Represent command completion tags as structs

The backend was using strings to represent command tags and doing string
comparisons in multiple places, but that's slow and unhelpful.  Create a
new command list with a supporting structure to use instead; this is
stored in a tag-list-file that can be tailored to specific purposes with
a caller-definable C macro, similar to what we do for WAL resource
managers.  The first first such uses are a new CommandTag enum and a
CommandTagBehavior struct.

Replace numerous occurrences of char *completionTag with a
QueryCompletion struct so that the code no longer stores information
about completed queries in a cstring.  Only at the last moment, in
EndCommand(), does this get converted to a string.

EventTriggerCacheItem no longer holds an array of palloc’d tag strings
in sorted order, but rather just a Bitmapset over the CommandTags.

Author: Mark Dilger, with unsolicited help from Álvaro Herrera
Reviewed-by: John Naylor, Tom Lane
Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com

contrib/pg_stat_statements/pg_stat_statements.c

@@ -307,7 +307,7 @@ static void pgss_ExecutorEnd(QueryDesc *queryDesc);
 static void pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 								ProcessUtilityContext context, ParamListInfo params,
 								QueryEnvironment *queryEnv,
-								DestReceiver *dest, char *completionTag);
+								DestReceiver *dest, QueryCompletion *qc);
 static uint64 pgss_hash_string(const char *str, int len);
 static void pgss_store(const char *query, uint64 queryId,
 					   int query_location, int query_len,
@@ -960,7 +960,7 @@ static void
 pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 					ProcessUtilityContext context,
 					ParamListInfo params, QueryEnvironment *queryEnv,
-					DestReceiver *dest, char *completionTag)
+					DestReceiver *dest, QueryCompletion *qc)
 {
 	Node	   *parsetree = pstmt->utilityStmt;
 
@@ -998,11 +998,11 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 			if (prev_ProcessUtility)
 				prev_ProcessUtility(pstmt, queryString,
 									context, params, queryEnv,
-									dest, completionTag);
+									dest, qc);
 			else
 				standard_ProcessUtility(pstmt, queryString,
 										context, params, queryEnv,
-										dest, completionTag);
+										dest, qc);
 		}
 		PG_FINALLY();
 		{
@@ -1013,12 +1013,8 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 		INSTR_TIME_SET_CURRENT(duration);
 		INSTR_TIME_SUBTRACT(duration, start);
 
-		/* parse command tag to retrieve the number of affected rows. */
-		if (completionTag &&
-			strncmp(completionTag, "COPY ", 5) == 0)
-			rows = pg_strtouint64(completionTag + 5, NULL, 10);
-		else
-			rows = 0;
+		if (qc)
+			rows = qc->commandTag == CMDTAG_COPY ? qc->nprocessed : 0;
 
 		/* calc differences of buffer counters. */
 		bufusage.shared_blks_hit =
@@ -1060,11 +1056,11 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 		if (prev_ProcessUtility)
 			prev_ProcessUtility(pstmt, queryString,
 								context, params, queryEnv,
-								dest, completionTag);
+								dest, qc);
 		else
 			standard_ProcessUtility(pstmt, queryString,
 									context, params, queryEnv,
-									dest, completionTag);
+									dest, qc);
 	}
 }
 

contrib/sepgsql/hooks.c

@@ -317,7 +317,7 @@ sepgsql_utility_command(PlannedStmt *pstmt,
 						ParamListInfo params,
 						QueryEnvironment *queryEnv,
 						DestReceiver *dest,
-						char *completionTag)
+						QueryCompletion *qc)
 {
 	Node	   *parsetree = pstmt->utilityStmt;
 	sepgsql_context_info_t saved_context_info = sepgsql_context_info;
@@ -380,11 +380,11 @@ sepgsql_utility_command(PlannedStmt *pstmt,
 		if (next_ProcessUtility_hook)
 			(*next_ProcessUtility_hook) (pstmt, queryString,
 										 context, params, queryEnv,
-										 dest, completionTag);
+										 dest, qc);
 		else
 			standard_ProcessUtility(pstmt, queryString,
 									context, params, queryEnv,
-									dest, completionTag);
+									dest, qc);
 	}
 	PG_FINALLY();
 	{

doc/src/sgml/event-trigger.sgml

@@ -1074,7 +1074,7 @@ typedef struct EventTriggerData
     NodeTag     type;
     const char *event;      /* event name */
     Node       *parsetree;  /* parse tree */
-    const char *tag;        /* command tag */
+    CommandTag  tag;        /* command tag */
 } EventTriggerData;
 </programlisting>
 

src/backend/commands/createas.c

@@ -10,7 +10,7 @@
  *
  * Formerly, CTAS was implemented as a variant of SELECT, which led
  * to assorted legacy behaviors that we still try to preserve, notably that
- * we must return a tuples-processed count in the completionTag.  (We no
+ * we must return a tuples-processed count in the QueryCompletion.  (We no
  * longer do that for CTAS ... WITH NO DATA, however.)
  *
  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
@@ -225,7 +225,7 @@ create_ctas_nodata(List *tlist, IntoClause *into)
 ObjectAddress
 ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 				  ParamListInfo params, QueryEnvironment *queryEnv,
-				  char *completionTag)
+				  QueryCompletion *qc)
 {
 	Query	   *query = castNode(Query, stmt->query);
 	IntoClause *into = stmt->into;
@@ -270,7 +270,7 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 		ExecuteStmt *estmt = castNode(ExecuteStmt, query->utilityStmt);
 
 		Assert(!is_matview);	/* excluded by syntax */
-		ExecuteQuery(pstate, estmt, into, params, dest, completionTag);
+		ExecuteQuery(pstate, estmt, into, params, dest, qc);
 
 		/* get object address that intorel_startup saved for us */
 		address = ((DR_intorel *) dest)->reladdr;
@@ -352,11 +352,9 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 		/* run the plan to completion */
 		ExecutorRun(queryDesc, ForwardScanDirection, 0L, true);
 
-		/* save the rowcount if we're given a completionTag to fill */
-		if (completionTag)
-			snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-					 "SELECT " UINT64_FORMAT,
-					 queryDesc->estate->es_processed);
+		/* save the rowcount if we're given a qc to fill */
+		if (qc)
+			SetQueryCompletion(qc, CMDTAG_SELECT, queryDesc->estate->es_processed);
 
 		/* get object address that intorel_startup saved for us */
 		address = ((DR_intorel *) dest)->reladdr;

src/backend/commands/event_trigger.c

@@ -78,59 +78,6 @@ typedef struct
 	bool		supported;
 } event_trigger_support_data;
 
-typedef enum
-{
-	EVENT_TRIGGER_COMMAND_TAG_OK,
-	EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED,
-	EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED
-} event_trigger_command_tag_check_result;
-
-/* XXX merge this with ObjectTypeMap? */
-static const event_trigger_support_data event_trigger_support[] = {
-	{"ACCESS METHOD", true},
-	{"AGGREGATE", true},
-	{"CAST", true},
-	{"CONSTRAINT", true},
-	{"COLLATION", true},
-	{"CONVERSION", true},
-	{"DATABASE", false},
-	{"DOMAIN", true},
-	{"EXTENSION", true},
-	{"EVENT TRIGGER", false},
-	{"FOREIGN DATA WRAPPER", true},
-	{"FOREIGN TABLE", true},
-	{"FUNCTION", true},
-	{"INDEX", true},
-	{"LANGUAGE", true},
-	{"MATERIALIZED VIEW", true},
-	{"OPERATOR", true},
-	{"OPERATOR CLASS", true},
-	{"OPERATOR FAMILY", true},
-	{"POLICY", true},
-	{"PROCEDURE", true},
-	{"PUBLICATION", true},
-	{"ROLE", false},
-	{"ROUTINE", true},
-	{"RULE", true},
-	{"SCHEMA", true},
-	{"SEQUENCE", true},
-	{"SERVER", true},
-	{"STATISTICS", true},
-	{"SUBSCRIPTION", true},
-	{"TABLE", true},
-	{"TABLESPACE", false},
-	{"TRANSFORM", true},
-	{"TRIGGER", true},
-	{"TEXT SEARCH CONFIGURATION", true},
-	{"TEXT SEARCH DICTIONARY", true},
-	{"TEXT SEARCH PARSER", true},
-	{"TEXT SEARCH TEMPLATE", true},
-	{"TYPE", true},
-	{"USER MAPPING", true},
-	{"VIEW", true},
-	{NULL, false}
-};
-
 /* Support for dropped objects */
 typedef struct SQLDropObject
 {
@@ -150,8 +97,6 @@ typedef struct SQLDropObject
 static void AlterEventTriggerOwner_internal(Relation rel,
 											HeapTuple tup,
 											Oid newOwnerId);
-static event_trigger_command_tag_check_result check_ddl_tag(const char *tag);
-static event_trigger_command_tag_check_result check_table_rewrite_ddl_tag(const char *tag);
 static void error_duplicate_filter_variable(const char *defname);
 static Datum filter_list_to_array(List *filterlist);
 static Oid	insert_event_trigger_tuple(const char *trigname, const char *eventname,
@@ -259,71 +204,23 @@ validate_ddl_tags(const char *filtervar, List *taglist)
 
 	foreach(lc, taglist)
 	{
-		const char *tag = strVal(lfirst(lc));
-		event_trigger_command_tag_check_result result;
+		const char *tagstr = strVal(lfirst(lc));
+		CommandTag	commandTag = GetCommandTagEnum(tagstr);
 
