename == NULL);
+	bool		fe_copy = (pipe && whereToSendOutput == DestRemote);
+	uint64		processed;
+
+	PG_TRY();
+	{
+		if (fe_copy)
+			SendCopyBegin(cstate);
+
+		processed = CopyTo(cstate);
+
+		if (fe_copy)
+			SendCopyEnd(cstate);
+	}
+	PG_CATCH();
+	{
+		/*
+		 * Make sure we turn off old-style COPY OUT mode upon error. It is
+		 * okay to do this in all cases, since it does nothing if the mode is
+		 * not on.
+		 */
+		pq_endcopyout(true);
+		PG_RE_THROW();
+	}
+	PG_END_TRY();
+
+	return processed;
+}
+
+/*
+ * Clean up storage and release resources for COPY TO.
+ */
+void
+EndCopyTo(CopyToState cstate)
+{
+	if (cstate->queryDesc != NULL)
+	{
+		/* Close down the query and free resources. */
+		ExecutorFinish(cstate->queryDesc);
+		ExecutorEnd(cstate->queryDesc);
+		FreeQueryDesc(cstate->queryDesc);
+		PopActiveSnapshot();
+	}
+
+	/* Clean up storage */
+	EndCopy(cstate);
+}
+
+/*
+ * Copy from relation or query TO file.
+ */
+static uint64
+CopyTo(CopyToState cstate)
+{
+	TupleDesc	tupDesc;
+	int			num_phys_attrs;
+	ListCell   *cur;
+	uint64		processed;
+
+	if (cstate->rel)
+		tupDesc = RelationGetDescr(cstate->rel);
+	else
+		tupDesc = cstate->queryDesc->tupDesc;
+	num_phys_attrs = tupDesc->natts;
+	cstate->opts.null_print_client = cstate->opts.null_print; /* default */
+
+	/* We use fe_msgbuf as a per-row buffer regardless of copy_dest */
+	cstate->fe_msgbuf = makeStringInfo();
+
+	/* Get info about the columns we need to process. */
+	cstate->out_functions = (FmgrInfo *) palloc(num_phys_attrs * sizeof(FmgrInfo));
+	foreach(cur, cstate->attnumlist)
+	{
+		int			attnum = lfirst_int(cur);
+		Oid			out_func_oid;
+		bool		isvarlena;
+		Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
+
+		if (cstate->opts.binary)
+			getTypeBinaryOutputInfo(attr->atttypid,
+									&out_func_oid,
+									&isvarlena);
+		else
+			getTypeOutputInfo(attr->atttypid,
+							  &out_func_oid,
+							  &isvarlena);
+		fmgr_info(out_func_oid, &cstate->out_functions[attnum - 1]);
+	}
+
+	/*
+	 * Create a temporary memory context that we can reset once per row to
+	 * recover palloc'd memory.  This avoids any problems with leaks inside
+	 * datatype output routines, and should be faster than retail pfree's
+	 * anyway.  (We don't need a whole econtext as CopyFrom does.)
+	 */
+	cstate->rowcontext = AllocSetContextCreate(CurrentMemoryContext,
+											   "COPY TO",
+											   ALLOCSET_DEFAULT_SIZES);
+
+	if (cstate->opts.binary)
+	{
+		/* Generate header for a binary copy */
+		int32		tmp;
+
+		/* Signature */
+		CopySendData(cstate, BinarySignature, 11);
+		/* Flags field */
+		tmp = 0;
+		CopySendInt32(cstate, tmp);
+		/* No header extension */
+		tmp = 0;
+		CopySendInt32(cstate, tmp);
+	}
+	else
+	{
+		/*
+		 * For non-binary copy, we need to convert null_print to file
+		 * encoding, because it will be sent directly with CopySendString.
+		 */
+		if (cstate->need_transcoding)
+			cstate->opts.null_print_client = pg_server_to_any(cstate->opts.null_print,
+														 cstate->opts.null_print_len,
+														 cstate->file_encoding);
+
+		/* if a header has been requested send the line */
+		if (cstate->opts.header_line)
+		{
+			bool		hdr_delim = false;
+
+			foreach(cur, cstate->attnumlist)
+			{
+				int			attnum = lfirst_int(cur);
+				char	   *colname;
+
+				if (hdr_delim)
+					CopySendChar(cstate, cstate->opts.delim[0]);
+				hdr_delim = true;
+
