[HACKERS] Proposed patch for ODBC driver w/ C-a-n-c-e-l

    From: Bradley McLean <brad@bradm.net>

Patch against 7,2 submitted for comment.

This seems to work just fine; Now, when our users submit a 2 hour
query with four million row sorts by accident, then cancel it 30 seconds
later, it doesn't bog down the server ...

src/interfaces/odbc/connection.c

@@ -19,6 +19,9 @@
 #include <stdio.h>
 #include <string.h>
 #include <ctype.h>
+#ifndef	WIN32
+#include <errno.h>
+#endif /* WIN32 */
 
 #include "environ.h"
 #include "socket.h"
@@ -289,6 +292,7 @@ CC_Constructor()
 		rv->ms_jet = 0;
 		rv->unicode = 0;
 		rv->result_uncommitted = 0;
+		rv->schema_support = 0;
 #ifdef	MULTIBYTE
 		rv->client_encoding = NULL;
 		rv->server_encoding = NULL;
@@ -882,8 +886,8 @@ another_version_retry:
 					}
 					break;
 				case 'K':		/* Secret key (6.4 protocol) */
-					(void) SOCK_get_int(sock, 4);		/* pid */
-					(void) SOCK_get_int(sock, 4);		/* key */
+					self->be_pid = SOCK_get_int(sock, 4);		/* pid */
+					self->be_key = SOCK_get_int(sock, 4);		/* key */
 
 					break;
 				case 'Z':		/* Backend is ready for new query (6.4) */
@@ -1960,6 +1964,8 @@ CC_lookup_pg_version(ConnectionClass *self)
 		self->pg_version_minor = minor;
 	}
 	self->pg_version_number = (float) atof(szVersion);
+	if (PG_VERSION_GE(self, 7.3))
+		self->schema_support = 1;
 
 	mylog("Got the PostgreSQL version string: '%s'\n", self->pg_version);
 	mylog("Extracted PostgreSQL version number: '%1.1f'\n", self->pg_version_number);
@@ -2019,3 +2025,64 @@ CC_get_max_query_len(const ConnectionClass *conn)
 		value = BLCKSZ;
 	return value;
 }
+
+int
+CC_send_cancel_request(const ConnectionClass *conn)
+{
+#ifdef WIN32
+	int			save_errno = (WSAGetLastError());
+#else
+	int			save_errno = errno;
+#endif
+	int			tmpsock = -1;
+	struct
+	{
+		uint32		packetlen;
+		CancelRequestPacket cp;
+	}			crp;
+
+	/* Check we have an open connection */
+	if (!conn)
+		return FALSE;
+
+	if (conn->sock == NULL )
+	{
+		return FALSE;
+	}
+
+	/*
+	 * We need to open a temporary connection to the postmaster. Use the
+	 * information saved by connectDB to do this with only kernel calls.
+	*/
+	if ((tmpsock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+	{
+		return FALSE;
+	}
+	if (connect(tmpsock, (struct sockaddr *)&(conn->sock->sadr),
+				sizeof(conn->sock->sadr)) < 0)
+	{
+		return FALSE;
+	}
+
+	/*
+	 * We needn't set nonblocking I/O or NODELAY options here.
+	 */
+	crp.packetlen = htonl((uint32) sizeof(crp));
+	crp.cp.cancelRequestCode = (MsgType) htonl(CANCEL_REQUEST_CODE);
+	crp.cp.backendPID = htonl(conn->be_pid);
+	crp.cp.cancelAuthCode = htonl(conn->be_key);
+
+	if (send(tmpsock, (char *) &crp, sizeof(crp), 0) != (int) sizeof(crp))
+	{
+		return FALSE;
+	}
+
+	/* Sent it, done */
+	closesocket(tmpsock);
+#ifdef WIN32
+	WSASetLastError(save_errno);
+#else
+	errno = save_errno;
+#endif
+	return TRUE;
+}

src/interfaces/odbc/connection.h

@@ -126,6 +126,21 @@ typedef struct _StartupPacket6_2
 	char		tty[PATH_SIZE];
 } StartupPacket6_2;
 
+/* Transferred from pqcomm.h:  */
+
+
+typedef ProtocolVersion MsgType;
+
+#define PG_PROTOCOL(m,n)   (((m) << 16) | (n))
+#define CANCEL_REQUEST_CODE PG_PROTOCOL(1234,5678)
+
+typedef struct CancelRequestPacket
+{
+	/* Note that each field is stored in network byte order! */
+	MsgType		cancelRequestCode;	/* code to identify a cancel request */
+	unsigned int	backendPID;	/* PID of client's backend */
+	unsigned int	cancelAuthCode; /* secret key to authorize cancel */
+} CancelRequestPacket;
 