-		result = check_ddl_tag(tag);
-		if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED)
+		if (commandTag == CMDTAG_UNKNOWN)
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 					 errmsg("filter value \"%s\" not recognized for filter variable \"%s\"",
-							tag, filtervar)));
-		if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED)
+							tagstr, filtervar)));
+		if (!command_tag_event_trigger_ok(commandTag))
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 			/* translator: %s represents an SQL statement name */
 					 errmsg("event triggers are not supported for %s",
-							tag)));
+							tagstr)));
 	}
 }
 
-static event_trigger_command_tag_check_result
-check_ddl_tag(const char *tag)
-{
-	const char *obtypename;
-	const event_trigger_support_data *etsd;
-
-	/*
-	 * Handle some idiosyncratic special cases.
-	 */
-	if (pg_strcasecmp(tag, "CREATE TABLE AS") == 0 ||
-		pg_strcasecmp(tag, "SELECT INTO") == 0 ||
-		pg_strcasecmp(tag, "REFRESH MATERIALIZED VIEW") == 0 ||
-		pg_strcasecmp(tag, "ALTER DEFAULT PRIVILEGES") == 0 ||
-		pg_strcasecmp(tag, "ALTER LARGE OBJECT") == 0 ||
-		pg_strcasecmp(tag, "COMMENT") == 0 ||
-		pg_strcasecmp(tag, "GRANT") == 0 ||
-		pg_strcasecmp(tag, "REVOKE") == 0 ||
-		pg_strcasecmp(tag, "DROP OWNED") == 0 ||
-		pg_strcasecmp(tag, "IMPORT FOREIGN SCHEMA") == 0 ||
-		pg_strcasecmp(tag, "SECURITY LABEL") == 0)
-		return EVENT_TRIGGER_COMMAND_TAG_OK;
-
-	/*
-	 * Otherwise, command should be CREATE, ALTER, or DROP.
-	 */
-	if (pg_strncasecmp(tag, "CREATE ", 7) == 0)
-		obtypename = tag + 7;
-	else if (pg_strncasecmp(tag, "ALTER ", 6) == 0)
-		obtypename = tag + 6;
-	else if (pg_strncasecmp(tag, "DROP ", 5) == 0)
-		obtypename = tag + 5;
-	else
-		return EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED;
-
-	/*
-	 * ...and the object type should be something recognizable.
-	 */
-	for (etsd = event_trigger_support; etsd->obtypename != NULL; etsd++)
-		if (pg_strcasecmp(etsd->obtypename, obtypename) == 0)
-			break;
-	if (etsd->obtypename == NULL)
-		return EVENT_TRIGGER_COMMAND_TAG_NOT_RECOGNIZED;
-	if (!etsd->supported)
-		return EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED;
-	return EVENT_TRIGGER_COMMAND_TAG_OK;
-}
-
 /*
  * Validate DDL command tags for event table_rewrite.
  */
@@ -334,29 +231,18 @@ validate_table_rewrite_tags(const char *filtervar, List *taglist)
 
 	foreach(lc, taglist)
 	{
-		const char *tag = strVal(lfirst(lc));
-		event_trigger_command_tag_check_result result;
+		const char *tagstr = strVal(lfirst(lc));
+		CommandTag	commandTag = GetCommandTagEnum(tagstr);
 
-		result = check_table_rewrite_ddl_tag(tag);
-		if (result == EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED)
+		if (!command_tag_table_rewrite_ok(commandTag))
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 			/* translator: %s represents an SQL statement name */
 					 errmsg("event triggers are not supported for %s",
-							tag)));
+							tagstr)));
 	}
 }
 
-static event_trigger_command_tag_check_result
-check_table_rewrite_ddl_tag(const char *tag)
-{
-	if (pg_strcasecmp(tag, "ALTER TABLE") == 0 ||
-		pg_strcasecmp(tag, "ALTER TYPE") == 0)
-		return EVENT_TRIGGER_COMMAND_TAG_OK;
-
-	return EVENT_TRIGGER_COMMAND_TAG_NOT_SUPPORTED;
-}
-
 /*
  * Complain about a duplicate filter variable.
  */
@@ -663,7 +549,7 @@ get_event_trigger_oid(const char *trigname, bool missing_ok)
  * tags matching.
  */
 static bool
-filter_event_trigger(const char **tag, EventTriggerCacheItem *item)
+filter_event_trigger(CommandTag tag, EventTriggerCacheItem *item)
 {
 	/*
 	 * Filter by session replication role, knowing that we never see disabled
@@ -681,9 +567,7 @@ filter_event_trigger(const char **tag, EventTriggerCacheItem *item)
 	}
 
 	/* Filter by tags, if any were specified. */
-	if (item->ntags != 0 && bsearch(tag, item->tag,
-									item->ntags, sizeof(char *),
-									pg_qsort_strcmp) == NULL)
+	if (!bms_is_empty(item->tagset) && !bms_is_member(tag, item->tagset))
 		return false;
 
 	/* if we reach that point, we're not filtering out this item */
@@ -700,7 +584,7 @@ EventTriggerCommonSetup(Node *parsetree,
 						EventTriggerEvent event, const char *eventstr,
 						EventTriggerData *trigdata)
 {
-	const char *tag;
+	CommandTag	tag;
 	List	   *cachelist;
 	ListCell   *lc;
 	List	   *runlist = NIL;
@@ -716,25 +600,25 @@ EventTriggerCommonSetup(Node *parsetree,
 	 *
 	 * If this cross-check fails for you, you probably need to either adjust
 	 * standard_ProcessUtility() not to invoke event triggers for the command
-	 * type in question, or you need to adjust check_ddl_tag to accept the
+	 * type in question, or you need to adjust event_trigger_ok to accept the
 	 * relevant command tag.
 	 */
 #ifdef USE_ASSERT_CHECKING
 	{
-		const char *dbgtag;
+		CommandTag	dbgtag;
 
 		dbgtag = CreateCommandTag(parsetree);
 		if (event == EVT_DDLCommandStart ||
 			event == EVT_DDLCommandEnd ||
 			event == EVT_SQLDrop)
 		{
-			if (check_ddl_tag(dbgtag) != EVENT_TRIGGER_COMMAND_TAG_OK)
-				elog(ERROR, "unexpected command tag \"%s\"", dbgtag);
+			if (!command_tag_event_trigger_ok(dbgtag))
+				elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(dbgtag));
 		}
 		else if (event == EVT_TableRewrite)
 		{
-			if (check_table_rewrite_ddl_tag(dbgtag) != EVENT_TRIGGER_COMMAND_TAG_OK)
-				elog(ERROR, "unexpected command tag \"%s\"", dbgtag);
+			if (!command_tag_table_rewrite_ok(dbgtag))
+				elog(ERROR, "unexpected command tag \"%s\"", GetCommandTagName(dbgtag));
 		}
 	}
 #endif
@@ -758,7 +642,7 @@ EventTriggerCommonSetup(Node *parsetree,
 	{
 		EventTriggerCacheItem *item = lfirst(lc);
 