+				colname = NameStr(TupleDescAttr(tupDesc, attnum - 1)->attname);
+
+				CopyAttributeOutCSV(cstate, colname, false,
+									list_length(cstate->attnumlist) == 1);
+			}
+
+			CopySendEndOfRow(cstate);
+		}
+	}
+
+	if (cstate->rel)
+	{
+		TupleTableSlot *slot;
+		TableScanDesc scandesc;
+
+		scandesc = table_beginscan(cstate->rel, GetActiveSnapshot(), 0, NULL);
+		slot = table_slot_create(cstate->rel, NULL);
+
+		processed = 0;
+		while (table_scan_getnextslot(scandesc, ForwardScanDirection, slot))
+		{
+			CHECK_FOR_INTERRUPTS();
+
+			/* Deconstruct the tuple ... */
+			slot_getallattrs(slot);
+
+			/* Format and send the data */
+			CopyOneRowTo(cstate, slot);
+			processed++;
+		}
+
+		ExecDropSingleTupleTableSlot(slot);
+		table_endscan(scandesc);
+	}
+	else
+	{
+		/* run the plan --- the dest receiver will send tuples */
+		ExecutorRun(cstate->queryDesc, ForwardScanDirection, 0L, true);
+		processed = ((DR_copy *) cstate->queryDesc->dest)->processed;
+	}
+
+	if (cstate->opts.binary)
+	{
+		/* Generate trailer for a binary copy */
+		CopySendInt16(cstate, -1);
+		/* Need to flush out the trailer */
+		CopySendEndOfRow(cstate);
+	}
+
+	MemoryContextDelete(cstate->rowcontext);
+
+	return processed;
+}
+
+/*
+ * Emit one row during CopyTo().
+ */
+static void
+CopyOneRowTo(CopyToState cstate, TupleTableSlot *slot)
+{
+	bool		need_delim = false;
+	FmgrInfo   *out_functions = cstate->out_functions;
+	MemoryContext oldcontext;
+	ListCell   *cur;
+	char	   *string;
+
+	MemoryContextReset(cstate->rowcontext);
+	oldcontext = MemoryContextSwitchTo(cstate->rowcontext);
+
+	if (cstate->opts.binary)
+	{
+		/* Binary per-tuple header */
+		CopySendInt16(cstate, list_length(cstate->attnumlist));
+	}
+
+	/* Make sure the tuple is fully deconstructed */
+	slot_getallattrs(slot);
+
+	foreach(cur, cstate->attnumlist)
+	{
+		int			attnum = lfirst_int(cur);
+		Datum		value = slot->tts_values[attnum - 1];
+		bool		isnull = slot->tts_isnull[attnum - 1];
+
+		if (!cstate->opts.binary)
+		{
+			if (need_delim)
+				CopySendChar(cstate, cstate->opts.delim[0]);
+			need_delim = true;
+		}
+
+		if (isnull)
+		{
+			if (!cstate->opts.binary)
+				CopySendString(cstate, cstate->opts.null_print_client);
+			else
+				CopySendInt32(cstate, -1);
+		}
+		else
+		{
+			if (!cstate->opts.binary)
+			{
+				string = OutputFunctionCall(&out_functions[attnum - 1],
+											value);
+				if (cstate->opts.csv_mode)
+					CopyAttributeOutCSV(cstate, string,
+										cstate->opts.force_quote_flags[attnum - 1],
+										list_length(cstate->attnumlist) == 1);
+				else
+					CopyAttributeOutText(cstate, string);
+			}
+			else
+			{
+				bytea	   *outputbytes;
+
+				outputbytes = SendFunctionCall(&out_functions[attnum - 1],
+											   value);
+				CopySendInt32(cstate, VARSIZE(outputbytes) - VARHDRSZ);
+				CopySendData(cstate, VARDATA(outputbytes),
+							 VARSIZE(outputbytes) - VARHDRSZ);
+			}
+		}
+	}
+
+	CopySendEndOfRow(cstate);
+
+	MemoryContextSwitchTo(oldcontext);
+}
+
+/*
+ * Send text representation of one attribute, with conversion and escaping
+ */
+#define DUMPSOFAR() \
+	do { \
+		if (ptr > start) \
+			CopySendData(cstate, start, ptr - start); \
+	} while (0)
+
+static void
+CopyAttributeOutText(CopyToState cstate, char *string)
+{
+	char	   *ptr;
+	char	   *start;
+	char		c;
+	char		delimc = cstate->opts.delim[0];
+
+	if (cstate->need_transcoding)
+		ptr = pg_server_to_any(string, strlen(string), cstate->file_encoding);