 /*	Structure to hold all the connection attributes for a specific
 	connection (used for both registry and file, DSN and DRIVER)
@@ -273,11 +288,14 @@ struct ConnectionClass_
 	char		ms_jet;
 	char		unicode;
 	char		result_uncommitted;
+	char		schema_support;
 #ifdef	MULTIBYTE
 	char	   *client_encoding;
 	char	   *server_encoding;
 #endif   /* MULTIBYTE */
 	int	ccsc;
+	int		be_pid;	/* pid returned by backend */
+	int		be_key; /* auth code needed to send cancel */
 };
 
 
@@ -319,6 +337,7 @@ void		CC_lookup_pg_version(ConnectionClass *conn);
 void		CC_initialize_pg_version(ConnectionClass *conn);
 void		CC_log_error(const char *func, const char *desc, const ConnectionClass *self);
 int			CC_get_max_query_len(const ConnectionClass *self);
+int		CC_send_cancel_request(const ConnectionClass *conn);
 void		CC_on_commit(ConnectionClass *conn);
 void		CC_on_abort(ConnectionClass *conn, BOOL set_no_trans);
 void		ProcessRollback(ConnectionClass *conn, BOOL undo);

src/interfaces/odbc/descriptor.h

@@ -5,7 +5,7 @@
  *
  * Comments:		See "notice.txt" for copyright and license information.
  *
- * $Id: descriptor.h,v 1.2 2002/04/01 03:01:14 inoue Exp $
+ * $Id: descriptor.h,v 1.3 2002/04/02 10:50:44 inoue Exp $
  *
  */
 
@@ -17,6 +17,7 @@
 typedef struct
 {
 	COL_INFO	*col_info; /* cached SQLColumns info for this table */
+	char		schema[MAX_TABLE_LEN + 1];
 	char		name[MAX_TABLE_LEN + 1];
 	char		alias[MAX_TABLE_LEN + 1];
 } TABLE_INFO;

src/interfaces/odbc/execute.c

@@ -573,6 +573,7 @@ PGAPI_Cancel(
 {
 	static char *func = "PGAPI_Cancel";
 	StatementClass *stmt = (StatementClass *) hstmt;
+	ConnectionClass *conn;
 	RETCODE		result;
 	ConnInfo   *ci;
 
@@ -589,7 +590,8 @@ PGAPI_Cancel(
 		SC_log_error(func, "", NULL);
 		return SQL_INVALID_HANDLE;
 	}
-	ci = &(SC_get_conn(stmt)->connInfo);
+	conn = SC_get_conn(stmt);
+	ci = &(conn->connInfo);
 
 	/*
 	 * Not in the middle of SQLParamData/SQLPutData so cancel like a
@@ -597,6 +599,11 @@ PGAPI_Cancel(
 	 */
 	if (stmt->data_at_exec < 0)
 	{
+		/*
+		 * Tell the Backend that we're cancelling this request
+		 */
+		if (stmt->status == STMT_EXECUTING)
+			CC_send_cancel_request(conn);
 		/*
 		 * MAJOR HACK for Windows to reset the driver manager's cursor
 		 * state: Because of what seems like a bug in the Odbc driver

src/interfaces/odbc/info30.c

@@ -171,10 +171,10 @@ PGAPI_GetInfo30(HDBC hdbc, UWORD fInfoType, PTR rgbInfoValue,
 			break;
 		case SQL_CREATE_SCHEMA:
 			len = 4;
-			if (PG_VERSION_LE(conn, 7.2))
-				value = 0;
+			if (conn->schema_support)
+				value = SQL_CS_CREATE_SCHEMA | SQL_CS_AUTHORIZATION;
 			else
-				value = SQL_CS_CREATE_SCHEMA | SQL_CS_AUTHORIZATION; /* hopefully */
+				value = 0;
 			break;
 		case SQL_CREATE_TABLE:
 			len = 4;
@@ -218,10 +218,10 @@ PGAPI_GetInfo30(HDBC hdbc, UWORD fInfoType, PTR rgbInfoValue,
 			break;
 		case SQL_DROP_SCHEMA:
 			len = 4;
-			if (PG_VERSION_LE(conn, 7.2))
-				value = 0;
+			if (conn->schema_support)
+				value = SQL_DS_DROP_SCHEMA | SQL_DS_RESTRICT | SQL_DS_CASCADE;
 			else
-				value = SQL_DS_DROP_SCHEMA | SQL_DS_RESTRICT | SQL_DS_CASCADE; /* hopefully */
+				value = 0;
 			break;
 		case SQL_DROP_TABLE:
 			len = 4;

src/interfaces/odbc/misc.c

@@ -279,6 +279,18 @@ my_strcat(char *buf, const char *fmt, const char *s, int len)
 	return NULL;
 }
 