-		if (filter_event_trigger(&tag, item))
+		if (filter_event_trigger(tag, item))
 		{
 			/* We must plan to fire this trigger. */
 			runlist = lappend_oid(runlist, item->fnoid);
@@ -2136,7 +2020,7 @@ pg_event_trigger_ddl_commands(PG_FUNCTION_ARGS)
 					/* objsubid */
 					values[i++] = Int32GetDatum(addr.objectSubId);
 					/* command tag */
-					values[i++] = CStringGetTextDatum(CreateCommandTag(cmd->parsetree));
+					values[i++] = CStringGetTextDatum(CreateCommandName(cmd->parsetree));
 					/* object_type */
 					values[i++] = CStringGetTextDatum(type);
 					/* schema */
@@ -2161,7 +2045,7 @@ pg_event_trigger_ddl_commands(PG_FUNCTION_ARGS)
 				/* objsubid */
 				nulls[i++] = true;
 				/* command tag */
-				values[i++] = CStringGetTextDatum(CreateCommandTag(cmd->parsetree));
+				values[i++] = CStringGetTextDatum(CreateCommandName(cmd->parsetree));
 				/* object_type */
 				values[i++] = CStringGetTextDatum(stringify_adefprivs_objtype(cmd->d.defprivs.objtype));
 				/* schema */

src/backend/commands/matview.c

@@ -136,7 +136,7 @@ SetMatViewPopulatedState(Relation relation, bool newstate)
  */
 ObjectAddress
 ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
-				   ParamListInfo params, char *completionTag)
+				   ParamListInfo params, QueryCompletion *qc)
 {
 	Oid			matviewOid;
 	Relation	matviewRel;

src/backend/commands/portalcmds.c

@@ -106,7 +106,7 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, ParamListInfo pa
 	PortalDefineQuery(portal,
 					  NULL,
 					  queryString,
-					  "SELECT", /* cursor's query is always a SELECT */
+					  CMDTAG_SELECT,	/* cursor's query is always a SELECT */
 					  list_make1(plan),
 					  NULL);
 
@@ -160,15 +160,14 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, ParamListInfo pa
  *
  *	stmt: parsetree node for command
  *	dest: where to send results
- *	completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
- *		in which to store a command completion status string.
+ *	qc: where to store a command completion status data.
  *
- * completionTag may be NULL if caller doesn't want a status string.
+ * qc may be NULL if caller doesn't want status data.
  */
 void
 PerformPortalFetch(FetchStmt *stmt,
 				   DestReceiver *dest,
-				   char *completionTag)
+				   QueryCompletion *qc)
 {
 	Portal		portal;
 	uint64		nprocessed;
@@ -203,9 +202,8 @@ PerformPortalFetch(FetchStmt *stmt,
 								dest);
 
 	/* Return command status if wanted */
-	if (completionTag)
-		snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s " UINT64_FORMAT,
-				 stmt->ismove ? "MOVE" : "FETCH",
+	if (qc)
+		SetQueryCompletion(qc, stmt->ismove ? CMDTAG_MOVE : CMDTAG_FETCH,
 						   nprocessed);
 }
 

src/backend/commands/prepare.c

@@ -187,7 +187,7 @@ void
 ExecuteQuery(ParseState *pstate,
 			 ExecuteStmt *stmt, IntoClause *intoClause,
 			 ParamListInfo params,
-			 DestReceiver *dest, char *completionTag)
+			 DestReceiver *dest, QueryCompletion *qc)
 {
 	PreparedStatement *entry;
 	CachedPlan *cplan;
@@ -288,7 +288,7 @@ ExecuteQuery(ParseState *pstate,
 	 */
 	PortalStart(portal, paramLI, eflags, GetActiveSnapshot());
 
-	(void) PortalRun(portal, count, false, true, dest, dest, completionTag);
+	(void) PortalRun(portal, count, false, true, dest, dest, qc);
 
 	PortalDrop(portal, false);
 

src/backend/executor/execMain.c

@@ -787,11 +787,11 @@ ExecCheckXactReadOnly(PlannedStmt *plannedstmt)
 		if (isTempNamespace(get_rel_namespace(rte->relid)))
 			continue;
 
-		PreventCommandIfReadOnly(CreateCommandTag((Node *) plannedstmt));
+		PreventCommandIfReadOnly(CreateCommandName((Node *) plannedstmt));
 	}
 
 	if (plannedstmt->commandType != CMD_SELECT || plannedstmt->hasModifyingCTE)
-		PreventCommandIfParallelMode(CreateCommandTag((Node *) plannedstmt));
+		PreventCommandIfParallelMode(CreateCommandName((Node *) plannedstmt));
 }
 
 

src/backend/executor/functions.c

@@ -530,7 +530,7 @@ init_execution_state(List *queryTree_list,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					/* translator: %s is a SQL statement name */
 							 errmsg("%s is not allowed in a SQL function",
-									CreateCommandTag(stmt->utilityStmt))));
+									CreateCommandName(stmt->utilityStmt))));
 			}
 
 			if (fcache->readonly_func && !CommandIsReadOnly(stmt))
@@ -538,7 +538,7 @@ init_execution_state(List *queryTree_list,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				/* translator: %s is a SQL statement name */
 						 errmsg("%s is not allowed in a non-volatile function",
-								CreateCommandTag((Node *) stmt))));
+								CreateCommandName((Node *) stmt))));
 
 			/* OK, build the execution_state for this query */
 			newes = (execution_state *) palloc(sizeof(execution_state));

src/backend/executor/spi.c

@@ -1338,7 +1338,7 @@ SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
 				(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
 		/* translator: %s is name of a SQL command, eg INSERT */
 				 errmsg("cannot open %s query as cursor",
-						plansource->commandTag)));
+						GetCommandTagName(plansource->commandTag))));
 	}
 
 	Assert(list_length(plan->plancache_list) == 1);
@@ -1469,7 +1469,7 @@ SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				/* translator: %s is a SQL statement name */
 						 errmsg("%s is not allowed in a non-volatile function",
-								CreateCommandTag((Node *) pstmt))));
+								CreateCommandName((Node *) pstmt))));
 		}
 	}
 
@@ -2255,7 +2255,7 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				/* translator: %s is a SQL statement name */
 						 errmsg("%s is not allowed in a non-volatile function",
-								CreateCommandTag((Node *) stmt))));
+								CreateCommandName((Node *) stmt))));
 
 			/*
 			 * If not read-only mode, advance the command counter before each
@@ -2291,8 +2291,8 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 			}
 			else
 			{
-				char		completionTag[COMPLETION_TAG_BUFSIZE];
 				ProcessUtilityContext context;
+				QueryCompletion qc;
 
 				/*
 				 * If the SPI context is atomic, or we are asked to manage
@@ -2306,13 +2306,14 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 				else
 					context = PROCESS_UTILITY_QUERY_NONATOMIC;
 
+				InitializeQueryCompletion(&qc);
 				ProcessUtility(stmt,
 							   plansource->query_string,
 							   context,
 							   paramLI,
 							   _SPI_current->queryEnv,
 							   dest,
-							   completionTag);
+							   &qc);
 
 				/* Update "processed" if stmt returned tuples */
 				if (_SPI_current->tuptable)
@@ -2328,9 +2329,8 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 				{
 					CreateTableAsStmt *ctastmt = (CreateTableAsStmt *) stmt->utilityStmt;
 
-					if (strncmp(completionTag, "SELECT ", 7) == 0)
-						_SPI_current->processed =
-							pg_strtouint64(completionTag + 7, NULL, 10);
+					if (qc.commandTag == CMDTAG_SELECT)
+						_SPI_current->processed = qc.nprocessed;
 					else
 					{
 						/*
@@ -2351,9 +2351,8 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 				}
 				else if (IsA(stmt->utilityStmt, CopyStmt))
 				{
-					Assert(strncmp(completionTag, "COPY ", 5) == 0);
-					_SPI_current->processed = pg_strtouint64(completionTag + 5,
-															 NULL, 10);
+					Assert(qc.commandTag == CMDTAG_COPY);
+					_SPI_current->processed = qc.nprocessed;
 				}
 			}
 

src/backend/replication/logical/decode.c

@@ -100,7 +100,7 @@ LogicalDecodingProcessRecord(LogicalDecodingContext *ctx, XLogReaderState *recor
 	buf.record = record;
 
 	/* cast so we get a warning when new rmgrs are added */
-	switch ((RmgrIds) XLogRecGetRmid(record))
+	switch ((RmgrId) XLogRecGetRmid(record))
 	{
 			/*
 			 * Rmgrs we care about for logical decoding. Add new rmgrs in

src/backend/replication/walsender.c

@@ -1074,8 +1074,11 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
 static void
 DropReplicationSlot(DropReplicationSlotCmd *cmd)
 {
+	QueryCompletion qc;
+
 	ReplicationSlotDrop(cmd->slotname, !cmd->wait);
-	EndCommand("DROP_REPLICATION_SLOT", DestRemote);
+	SetQueryCompletion(&qc, CMDTAG_DROP_REPLICATION_SLOT, 0);
+	EndCommand(&qc, DestRemote, false);
 }
 