+	else
+		ptr = string;
+
+	/*
+	 * We have to grovel through the string searching for control characters
+	 * and instances of the delimiter character.  In most cases, though, these
+	 * are infrequent.  To avoid overhead from calling CopySendData once per
+	 * character, we dump out all characters between escaped characters in a
+	 * single call.  The loop invariant is that the data from "start" to "ptr"
+	 * can be sent literally, but hasn't yet been.
+	 *
+	 * We can skip pg_encoding_mblen() overhead when encoding is safe, because
+	 * in valid backend encodings, extra bytes of a multibyte character never
+	 * look like ASCII.  This loop is sufficiently performance-critical that
+	 * it's worth making two copies of it to get the IS_HIGHBIT_SET() test out
+	 * of the normal safe-encoding path.
+	 */
+	if (cstate->encoding_embeds_ascii)
+	{
+		start = ptr;
+		while ((c = *ptr) != '\0')
+		{
+			if ((unsigned char) c < (unsigned char) 0x20)
+			{
+				/*
+				 * \r and \n must be escaped, the others are traditional. We
+				 * prefer to dump these using the C-like notation, rather than
+				 * a backslash and the literal character, because it makes the
+				 * dump file a bit more proof against Microsoftish data
+				 * mangling.
+				 */
+				switch (c)
+				{
+					case '\b':
+						c = 'b';
+						break;
+					case '\f':
+						c = 'f';
+						break;
+					case '\n':
+						c = 'n';
+						break;
+					case '\r':
+						c = 'r';
+						break;
+					case '\t':
+						c = 't';
+						break;
+					case '\v':
+						c = 'v';
+						break;
+					default:
+						/* If it's the delimiter, must backslash it */
+						if (c == delimc)
+							break;
+						/* All ASCII control chars are length 1 */
+						ptr++;
+						continue;	/* fall to end of loop */
+				}
+				/* if we get here, we need to convert the control char */
+				DUMPSOFAR();
+				CopySendChar(cstate, '\\');
+				CopySendChar(cstate, c);
+				start = ++ptr;	/* do not include char in next run */
+			}
+			else if (c == '\\' || c == delimc)
+			{
+				DUMPSOFAR();
+				CopySendChar(cstate, '\\');
+				start = ptr++;	/* we include char in next run */
+			}
+			else if (IS_HIGHBIT_SET(c))
+				ptr += pg_encoding_mblen(cstate->file_encoding, ptr);
+			else
+				ptr++;
+		}
+	}
+	else
+	{
+		start = ptr;
+		while ((c = *ptr) != '\0')
+		{
+			if ((unsigned char) c < (unsigned char) 0x20)
+			{
+				/*
+				 * \r and \n must be escaped, the others are traditional. We
+				 * prefer to dump these using the C-like notation, rather than
+				 * a backslash and the literal character, because it makes the
+				 * dump file a bit more proof against Microsoftish data
+				 * mangling.
+				 */
+				switch (c)
+				{
+					case '\b':
+						c = 'b';
+						break;
+					case '\f':
+						c = 'f';
+						break;
+					case '\n':
+						c = 'n';
+						break;
+					case '\r':
+						c = 'r';
+						break;
+					case '\t':
+						c = 't';
+						break;
+					case '\v':
+						c = 'v';
+						break;
+					default:
+						/* If it's the delimiter, must backslash it */
+						if (c == delimc)
+							break;
+						/* All ASCII control chars are length 1 */
+						ptr++;
+						continue;	/* fall to end of loop */
+				}
+				/* if we get here, we need to convert the control char */
+				DUMPSOFAR();
+				CopySendChar(cstate, '\\');
+				CopySendChar(cstate, c);
+				start = ++ptr;	/* do not include char in next run */
+			}