+char *
+schema_strcat(char *buf, const char *fmt, const char *s, int len, const char *tbname, int tbnmlen)
+{
+	if (!s || 0 == len)
+	{
+		if (tbname && (tbnmlen > 0 || tbnmlen == SQL_NTS))
+			return my_strcat(buf, fmt, "public", 6);
+		return NULL;
+	}
+	return my_strcat(buf, fmt, s, len);
+}
+
 
 void
 remove_newlines(char *string)

src/interfaces/odbc/misc.h

@@ -89,6 +89,9 @@ char	   *strncpy_null(char *dst, const char *src, int len);
 char	   *trim(char *string);
 char	   *make_string(const char *s, int len, char *buf);
 char	   *my_strcat(char *buf, const char *fmt, const char *s, int len);
+char	   *schema_strcat(char *buf, const char *fmt, const char *s, int len,
+			const char *, int);
+#define	GET_SCHEMA_NAME(nspname) 	(stricmp(nspname, "public") ? nspname : "")
 
 /* defines for return value of my_strcpy */
 #define STRCPY_SUCCESS		1

src/interfaces/odbc/parse.c

@@ -543,15 +543,21 @@ parse_statement(StatementClass *stmt)
 			 */
 			if (in_dot)
 			{
-				irdflds->nfields--;
-				strcpy(fi[irdflds->nfields]->dot, fi[irdflds->nfields]->name);
-				strcpy(fi[irdflds->nfields]->name, token);
-				irdflds->nfields++;
-				in_dot = FALSE;
+				int	ifld = irdflds->nfields - 1;
+
+				if (fi[ifld]->dot[0])
+				{
+					strcat(fi[ifld]->dot, ".");
+					strcat(fi[ifld]->dot, fi[ifld]->name);
+				}
+				else
+					strcpy(fi[ifld]->dot, fi[ifld]->name);
+				strcpy(fi[ifld]->name, token);
 
 				if (delim == ',')
 				{
 					mylog("in_dot: got comma\n");
+					in_dot = FALSE;
 					in_field = FALSE;
 				}
 				continue;
@@ -575,6 +581,7 @@ parse_statement(StatementClass *stmt)
 			/* Function */
 			if (token[0] == '(')
 			{
+				in_dot = FALSE;
 				in_func = TRUE;
 				blevel = 1;
 				fi[irdflds->nfields - 1]->func = TRUE;
@@ -594,6 +601,7 @@ parse_statement(StatementClass *stmt)
 				continue;
 			}
 
+			in_dot = FALSE;
 			if (!stricmp(token, "as"))
 			{
 				in_as = TRUE;
@@ -644,6 +652,7 @@ parse_statement(StatementClass *stmt)
 					return FALSE;
 				}
 
+				ti[stmt->ntab]->schema[0] = '\0';
 				ti[stmt->ntab]->alias[0] = '\0';
 
 				strcpy(ti[stmt->ntab]->name, token);
@@ -680,6 +689,7 @@ parse_statement(StatementClass *stmt)
 					in_table = TRUE;
 				}
 				stmt->ntab++;
+				in_dot = FALSE;
 				continue;
 			}
 