 /*
@@ -1086,6 +1089,7 @@ static void
 StartLogicalReplication(StartReplicationCmd *cmd)
 {
 	StringInfoData buf;
+	QueryCompletion qc;
 
 	/* make sure that our requirements are still fulfilled */
 	CheckLogicalDecodingRequirements();
@@ -1160,7 +1164,8 @@ StartLogicalReplication(StartReplicationCmd *cmd)
 	WalSndSetState(WALSNDSTATE_STARTUP);
 
 	/* Get out of COPY mode (CommandComplete). */
-	EndCommand("COPY 0", DestRemote);
+	SetQueryCompletion(&qc, CMDTAG_COPY, 0);
+	EndCommand(&qc, DestRemote, false);
 }
 
 /*
@@ -1464,6 +1469,7 @@ exec_replication_command(const char *cmd_string)
 	Node	   *cmd_node;
 	MemoryContext cmd_context;
 	MemoryContext old_context;
+	QueryCompletion qc;
 
 	/*
 	 * If WAL sender has been told that shutdown is getting close, switch its
@@ -1614,7 +1620,8 @@ exec_replication_command(const char *cmd_string)
 	MemoryContextDelete(cmd_context);
 
 	/* Send CommandComplete message */
-	EndCommand("SELECT", DestRemote);
+	SetQueryCompletion(&qc, CMDTAG_SELECT, 0);
+	EndCommand(&qc, DestRemote, true);
 
 	/* Report to pgstat that this process is now idle */
 	pgstat_report_activity(STATE_IDLE, NULL);
@@ -2867,8 +2874,11 @@ WalSndDone(WalSndSendDataCallback send_data)
 	if (WalSndCaughtUp && sentPtr == replicatedPtr &&
 		!pq_is_send_pending())
 	{
+		QueryCompletion qc;
+
 		/* Inform the standby that XLOG streaming is done */
-		EndCommand("COPY 0", DestRemote);
+		SetQueryCompletion(&qc, CMDTAG_COPY, 0);
+		EndCommand(&qc, DestRemote, false);
 		pq_flush();
 
 		proc_exit(0);

src/backend/tcop/Makefile

@@ -13,6 +13,7 @@ top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = \
+	cmdtag.o \
 	dest.o \
 	fastpath.o \
 	postgres.o \

src/backend/tcop/cmdtag.c

+/*-------------------------------------------------------------------------
+ *
+ * cmdtag.c
+ *	  Data and routines for commandtag names and enumeration.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/tcop/cmdtag.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "miscadmin.h"
+#include "tcop/cmdtag.h"
+
+
+typedef struct CommandTagBehavior
+{
+	const char *name;
+	const bool	event_trigger_ok;
+	const bool	table_rewrite_ok;
+	const bool	display_rowcount;
+} CommandTagBehavior;
+
+#define PG_CMDTAG(tag, name, evtrgok, rwrok, rowcnt) \
+	{ name, evtrgok, rwrok, rowcnt },
+
+const CommandTagBehavior tag_behavior[COMMAND_TAG_NEXTTAG] = {
+#include "tcop/cmdtaglist.h"
+};
+
+#undef PG_CMDTAG
+
+void
+InitializeQueryCompletion(QueryCompletion *qc)
+{
+	qc->commandTag = CMDTAG_UNKNOWN;
+	qc->nprocessed = 0;
+}
+
+const char *
+GetCommandTagName(CommandTag commandTag)
+{
+	return tag_behavior[commandTag].name;
+}
+
+bool
+command_tag_display_rowcount(CommandTag commandTag)
+{
+	return tag_behavior[commandTag].display_rowcount;
+}
+
+bool
+command_tag_event_trigger_ok(CommandTag commandTag)
+{
+	return tag_behavior[commandTag].event_trigger_ok;
+}
+
+bool
+command_tag_table_rewrite_ok(CommandTag commandTag)
+{
+	return tag_behavior[commandTag].table_rewrite_ok;
+}
+
+/*
+ * Search CommandTag by name
+ *
+ * Returns CommandTag, or CMDTAG_UNKNOWN if not recognized
+ */
+CommandTag
+GetCommandTagEnum(const char *commandname)
+{
+	const CommandTagBehavior *base,
+			   *last,
+			   *position;
+	int			result;
+
+	if (commandname == NULL || *commandname == '\0')
+		return CMDTAG_UNKNOWN;
+
+	base = tag_behavior;
+	last = tag_behavior + lengthof(tag_behavior) - 1;
+	while (last >= base)
+	{
+		position = base + ((last - base) >> 1);
+		result = pg_strcasecmp(commandname, position->name);
+		if (result == 0)
+			return (CommandTag) (position - tag_behavior);
+		else if (result < 0)
+			last = position - 1;
+		else
+			base = position + 1;
+	}
+	return CMDTAG_UNKNOWN;
+}

src/backend/tcop/dest.c

@@ -100,7 +100,7 @@ DestReceiver *None_Receiver = (DestReceiver *) &donothingDR;
  * ----------------
  */
 void
-BeginCommand(const char *commandTag, CommandDest dest)
+BeginCommand(CommandTag commandTag, CommandDest dest)
 {
 	/* Nothing to do at present */
 }
@@ -163,8 +163,12 @@ CreateDestReceiver(CommandDest dest)
  * ----------------
  */
 void
-EndCommand(const char *commandTag, CommandDest dest)
+EndCommand(const QueryCompletion *qc, CommandDest dest, bool force_undecorated_output)
 {
+	char		completionTag[COMPLETION_TAG_BUFSIZE];
+	CommandTag	tag;
+	const char *tagname;
+
 	switch (dest)
 	{
 		case DestRemote:
@@ -172,11 +176,27 @@ EndCommand(const char *commandTag, CommandDest dest)
 		case DestRemoteSimple:
 
 			/*
-			 * We assume the commandTag is plain ASCII and therefore requires
-			 * no encoding conversion.
+			 * We assume the tagname is plain ASCII and therefore requires no
+			 * encoding conversion.
+			 *
+			 * We no longer display LastOid, but to preserve the wire
+			 * protocol, we write InvalidOid where the LastOid used to be
+			 * written.
+			 *
+			 * All cases where LastOid was written also write nprocessed
+			 * count, so just Assert that rather than having an extra test.
 			 */
-			pq_putmessage('C', commandTag, strlen(commandTag) + 1);
-			break;
+			tag = qc->commandTag;
+			tagname = GetCommandTagName(tag);
+
+			if (command_tag_display_rowcount(tag) && !force_undecorated_output)
+				snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
+						 tag == CMDTAG_INSERT ?
+						 "%s 0 " UINT64_FORMAT : "%s " UINT64_FORMAT,
+						 tagname, qc->nprocessed);
+			else
+				snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s", tagname);
+			pq_putmessage('C', completionTag, strlen(completionTag) + 1);
 
 		case DestNone:
 		case DestDebug:

src/backend/tcop/postgres.c

@@ -1064,8 +1064,8 @@ exec_simple_query(const char *query_string)
 	{
 		RawStmt    *parsetree = lfirst_node(RawStmt, parsetree_item);
 		bool		snapshot_set = false;
-		const char *commandTag;
-		char		completionTag[COMPLETION_TAG_BUFSIZE];
+		CommandTag	commandTag;
+		QueryCompletion qc;
 		MemoryContext per_parsetree_context = NULL;
 		List	   *querytree_list,
 				   *plantree_list;
@@ -1081,7 +1081,7 @@ exec_simple_query(const char *query_string)
 		 */
 		commandTag = CreateCommandTag(parsetree->stmt);
 
-		set_ps_display(commandTag, false);
+		set_ps_display(GetCommandTagName(commandTag), false);
 
 		BeginCommand(commandTag, dest);
 
@@ -1239,7 +1239,7 @@ exec_simple_query(const char *query_string)
 						 true,
 						 receiver,
 						 receiver,
-						 completionTag);
+						 &qc);
 
 		receiver->rDestroy(receiver);
 
@@ -1290,7 +1290,7 @@ exec_simple_query(const char *query_string)
 		 * command the client sent, regardless of rewriting. (But a command
 		 * aborted by error will not send an EndCommand report at all.)
 		 */
-		EndCommand(completionTag, dest);
+		EndCommand(&qc, dest, false);
 