+			else if (c == '\\' || c == delimc)
+			{
+				DUMPSOFAR();
+				CopySendChar(cstate, '\\');
+				start = ptr++;	/* we include char in next run */
+			}
+			else
+				ptr++;
+		}
+	}
+
+	DUMPSOFAR();
+}
+
+/*
+ * Send text representation of one attribute, with conversion and
+ * CSV-style escaping
+ */
+static void
+CopyAttributeOutCSV(CopyToState cstate, char *string,
+					bool use_quote, bool single_attr)
+{
+	char	   *ptr;
+	char	   *start;
+	char		c;
+	char		delimc = cstate->opts.delim[0];
+	char		quotec = cstate->opts.quote[0];
+	char		escapec = cstate->opts.escape[0];
+
+	/* force quoting if it matches null_print (before conversion!) */
+	if (!use_quote && strcmp(string, cstate->opts.null_print) == 0)
+		use_quote = true;
+
+	if (cstate->need_transcoding)
+		ptr = pg_server_to_any(string, strlen(string), cstate->file_encoding);
+	else
+		ptr = string;
+
+	/*
+	 * Make a preliminary pass to discover if it needs quoting
+	 */
+	if (!use_quote)
+	{
+		/*
+		 * Because '\.' can be a data value, quote it if it appears alone on a
+		 * line so it is not interpreted as the end-of-data marker.
+		 */
+		if (single_attr && strcmp(ptr, "\\.") == 0)
+			use_quote = true;
+		else
+		{
+			char	   *tptr = ptr;
+
+			while ((c = *tptr) != '\0')
+			{
+				if (c == delimc || c == quotec || c == '\n' || c == '\r')
+				{
+					use_quote = true;
+					break;
+				}
+				if (IS_HIGHBIT_SET(c) && cstate->encoding_embeds_ascii)
+					tptr += pg_encoding_mblen(cstate->file_encoding, tptr);
+				else
+					tptr++;
+			}
+		}
+	}
+
+	if (use_quote)
+	{
+		CopySendChar(cstate, quotec);
+
+		/*
+		 * We adopt the same optimization strategy as in CopyAttributeOutText
+		 */
+		start = ptr;
+		while ((c = *ptr) != '\0')
+		{
+			if (c == quotec || c == escapec)
+			{
+				DUMPSOFAR();
+				CopySendChar(cstate, escapec);
+				start = ptr;	/* we include char in next run */
+			}
+			if (IS_HIGHBIT_SET(c) && cstate->encoding_embeds_ascii)
+				ptr += pg_encoding_mblen(cstate->file_encoding, ptr);
+			else
+				ptr++;
+		}
+		DUMPSOFAR();
+
+		CopySendChar(cstate, quotec);
+	}
+	else
+	{
+		/* If it doesn't need quoting, we can just dump it as-is */
+		CopySendString(cstate, ptr);
+	}
+}
+
+/*
+ * copy_dest_startup --- executor startup
+ */
+static void
+copy_dest_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
+{
+	/* no-op */
+}
+
+/*
+ * copy_dest_receive --- receive one tuple
+ */
+static bool
+copy_dest_receive(TupleTableSlot *slot, DestReceiver *self)
+{
+	DR_copy    *myState = (DR_copy *) self;
+	CopyToState	cstate = myState->cstate;
+
+	/* Send the data */
+	CopyOneRowTo(cstate, slot);
+	myState->processed++;
+
+	return true;
+}
+
+/*
+ * copy_dest_shutdown --- executor end
+ */
+static void
+copy_dest_shutdown(DestReceiver *self)
+{
+	/* no-op */
+}
+
+/*
+ * copy_dest_destroy --- release DestReceiver object
+ */
+static void
+copy_dest_destroy(DestReceiver *self)
+{
+	pfree(self);
+}
+
+/*
+ * CreateCopyDestReceiver -- create a suitable DestReceiver object
+ */
+DestReceiver *
+CreateCopyDestReceiver(void)
+{
+	DR_copy    *self = (DR_copy *) palloc(sizeof(DR_copy));
+
+	self->pub.receiveSlot = copy_dest_receive;
+	self->pub.rStartup = copy_dest_startup;
+	self->pub.rShutdown = copy_dest_shutdown;
+	self->pub.rDestroy = copy_dest_destroy;
+	self->pub.mydest = DestCopyOut;
+
+	self->cstate = NULL;		/* will be set later */
+	self->processed = 0;
+
+	return (DestReceiver *) self;
+}