@@ -689,9 +699,21 @@ parse_statement(StatementClass *stmt)
 				out_table = TRUE;
 				continue;
 			}
-			if (in_table && stricmp(token, "as"))
+			if (in_table)
 			{
-				if (!dquote)
+				if (in_dot)
+				{
+					strcpy(ti[stmt->ntab - 1]->schema, ti[stmt->ntab - 1]->name);
+					strcpy(ti[stmt->ntab - 1]->name, token);
+					in_dot = FALSE;
+					continue;
+				}
+				if (strcmp(token, ".") == 0)
+				{
+					in_dot = TRUE;
+					continue;
+				}
+				if (!dquote && stricmp(token, "as"))
 				{
 					if (stricmp(token, "LEFT") == 0 ||
 					    stricmp(token, "RIGHT") == 0 ||
@@ -702,7 +724,6 @@ parse_statement(StatementClass *stmt)
 						in_table = FALSE;
 						continue;
 					}
-				}
 					strcpy(ti[stmt->ntab - 1]->alias, token);
 					mylog("alias for table '%s' is '%s'\n", ti[stmt->ntab - 1]->name, ti[stmt->ntab - 1]->alias);
 					in_table = FALSE;
@@ -712,6 +733,7 @@ parse_statement(StatementClass *stmt)
 						mylog("more than 1 tables\n");
 					}
 				}
+			}
 		} /* in_from */
 	}
 
@@ -823,8 +845,8 @@ parse_statement(StatementClass *stmt)
 			col_stmt = (StatementClass *) hcol_stmt;
 			col_stmt->internal = TRUE;
 
-			result = PGAPI_Columns(hcol_stmt, "", 0, "", 0,
-						ti[i]->name, (SWORD) strlen(ti[i]->name), "", 0, PODBC_NOT_SEARCH_PATTERN);
+			result = PGAPI_Columns(hcol_stmt, "", 0, ti[i]->schema,
+					 SQL_NTS, ti[i]->name, SQL_NTS, "", 0, PODBC_NOT_SEARCH_PATTERN);
 
 			mylog("        Past PG_Columns\n");
 			if (result == SQL_SUCCESS)

src/interfaces/odbc/psqlodbc.h

@@ -5,7 +5,7 @@
  *
  * Comments:		See "notice.txt" for copyright and license information.
  *
- * $Id: psqlodbc.h,v 1.62 2002/04/01 03:01:15 inoue Exp $
+ * $Id: psqlodbc.h,v 1.63 2002/04/02 10:50:49 inoue Exp $
  *
  */
 

src/interfaces/odbc/socket.c

@@ -107,7 +107,6 @@ char
 SOCK_connect_to(SocketClass *self, unsigned short port, char *hostname)
 {
 	struct hostent *host;
-	struct sockaddr_in sadr;
 	unsigned long iaddr;
 
 	if (self->socket != -1)
@@ -117,7 +116,7 @@ SOCK_connect_to(SocketClass *self, unsigned short port, char *hostname)
 		return 0;
 	}
 
-	memset((char *) &sadr, 0, sizeof(sadr));
+	memset((char *) &(self->sadr), 0, sizeof(self->sadr));
 
 	/*
 	 * If it is a valid IP address, use it. Otherwise use hostname lookup.
@@ -132,13 +131,13 @@ SOCK_connect_to(SocketClass *self, unsigned short port, char *hostname)
 			self->errormsg = "Could not resolve hostname.";
 			return 0;
 		}
-		memcpy(&(sadr.sin_addr), host->h_addr, host->h_length);
+		memcpy(&(self->sadr.sin_addr), host->h_addr, host->h_length);
 	}
 	else
-		memcpy(&(sadr.sin_addr), (struct in_addr *) & iaddr, sizeof(iaddr));
+		memcpy(&(self->sadr.sin_addr), (struct in_addr *) & iaddr, sizeof(iaddr));
 
-	sadr.sin_family = AF_INET;
-	sadr.sin_port = htons(port);
+	self->sadr.sin_family = AF_INET;
+	self->sadr.sin_port = htons(port);
 
 	self->socket = socket(AF_INET, SOCK_STREAM, 0);
 	if (self->socket == -1)
@@ -148,8 +147,8 @@ SOCK_connect_to(SocketClass *self, unsigned short port, char *hostname)
 		return 0;
 	}
 
-	if (connect(self->socket, (struct sockaddr *) & (sadr),
-				sizeof(sadr)) < 0)
+	if (connect(self->socket, (struct sockaddr *) & (self->sadr),
+				sizeof(self->sadr)) < 0)
 	{
 		self->errornumber = SOCKET_COULD_NOT_CONNECT;
 		self->errormsg = "Could not connect to remote socket.";

src/interfaces/odbc/socket.h

@@ -61,6 +61,7 @@ struct SocketClass_
 
 	char	   *errormsg;
 	int			errornumber;
+	struct sockaddr_in	sadr; /* Used for handling connections for cancel */
 
 	char		reverse;		/* used to handle Postgres 6.2 protocol
 								 * (reverse byte order) */