 		/* Now we may drop the per-parsetree context, if one was created. */
 		if (per_parsetree_context)
@@ -1352,7 +1352,6 @@ exec_parse_message(const char *query_string,	/* string to execute */
 	MemoryContext oldcontext;
 	List	   *parsetree_list;
 	RawStmt    *raw_parse_tree;
-	const char *commandTag;
 	List	   *querytree_list;
 	CachedPlanSource *psrc;
 	bool		is_named;
@@ -1438,11 +1437,6 @@ exec_parse_message(const char *query_string,	/* string to execute */
 
 		raw_parse_tree = linitial_node(RawStmt, parsetree_list);
 
-		/*
-		 * Get the command name for possible use in status display.
-		 */
-		commandTag = CreateCommandTag(raw_parse_tree->stmt);
-
 		/*
 		 * If we are in an aborted transaction, reject all commands except
 		 * COMMIT/ROLLBACK.  It is important that this test occur before we
@@ -1463,7 +1457,8 @@ exec_parse_message(const char *query_string,	/* string to execute */
 		 * Create the CachedPlanSource before we do parse analysis, since it
 		 * needs to see the unmodified raw parse tree.
 		 */
-		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag);
+		psrc = CreateCachedPlan(raw_parse_tree, query_string,
+								CreateCommandTag(raw_parse_tree->stmt));
 
 		/*
 		 * Set up a snapshot if parse analysis will need one.
@@ -1514,8 +1509,8 @@ exec_parse_message(const char *query_string,	/* string to execute */
 	{
 		/* Empty input string.  This is legal. */
 		raw_parse_tree = NULL;
-		commandTag = NULL;
-		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag);
+		psrc = CreateCachedPlan(raw_parse_tree, query_string,
+								CMDTAG_UNKNOWN);
 		querytree_list = NIL;
 	}
 
@@ -2031,7 +2026,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 	DestReceiver *receiver;
 	Portal		portal;
 	bool		completed;
-	char		completionTag[COMPLETION_TAG_BUFSIZE];
+	QueryCompletion qc;
 	const char *sourceText;
 	const char *prepStmtName;
 	ParamListInfo portalParams;
@@ -2058,7 +2053,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 	 * If the original query was a null string, just return
 	 * EmptyQueryResponse.
 	 */
-	if (portal->commandTag == NULL)
+	if (portal->commandTag == CMDTAG_UNKNOWN)
 	{
 		Assert(portal->stmts == NIL);
 		NullCommand(dest);
@@ -2104,7 +2099,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 
 	pgstat_report_activity(STATE_RUNNING, sourceText);
 
-	set_ps_display(portal->commandTag, false);
+	set_ps_display(GetCommandTagName(portal->commandTag), false);
 
 	if (save_log_statement_stats)
 		ResetUsage();
@@ -2185,7 +2180,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 						  !execute_is_fetch && max_rows == FETCH_ALL,
 						  receiver,
 						  receiver,
-						  completionTag);
+						  &qc);
 
 	receiver->rDestroy(receiver);
 
@@ -2218,7 +2213,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 		}
 
 		/* Send appropriate CommandComplete to client */
-		EndCommand(completionTag, dest);
+		EndCommand(&qc, dest, false);
 	}
 	else
 	{

src/backend/tcop/pquery.c

@@ -40,7 +40,7 @@ static void ProcessQuery(PlannedStmt *plan,
 						 ParamListInfo params,
 						 QueryEnvironment *queryEnv,
 						 DestReceiver *dest,
-						 char *completionTag);
+						 QueryCompletion *qc);
 static void FillPortalStore(Portal portal, bool isTopLevel);
 static uint64 RunFromStore(Portal portal, ScanDirection direction, uint64 count,
 						   DestReceiver *dest);
@@ -48,11 +48,11 @@ static uint64 PortalRunSelect(Portal portal, bool forward, long count,
 							  DestReceiver *dest);
 static void PortalRunUtility(Portal portal, PlannedStmt *pstmt,
 							 bool isTopLevel, bool setHoldSnapshot,
-							 DestReceiver *dest, char *completionTag);
+							 DestReceiver *dest, QueryCompletion *qc);
 static void PortalRunMulti(Portal portal,
 						   bool isTopLevel, bool setHoldSnapshot,
 						   DestReceiver *dest, DestReceiver *altdest,
-						   char *completionTag);
+						   QueryCompletion *qc);
 static uint64 DoPortalRunFetch(Portal portal,
 							   FetchDirection fdirection,
 							   long count,
@@ -125,10 +125,9 @@ FreeQueryDesc(QueryDesc *qdesc)
  *	sourceText: the source text of the query
  *	params: any parameters needed
  *	dest: where to send results
- *	completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
- *		in which to store a command completion status string.
+ *	qc: where to store the command completion status data.
  *
- * completionTag may be NULL if caller doesn't want a status string.
+ * qc may be NULL if caller doesn't want a status string.
  *
  * Must be called in a memory context that will be reset or deleted on
  * error; otherwise the executor's memory usage will be leaked.
@@ -139,7 +138,7 @@ ProcessQuery(PlannedStmt *plan,
 			 ParamListInfo params,
 			 QueryEnvironment *queryEnv,
 			 DestReceiver *dest,
-			 char *completionTag)
+			 QueryCompletion *qc)
 {
 	QueryDesc  *queryDesc;
 
@@ -161,38 +160,26 @@ ProcessQuery(PlannedStmt *plan,
 	ExecutorRun(queryDesc, ForwardScanDirection, 0L, true);
 
 	/*
-	 * Build command completion status string, if caller wants one.
+	 * Build command completion status data, if caller wants one.
 	 */
-	if (completionTag)
+	if (qc)
 	{
-		Oid			lastOid;
-
 		switch (queryDesc->operation)
 		{
 			case CMD_SELECT:
-				snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-						 "SELECT " UINT64_FORMAT,
-						 queryDesc->estate->es_processed);
+				SetQueryCompletion(qc, CMDTAG_SELECT, queryDesc->estate->es_processed);
 				break;
 			case CMD_INSERT:
-				/* lastoid doesn't exist anymore */
-				lastOid = InvalidOid;
-				snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-						 "INSERT %u " UINT64_FORMAT,
-						 lastOid, queryDesc->estate->es_processed);
+				SetQueryCompletion(qc, CMDTAG_INSERT, queryDesc->estate->es_processed);
 				break;
 			case CMD_UPDATE:
-				snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-						 "UPDATE " UINT64_FORMAT,
-						 queryDesc->estate->es_processed);
+				SetQueryCompletion(qc, CMDTAG_UPDATE, queryDesc->estate->es_processed);
 				break;
 			case CMD_DELETE:
-				snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-						 "DELETE " UINT64_FORMAT,
-						 queryDesc->estate->es_processed);
+				SetQueryCompletion(qc, CMDTAG_DELETE, queryDesc->estate->es_processed);
 				break;
 			default:
-				strcpy(completionTag, "???");
+				SetQueryCompletion(qc, CMDTAG_UNKNOWN, queryDesc->estate->es_processed);
 				break;
 		}
 	}
@@ -675,9 +662,8 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
  *
  * altdest: where to send output of non-primary queries
  *
- * completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
- *		in which to store a command completion status string.
- *		May be NULL if caller doesn't want a status string.
+ * qc: where to store command completion status data.
+ *		May be NULL if caller doesn't want status data.
  *
  * Returns true if the portal's execution is complete, false if it was
  * suspended due to exhaustion of the count parameter.
@@ -685,7 +671,7 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
 bool
 PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
 		  DestReceiver *dest, DestReceiver *altdest,
-		  char *completionTag)
+		  QueryCompletion *qc)
 {
 	bool		result;
 	uint64		nprocessed;
@@ -700,9 +686,9 @@ PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
 
 	TRACE_POSTGRESQL_QUERY_EXECUTE_START();
 
-	/* Initialize completion tag to empty string */
-	if (completionTag)
-		completionTag[0] = '\0';
+	/* Initialize empty completion data */
+	if (qc)
+		InitializeQueryCompletion(qc);
 
 	if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
 	{
@@ -771,16 +757,13 @@ PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
 