src/backend/replication/logical/tablesync.c

@@ -749,7 +749,7 @@ copy_table(Relation rel)
 	LogicalRepRelation lrel;
 	WalRcvExecResult *res;
 	StringInfoData cmd;
-	CopyState	cstate;
+	CopyFromState cstate;
 	List	   *attnamelist;
 	ParseState *pstate;
 
@@ -800,7 +800,7 @@ copy_table(Relation rel)
 										 NULL, false, false);
 
 	attnamelist = make_copy_attnamelist(relmapentry);
-	cstate = BeginCopyFrom(pstate, rel, NULL, false, copy_read_data, attnamelist, NIL);
+	cstate = BeginCopyFrom(pstate, rel, NULL, NULL, false, copy_read_data, attnamelist, NIL);
 
 	/* Do the copy */
 	(void) CopyFrom(cstate);

src/include/commands/copy.h

@@ -19,26 +19,71 @@
 #include "parser/parse_node.h"
 #include "tcop/dest.h"
 
-/* CopyStateData is private in commands/copy.c */
-typedef struct CopyStateData *CopyState;
+/*
+ * A struct to hold COPY options, in a parsed form. All of these are related
+ * to formatting, except for 'freeze', which doesn't really belong here, but
+ * it's expedient to parse it along with all the other options.
+ */
+typedef struct CopyFormatOptions
+{
+	/* parameters from the COPY command */
+	int			file_encoding;	/* file or remote side's character encoding,
+								 * -1 if not specified */
+	bool		binary;			/* binary format? */
+	bool		freeze;			/* freeze rows on loading? */
+	bool		csv_mode;		/* Comma Separated Value format? */
+	bool		header_line;	/* CSV header line? */
+	char	   *null_print;		/* NULL marker string (server encoding!) */
+	int			null_print_len; /* length of same */
+	char	   *null_print_client;	/* same converted to file encoding */
+	char	   *delim;			/* column delimiter (must be 1 byte) */
+	char	   *quote;			/* CSV quote char (must be 1 byte) */
+	char	   *escape;			/* CSV escape char (must be 1 byte) */
+	List	   *force_quote;	/* list of column names */
+	bool		force_quote_all;	/* FORCE_QUOTE *? */
+	bool	   *force_quote_flags;	/* per-column CSV FQ flags */
+	List	   *force_notnull;	/* list of column names */
+	bool	   *force_notnull_flags;	/* per-column CSV FNN flags */
+	List	   *force_null;		/* list of column names */
+	bool	   *force_null_flags;	/* per-column CSV FN flags */
+	bool		convert_selectively;	/* do selective binary conversion? */
+	List	   *convert_select; /* list of column names (can be NIL) */
+} CopyFormatOptions;
+
+/* These are private in commands/copy[from|to].c */
+typedef struct CopyFromStateData *CopyFromState;
+typedef struct CopyToStateData *CopyToState;
+
 typedef int (*copy_data_source_cb) (void *outbuf, int minread, int maxread);
 
 extern void DoCopy(ParseState *state, const CopyStmt *stmt,
 				   int stmt_location, int stmt_len,
 				   uint64 *processed);
 