 				/*
 				 * If the portal result contains a command tag and the caller
-				 * gave us a pointer to store it, copy it. Patch the "SELECT"
-				 * tag to also provide the rowcount.
+				 * gave us a pointer to store it, copy it and update the
+				 * rowcount.
 				 */
-				if (completionTag && portal->commandTag)
+				if (qc && portal->qc.commandTag != CMDTAG_UNKNOWN)
 				{
-					if (strcmp(portal->commandTag, "SELECT") == 0)
-						snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
-								 "SELECT " UINT64_FORMAT, nprocessed);
-					else
-						strcpy(completionTag, portal->commandTag);
+					CopyQueryCompletion(qc, &portal->qc);
+					qc->nprocessed = nprocessed;
 				}
 
 				/* Mark portal not active */
@@ -794,7 +777,7 @@ PortalRun(Portal portal, long count, bool isTopLevel, bool run_once,
 
 			case PORTAL_MULTI_QUERY:
 				PortalRunMulti(portal, isTopLevel, false,
-							   dest, altdest, completionTag);
+							   dest, altdest, qc);
 
 				/* Prevent portal's commands from being re-executed */
 				MarkPortalDone(portal);
@@ -1005,8 +988,9 @@ static void
 FillPortalStore(Portal portal, bool isTopLevel)
 {
 	DestReceiver *treceiver;
-	char		completionTag[COMPLETION_TAG_BUFSIZE];
+	QueryCompletion qc;
 
+	InitializeQueryCompletion(&qc);
 	PortalCreateHoldStore(portal);
 	treceiver = CreateDestReceiver(DestTuplestore);
 	SetTuplestoreDestReceiverParams(treceiver,
@@ -1014,8 +998,6 @@ FillPortalStore(Portal portal, bool isTopLevel)
 									portal->holdContext,
 									false);
 
-	completionTag[0] = '\0';
-
 	switch (portal->strategy)
 	{
 		case PORTAL_ONE_RETURNING:
@@ -1028,12 +1010,12 @@ FillPortalStore(Portal portal, bool isTopLevel)
 			 * portal's holdSnapshot to the snapshot used (or a copy of it).
 			 */
 			PortalRunMulti(portal, isTopLevel, true,
-						   treceiver, None_Receiver, completionTag);
+						   treceiver, None_Receiver, &qc);
 			break;
 
 		case PORTAL_UTIL_SELECT:
 			PortalRunUtility(portal, linitial_node(PlannedStmt, portal->stmts),
-							 isTopLevel, true, treceiver, completionTag);
+							 isTopLevel, true, treceiver, &qc);
 			break;
 
 		default:
@@ -1042,9 +1024,9 @@ FillPortalStore(Portal portal, bool isTopLevel)
 			break;
 	}
 
-	/* Override default completion tag with actual command result */
-	if (completionTag[0] != '\0')
-		portal->commandTag = pstrdup(completionTag);
+	/* Override portal completion data with actual command results */
+	if (qc.commandTag != CMDTAG_UNKNOWN)
+		CopyQueryCompletion(&portal->qc, &qc);
 
 	treceiver->rDestroy(treceiver);
 }
@@ -1130,7 +1112,7 @@ RunFromStore(Portal portal, ScanDirection direction, uint64 count,
 static void
 PortalRunUtility(Portal portal, PlannedStmt *pstmt,
 				 bool isTopLevel, bool setHoldSnapshot,
-				 DestReceiver *dest, char *completionTag)
+				 DestReceiver *dest, QueryCompletion *qc)
 {
 	Node	   *utilityStmt = pstmt->utilityStmt;
 	Snapshot	snapshot;
@@ -1178,7 +1160,7 @@ PortalRunUtility(Portal portal, PlannedStmt *pstmt,
 				   portal->portalParams,
 				   portal->queryEnv,
 				   dest,
-				   completionTag);
+				   qc);
 
 	/* Some utility statements may change context on us */
 	MemoryContextSwitchTo(portal->portalContext);
@@ -1202,7 +1184,7 @@ static void
 PortalRunMulti(Portal portal,
 			   bool isTopLevel, bool setHoldSnapshot,
 			   DestReceiver *dest, DestReceiver *altdest,
-			   char *completionTag)
+			   QueryCompletion *qc)
 {
 	bool		active_snapshot_set = false;
 	ListCell   *stmtlist_item;
@@ -1284,7 +1266,7 @@ PortalRunMulti(Portal portal,
 							 portal->sourceText,
 							 portal->portalParams,
 							 portal->queryEnv,
-							 dest, completionTag);
+							 dest, qc);
 			}
 			else
 			{
@@ -1319,7 +1301,7 @@ PortalRunMulti(Portal portal,
 				Assert(!active_snapshot_set);
 				/* statement can set tag string */
 				PortalRunUtility(portal, pstmt, isTopLevel, false,
-								 dest, completionTag);
+								 dest, qc);
 			}
 			else
 			{
@@ -1350,8 +1332,8 @@ PortalRunMulti(Portal portal,
 		PopActiveSnapshot();
 
 	/*
-	 * If a command completion tag was supplied, use it.  Otherwise use the
-	 * portal's commandTag as the default completion tag.
+	 * If a query completion data was supplied, use it.  Otherwise use the
+	 * portal's query completion data.
 	 *
 	 * Exception: Clients expect INSERT/UPDATE/DELETE tags to have counts, so
 	 * fake them with zeros.  This can happen with DO INSTEAD rules if there
@@ -1361,18 +1343,12 @@ PortalRunMulti(Portal portal,
 	 * e.g.  an INSERT that does an UPDATE instead should not print "0 1" if
 	 * one row was updated.  See QueryRewrite(), step 3, for details.
 	 */
-	if (completionTag && completionTag[0] == '\0')
-	{
-		if (portal->commandTag)
-			strcpy(completionTag, portal->commandTag);
-		if (strcmp(completionTag, "SELECT") == 0)
-			sprintf(completionTag, "SELECT 0 0");
-		else if (strcmp(completionTag, "INSERT") == 0)
-			strcpy(completionTag, "INSERT 0 0");
-		else if (strcmp(completionTag, "UPDATE") == 0)
-			strcpy(completionTag, "UPDATE 0");
-		else if (strcmp(completionTag, "DELETE") == 0)
-			strcpy(completionTag, "DELETE 0");
+	if (qc && qc->commandTag == CMDTAG_UNKNOWN)
+	{
+		if (portal->qc.commandTag != CMDTAG_UNKNOWN)
+			CopyQueryCompletion(qc, &portal->qc);
+		/* If the caller supplied a qc, we should have set it by now. */
+		Assert(qc->commandTag != CMDTAG_UNKNOWN);
 	}
 }
 

src/backend/utils/cache/evtcache.c

@@ -20,6 +20,7 @@
 #include "catalog/pg_event_trigger.h"
 #include "catalog/pg_type.h"
 #include "commands/trigger.h"
+#include "tcop/cmdtag.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
 #include "utils/catcache.h"
@@ -51,7 +52,7 @@ static EventTriggerCacheStateType EventTriggerCacheState = ETCS_NEEDS_REBUILD;
 static void BuildEventTriggerCache(void);
 static void InvalidateEventCacheCallback(Datum arg,
 										 int cacheid, uint32 hashvalue);
-static int	DecodeTextArrayToCString(Datum array, char ***cstringp);
+static Bitmapset *DecodeTextArrayToBitmapset(Datum array);
 
 /*
  * Search the event cache by trigger event.
@@ -180,10 +181,7 @@ BuildEventTriggerCache(void)
 		evttags = heap_getattr(tup, Anum_pg_event_trigger_evttags,
 							   RelationGetDescr(rel), &evttags_isnull);
 		if (!evttags_isnull)
-		{
-			item->ntags = DecodeTextArrayToCString(evttags, &item->tag);
-			qsort(item->tag, item->ntags, sizeof(char *), pg_qsort_strcmp);
-		}
+			item->tagset = DecodeTextArrayToBitmapset(evttags);
 
 		/* Add to cache entry. */
 		entry = hash_search(cache, &event, HASH_ENTER, &found);
@@ -215,18 +213,18 @@ BuildEventTriggerCache(void)
 }
 
 /*
- * Decode text[] to an array of C strings.
+ * Decode text[] to a Bitmapset of CommandTags.
  *
  * We could avoid a bit of overhead here if we were willing to duplicate some
  * of the logic from deconstruct_array, but it doesn't seem worth the code
  * complexity.
  */
-static int
-DecodeTextArrayToCString(Datum array, char ***cstringp)
+static Bitmapset *
+DecodeTextArrayToBitmapset(Datum array)
 {
 	ArrayType  *arr = DatumGetArrayTypeP(array);
 	Datum	   *elems;
-	char	  **cstring;
+	Bitmapset  *bms;
 	int			i;
 	int			nelems;
 
@@ -234,13 +232,17 @@ DecodeTextArrayToCString(Datum array, char ***cstringp)
 		elog(ERROR, "expected 1-D text array");
 	deconstruct_array(arr, TEXTOID, -1, false, 'i', &elems, NULL, &nelems);
 
-	cstring = palloc(nelems * sizeof(char *));
-	for (i = 0; i < nelems; ++i)
-		cstring[i] = TextDatumGetCString(elems[i]);
+	for (bms = NULL, i = 0; i < nelems; ++i)
+	{
+		char	   *str = TextDatumGetCString(elems[i]);
+
+		bms = bms_add_member(bms, GetCommandTagEnum(str));
+		pfree(str);
+	}
 
 	pfree(elems);
-	*cstringp = cstring;
-	return nelems;
+
+	return bms;
 }
 
 /*

src/backend/utils/cache/plancache.c

@@ -158,12 +158,12 @@ InitPlanCache(void)
  *
  * raw_parse_tree: output of raw_parser(), or NULL if empty query
  * query_string: original query text
- * commandTag: compile-time-constant tag for query, or NULL if empty query
+ * commandTag: command tag for query, or UNKNOWN if empty query
  */
 CachedPlanSource *
 CreateCachedPlan(RawStmt *raw_parse_tree,
 				 const char *query_string,
-				 const char *commandTag)
+				 CommandTag commandTag)
 {
 	CachedPlanSource *plansource;
 	MemoryContext source_context;
@@ -241,12 +241,12 @@ CreateCachedPlan(RawStmt *raw_parse_tree,
  *
  * raw_parse_tree: output of raw_parser(), or NULL if empty query
  * query_string: original query text
- * commandTag: compile-time-constant tag for query, or NULL if empty query
+ * commandTag: command tag for query, or NULL if empty query
  */
 CachedPlanSource *
 CreateOneShotCachedPlan(RawStmt *raw_parse_tree,
 						const char *query_string,
-						const char *commandTag)
+						CommandTag commandTag)
 {
 	CachedPlanSource *plansource;
 

src/backend/utils/mmgr/portalmem.c

@@ -281,7 +281,7 @@ void
 PortalDefineQuery(Portal portal,
 				  const char *prepStmtName,
 				  const char *sourceText,
-				  const char *commandTag,
+				  CommandTag commandTag,
 				  List *stmts,
 				  CachedPlan *cplan)
 {
@@ -289,10 +289,12 @@ PortalDefineQuery(Portal portal,
 	AssertState(portal->status == PORTAL_NEW);
 
 	AssertArg(sourceText != NULL);
-	AssertArg(commandTag != NULL || stmts == NIL);
+	AssertArg(commandTag != CMDTAG_UNKNOWN || stmts == NIL);
 
 	portal->prepStmtName = prepStmtName;
 	portal->sourceText = sourceText;
+	portal->qc.commandTag = commandTag;
+	portal->qc.nprocessed = 0;
 	portal->commandTag = commandTag;
 	portal->stmts = stmts;
 	portal->cplan = cplan;

src/include/commands/createas.h

@@ -22,7 +22,8 @@
 
 
 extern ObjectAddress ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
-									   ParamListInfo params, QueryEnvironment *queryEnv, char *completionTag);
+									   ParamListInfo params, QueryEnvironment *queryEnv,
+									   QueryCompletion *qc);
 
 extern int	GetIntoRelEFlags(IntoClause *intoClause);
 

src/include/commands/event_trigger.h

@@ -17,6 +17,7 @@
 #include "catalog/objectaddress.h"
 #include "catalog/pg_event_trigger.h"
 #include "nodes/parsenodes.h"
+#include "tcop/cmdtag.h"
 #include "tcop/deparse_utility.h"
 #include "utils/aclchk_internal.h"
 
@@ -25,7 +26,7 @@ typedef struct EventTriggerData
 	NodeTag		type;
 	const char *event;			/* event name */
 	Node	   *parsetree;		/* parse tree */
-	const char *tag;			/* command tag */
+	CommandTag	tag;
 } EventTriggerData;
 
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01

src/include/commands/matview.h

@@ -24,7 +24,7 @@
 extern void SetMatViewPopulatedState(Relation relation, bool newstate);
 
 extern ObjectAddress ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
-										ParamListInfo params, char *completionTag);
+										ParamListInfo params, QueryCompletion *qc);
 
 extern DestReceiver *CreateTransientRelDestReceiver(Oid oid);
 

src/include/commands/portalcmds.h

@@ -23,7 +23,7 @@ extern void PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, Para
 							  bool isTopLevel);
 
 extern void PerformPortalFetch(FetchStmt *stmt, DestReceiver *dest,
-							   char *completionTag);
+							   QueryCompletion *qc);
 
 extern void PerformPortalClose(const char *name);
 

src/include/commands/prepare.h

@@ -40,7 +40,7 @@ extern void PrepareQuery(ParseState *pstate, PrepareStmt *stmt,
 extern void ExecuteQuery(ParseState *pstate,
 						 ExecuteStmt *stmt, IntoClause *intoClause,
 						 ParamListInfo params,
-						 DestReceiver *dest, char *completionTag);
+						 DestReceiver *dest, QueryCompletion *qc);
 extern void DeallocateQuery(DeallocateStmt *stmt);
 extern void ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into,
 								ExplainState *es, const char *queryString,

src/include/tcop/cmdtag.h

+/*-------------------------------------------------------------------------
+ *
+ * cmdtag.h
+ *	  Declarations for commandtag names and enumeration.
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/tcop/cmdtag.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef CMDTAG_H
+#define CMDTAG_H
+
+
+#define PG_CMDTAG(tag, name, evtrgok, rwrok, rowcnt) \
+	tag,
+
+typedef enum CommandTag
+{
+#include "tcop/cmdtaglist.h"
+	COMMAND_TAG_NEXTTAG
+} CommandTag;
+
+#undef PG_CMDTAG
+
+typedef struct QueryCompletion
+{
+	CommandTag	commandTag;
+	uint64		nprocessed;
+} QueryCompletion;
+
+
+static inline void
+SetQueryCompletion(QueryCompletion *qc, CommandTag commandTag,
+				   uint64 nprocessed)
+{
+	qc->commandTag = commandTag;
+	qc->nprocessed = nprocessed;
+}
+
+static inline void
+CopyQueryCompletion(QueryCompletion *dst, const QueryCompletion *src)
+{
+	dst->commandTag = src->commandTag;
+	dst->nprocessed = src->nprocessed;
+}
+
+
+extern void InitializeQueryCompletion(QueryCompletion *qc);
+extern const char *GetCommandTagName(CommandTag commandTag);
+extern bool command_tag_display_rowcount(CommandTag commandTag);
+extern bool command_tag_event_trigger_ok(CommandTag commandTag);
+extern bool command_tag_table_rewrite_ok(CommandTag commandTag);
+extern CommandTag GetCommandTagEnum(const char *tagname);
+
+#endif							/* CMDTAG_H */

src/include/tcop/dest.h

@@ -68,6 +68,7 @@
 #define DEST_H
 
 #include "executor/tuptable.h"
+#include "tcop/cmdtag.h"
 
 
 /* buffer size to use for command completion tags */
@@ -134,9 +135,10 @@ extern PGDLLIMPORT DestReceiver *None_Receiver; /* permanent receiver for
 
 /* The primary destination management functions */
 
-extern void BeginCommand(const char *commandTag, CommandDest dest);
+extern void BeginCommand(CommandTag commandTag, CommandDest dest);
 extern DestReceiver *CreateDestReceiver(CommandDest dest);
-extern void EndCommand(const char *commandTag, CommandDest dest);
+extern void EndCommand(const QueryCompletion *qc, CommandDest dest,
+					   bool force_undecorated_output);
 