-extern void ProcessCopyOptions(ParseState *pstate, CopyState cstate, bool is_from, List *options);
-extern CopyState BeginCopyFrom(ParseState *pstate, Relation rel, const char *filename,
+extern void ProcessCopyOptions(ParseState *pstate, CopyFormatOptions *ops_out, bool is_from, List *options);
+extern CopyFromState BeginCopyFrom(ParseState *pstate, Relation rel, Node *whereClause,
+							   const char *filename,
 							   bool is_program, copy_data_source_cb data_source_cb, List *attnamelist, List *options);
-extern void EndCopyFrom(CopyState cstate);
-extern bool NextCopyFrom(CopyState cstate, ExprContext *econtext,
+extern void EndCopyFrom(CopyFromState cstate);
+extern bool NextCopyFrom(CopyFromState cstate, ExprContext *econtext,
 						 Datum *values, bool *nulls);
-extern bool NextCopyFromRawFields(CopyState cstate,
+extern bool NextCopyFromRawFields(CopyFromState cstate,
 								  char ***fields, int *nfields);
 extern void CopyFromErrorCallback(void *arg);
 
-extern uint64 CopyFrom(CopyState cstate);
+extern uint64 CopyFrom(CopyFromState cstate);
 
 extern DestReceiver *CreateCopyDestReceiver(void);
 
+/*
+ * internal prototypes
+ */
+extern CopyToState BeginCopyTo(ParseState *pstate, Relation rel, RawStmt *query,
+							   Oid queryRelId, const char *filename, bool is_program,
+							   List *attnamelist, List *options);
+extern void EndCopyTo(CopyToState cstate);
+extern uint64 DoCopyTo(CopyToState cstate);
+extern List *CopyGetAttnums(TupleDesc tupDesc, Relation rel,
+							List *attnamelist);
+
 #endif							/* COPY_H */

src/include/commands/copyfrom_internal.h

+/*-------------------------------------------------------------------------
+ *
+ * copyfrom_internal.h
+ *	  Internal definitions for COPY FROM command.
+ *
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/commands/copyfrom_internal.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef COPYFROM_INTERNAL_H
+#define COPYFROM_INTERNAL_H
+
+#include "commands/copy.h"
+#include "commands/trigger.h"
+
+/*
+ * Represents the different source cases we need to worry about at
+ * the bottom level
+ */
+typedef enum CopySource
+{
+	COPY_FILE,					/* from file (or a piped program) */
+	COPY_OLD_FE,				/* from frontend (2.0 protocol) */
+	COPY_NEW_FE,				/* from frontend (3.0 protocol) */
+	COPY_CALLBACK				/* from callback function */
+} CopySource;
+
+/*
+ *	Represents the end-of-line terminator type of the input
+ */
+typedef enum EolType
+{
+	EOL_UNKNOWN,
+	EOL_NL,
+	EOL_CR,
+	EOL_CRNL
+} EolType;
+
+/*
+ * Represents the heap insert method to be used during COPY FROM.
+ */
+typedef enum CopyInsertMethod
+{
+	CIM_SINGLE,					/* use table_tuple_insert or fdw routine */
+	CIM_MULTI,					/* always use table_multi_insert */
+	CIM_MULTI_CONDITIONAL		/* use table_multi_insert only if valid */
+} CopyInsertMethod;
+
+/*
+ * This struct contains all the state variables used throughout a COPY FROM
+ * operation.
+ *
+ * Multi-byte encodings: all supported client-side encodings encode multi-byte
+ * characters by having the first byte's high bit set. Subsequent bytes of the
+ * character can have the high bit not set. When scanning data in such an
+ * encoding to look for a match to a single-byte (ie ASCII) character, we must
+ * use the full pg_encoding_mblen() machinery to skip over multibyte
+ * characters, else we might find a false match to a trailing byte. In
+ * supported server encodings, there is no possibility of a false match, and
+ * it's faster to make useless comparisons to trailing bytes than it is to
+ * invoke pg_encoding_mblen() to skip over them. encoding_embeds_ascii is true
+ * when we have to do it the hard way.
+ */
+typedef struct CopyFromStateData
+{
+	/* low-level state data */
+	CopySource	copy_src;		/* type of copy source */
+	FILE	   *copy_file;		/* used if copy_src == COPY_FILE */
+	StringInfo	fe_msgbuf;		/* used if copy_src == COPY_NEW_FE */
+	bool		reached_eof;	/* true if we read to end of copy data (not
+								 * all copy_src types maintain this) */
+
+	EolType		eol_type;		/* EOL type of input */
+	int			file_encoding;	/* file or remote side's character encoding */
+	bool		need_transcoding;	/* file encoding diff from server? */
+	bool		encoding_embeds_ascii;	/* ASCII can be non-first byte? */
+
+	/* parameters from the COPY command */
+	Relation	rel;			/* relation to copy from */
+	List	   *attnumlist;		/* integer list of attnums to copy */
+	char	   *filename;		/* filename, or NULL for STDIN */
+	bool		is_program;		/* is 'filename' a program to popen? */
+	copy_data_source_cb data_source_cb; /* function for reading data */
+
+	CopyFormatOptions opts;
+	bool	   *convert_select_flags;	/* per-column CSV/TEXT CS flags */
+	Node	   *whereClause;	/* WHERE condition (or NULL) */
+
+	/* these are just for error messages, see CopyFromErrorCallback */
+	const char *cur_relname;	/* table name for error messages */
+	uint64		cur_lineno;		/* line number for error messages */
+	const char *cur_attname;	/* current att for error messages */
+	const char *cur_attval;		/* current att value for error messages */
+
+	/*
+	 * Working state
+	 */
+	MemoryContext copycontext;	/* per-copy execution context */
+
+	AttrNumber	num_defaults;
+	FmgrInfo   *in_functions;	/* array of input functions for each attrs */
+	Oid		   *typioparams;	/* array of element types for in_functions */
+	int		   *defmap;			/* array of default att numbers */
+	ExprState **defexprs;		/* array of default att expressions */
+	bool		volatile_defexprs;	/* is any of defexprs volatile? */
+	List	   *range_table;
+	ExprState  *qualexpr;
+
+	TransitionCaptureState *transition_capture;
+
+	/*
+	 * These variables are used to reduce overhead in COPY FROM.
+	 *
+	 * attribute_buf holds the separated, de-escaped text for each field of
+	 * the current line.  The CopyReadAttributes functions return arrays of
+	 * pointers into this buffer.  We avoid palloc/pfree overhead by re-using
+	 * the buffer on each cycle.
+	 *
+	 * In binary COPY FROM, attribute_buf holds the binary data for the
+	 * current field, but the usage is otherwise similar.
+	 */
+	StringInfoData attribute_buf;
+
+	/* field raw data pointers found by COPY FROM */
+
+	int			max_fields;
+	char	  **raw_fields;
+
+	/*
+	 * Similarly, line_buf holds the whole input line being processed. The
+	 * input cycle is first to read the whole line into line_buf, convert it
+	 * to server encoding there, and then extract the individual attribute
+	 * fields into attribute_buf.  line_buf is preserved unmodified so that we
+	 * can display it in error messages if appropriate.  (In binary mode,
+	 * line_buf is not used.)
+	 */
+	StringInfoData line_buf;
+	bool		line_buf_converted; /* converted to server encoding? */
+	bool		line_buf_valid; /* contains the row being processed? */
+
+	/*
+	 * Finally, raw_buf holds raw data read from the data source (file or
+	 * client connection).  In text mode, CopyReadLine parses this data
+	 * sufficiently to locate line boundaries, then transfers the data to
+	 * line_buf and converts it.  In binary mode, CopyReadBinaryData fetches
+	 * appropriate amounts of data from this buffer.  In both modes, we
+	 * guarantee that there is a \0 at raw_buf[raw_buf_len].
+	 */
+#define RAW_BUF_SIZE 65536		/* we palloc RAW_BUF_SIZE+1 bytes */
+	char	   *raw_buf;
+	int			raw_buf_index;	/* next byte to process */
+	int			raw_buf_len;	/* total # of bytes stored */
+	/* Shorthand for number of unconsumed bytes available in raw_buf */
+#define RAW_BUF_BYTES(cstate) ((cstate)->raw_buf_len - (cstate)->raw_buf_index)
+} CopyFromStateData;
+
+extern void ReceiveCopyBegin(CopyFromState cstate);
+extern void ReceiveCopyBinaryHeader(CopyFromState cstate);
+
+#endif							/* COPYFROM_INTERNAL_H */