 /* Additional functions that go with destination management, more or less. */
 

src/include/tcop/pquery.h

@@ -35,7 +35,7 @@ extern void PortalSetResultFormat(Portal portal, int nFormats,
 
 extern bool PortalRun(Portal portal, long count, bool isTopLevel,
 					  bool run_once, DestReceiver *dest, DestReceiver *altdest,
-					  char *completionTag);
+					  QueryCompletion *qc);
 
 extern uint64 PortalRunFetch(Portal portal,
 							 FetchDirection fdirection,

src/include/tcop/utility.h

@@ -14,6 +14,7 @@
 #ifndef UTILITY_H
 #define UTILITY_H
 
+#include "tcop/cmdtag.h"
 #include "tcop/tcopprot.h"
 
 typedef enum
@@ -71,17 +72,17 @@ typedef void (*ProcessUtility_hook_type) (PlannedStmt *pstmt,
 										  const char *queryString, ProcessUtilityContext context,
 										  ParamListInfo params,
 										  QueryEnvironment *queryEnv,
-										  DestReceiver *dest, char *completionTag);
+										  DestReceiver *dest, QueryCompletion *qc);
 extern PGDLLIMPORT ProcessUtility_hook_type ProcessUtility_hook;
 
 extern void ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 						   ProcessUtilityContext context, ParamListInfo params,
 						   QueryEnvironment *queryEnv,
-						   DestReceiver *dest, char *completionTag);
+						   DestReceiver *dest, QueryCompletion *qc);
 extern void standard_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 									ProcessUtilityContext context, ParamListInfo params,
 									QueryEnvironment *queryEnv,
-									DestReceiver *dest, char *completionTag);
+									DestReceiver *dest, QueryCompletion *qc);
 
 extern void ProcessUtilityForAlterTable(Node *stmt,
 										AlterTableUtilityContext *context);
@@ -92,7 +93,13 @@ extern TupleDesc UtilityTupleDescriptor(Node *parsetree);
 
 extern Query *UtilityContainsQuery(Node *parsetree);
 
-extern const char *CreateCommandTag(Node *parsetree);
+extern CommandTag CreateCommandTag(Node *parsetree);
+
+static inline const char *
+CreateCommandName(Node *parsetree)
+{
+	return GetCommandTagName(CreateCommandTag(parsetree));
+}
 
 extern LogStmtLevel GetCommandLogLevel(Node *parsetree);
 

src/include/utils/evtcache.h

@@ -28,8 +28,7 @@ typedef struct
 {
 	Oid			fnoid;			/* function to be called */
 	char		enabled;		/* as SESSION_REPLICATION_ROLE_* */
-	int			ntags;			/* number of command tags */
-	char	  **tag;			/* command tags in SORTED order */
+	Bitmapset  *tagset;			/* command tags, or NULL if empty */
 } EventTriggerCacheItem;
 
 extern List *EventCacheLookup(EventTriggerEvent event);

src/include/utils/plancache.h

@@ -18,6 +18,7 @@
 #include "access/tupdesc.h"
 #include "lib/ilist.h"
 #include "nodes/params.h"
+#include "tcop/cmdtag.h"
 #include "utils/queryenvironment.h"
 
 /* Forward declaration, to avoid including parsenodes.h here */
@@ -95,7 +96,7 @@ typedef struct CachedPlanSource
 	int			magic;			/* should equal CACHEDPLANSOURCE_MAGIC */
 	struct RawStmt *raw_parse_tree; /* output of raw_parser(), or NULL */
 	const char *query_string;	/* source text of query */
-	const char *commandTag;		/* command tag (a constant!), or NULL */
+	CommandTag	commandTag;		/* 'nuff said */
 	Oid		   *param_types;	/* array of parameter type OIDs, or NULL */
 	int			num_params;		/* length of param_types array */
 	ParserSetupHook parserSetup;	/* alternative parameter spec method */
@@ -186,10 +187,10 @@ extern void ResetPlanCache(void);
 
 extern CachedPlanSource *CreateCachedPlan(struct RawStmt *raw_parse_tree,
 										  const char *query_string,
-										  const char *commandTag);
+										  CommandTag commandTag);
 extern CachedPlanSource *CreateOneShotCachedPlan(struct RawStmt *raw_parse_tree,
 												 const char *query_string,
-												 const char *commandTag);
+												 CommandTag commandTag);
 extern void CompleteCachedPlan(CachedPlanSource *plansource,
 							   List *querytree_list,
 							   MemoryContext querytree_context,

src/include/utils/portal.h

@@ -48,6 +48,7 @@
 
 #include "datatype/timestamp.h"
 #include "executor/execdesc.h"
+#include "tcop/cmdtag.h"
 #include "utils/plancache.h"
 #include "utils/resowner.h"
 
@@ -132,7 +133,8 @@ typedef struct PortalData
 
 	/* The query or queries the portal will execute */
 	const char *sourceText;		/* text of query (as of 8.4, never NULL) */
-	const char *commandTag;		/* command tag for original query */
+	CommandTag	commandTag;		/* command tag for original query */
+	QueryCompletion qc;			/* command completion data for executed query */
 	List	   *stmts;			/* list of PlannedStmts */
 	CachedPlan *cplan;			/* CachedPlan, if stmts are from one */
 
@@ -227,7 +229,7 @@ extern Portal GetPortalByName(const char *name);
 extern void PortalDefineQuery(Portal portal,
 							  const char *prepStmtName,
 							  const char *sourceText,
-							  const char *commandTag,
+							  CommandTag commandTag,
 							  List *stmts,
 							  CachedPlan *cplan);
 extern PlannedStmt *PortalGetPrimaryStmt(Portal portal);

src/pl/plperl/plperl.c

@@ -1737,7 +1737,7 @@ plperl_event_trigger_build_args(FunctionCallInfo fcinfo)
 	tdata = (EventTriggerData *) fcinfo->context;
 
 	hv_store_string(hv, "event", cstr2sv(tdata->event));
-	hv_store_string(hv, "tag", cstr2sv(tdata->tag));
+	hv_store_string(hv, "tag", cstr2sv(GetCommandTagName(tdata->tag)));
 
 	return newRV_noinc((SV *) hv);
 }

src/pl/plpgsql/src/pl_exec.c

@@ -37,6 +37,7 @@
 #include "parser/scansup.h"
 #include "plpgsql.h"
 #include "storage/proc.h"
+#include "tcop/cmdtag.h"
 #include "tcop/tcopprot.h"
 #include "tcop/utility.h"
 #include "utils/array.h"
@@ -1473,7 +1474,7 @@ plpgsql_fulfill_promise(PLpgSQL_execstate *estate,
 		case PLPGSQL_PROMISE_TG_TAG:
 			if (estate->evtrigdata == NULL)
 				elog(ERROR, "event trigger promise is not in an event trigger function");
-			assign_text_var(estate, var, estate->evtrigdata->tag);
+			assign_text_var(estate, var, GetCommandTagName(estate->evtrigdata->tag));
 			break;
 
 		default:
@@ -4115,10 +4116,9 @@ exec_stmt_execsql(PLpgSQL_execstate *estate,
 			 * tree(s), since those are the result of rewriting and could have
 			 * been transmogrified into something else entirely.
 			 */
-			if (plansource->commandTag &&
-				(strcmp(plansource->commandTag, "INSERT") == 0 ||
-				 strcmp(plansource->commandTag, "UPDATE") == 0 ||
-				 strcmp(plansource->commandTag, "DELETE") == 0))
+			if (plansource->commandTag == CMDTAG_INSERT ||
+				plansource->commandTag == CMDTAG_UPDATE ||
+				plansource->commandTag == CMDTAG_DELETE)
 			{
 				stmt->mod_stmt = true;
 				break;

src/pl/tcl/pltcl.c

@@ -1329,7 +1329,8 @@ pltcl_event_trigger_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
 	Tcl_ListObjAppendElement(NULL, tcl_cmd,
 							 Tcl_NewStringObj(utf_e2u(tdata->event), -1));
 	Tcl_ListObjAppendElement(NULL, tcl_cmd,
-							 Tcl_NewStringObj(utf_e2u(tdata->tag), -1));
+							 Tcl_NewStringObj(utf_e2u(GetCommandTagName(tdata->tag)),
+											  -1));
 
 	tcl_rc = Tcl_EvalObjEx(interp, tcl_cmd, (TCL_EVAL_DIRECT | TCL_EVAL_GLOBAL));
 

src/test/modules/test_ddl_deparse/test_ddl_deparse.c

@@ -74,7 +74,7 @@ get_command_tag(PG_FUNCTION_ARGS)
 	if (!cmd->parsetree)
 		PG_RETURN_NULL();
 
-	PG_RETURN_TEXT_P(cstring_to_text(CreateCommandTag(cmd->parsetree)));
+	PG_RETURN_TEXT_P(cstring_to_text(CreateCommandName(cmd->parsetree)));
 }
 
 /*