Change nextval and other sequence functions to specify their sequence

argument as a 'regclass' value instead of a text string.  The frontend
conversion of text string to pg_class OID is now encapsulated as an
implicitly-invocable coercion from text to regclass.  This provides
backwards compatibility to the old behavior when the sequence argument
is explicitly typed as 'text'.  When the argument is just an unadorned
literal string, it will be taken as 'regclass', which means that the
stored representation will be an OID.  This solves longstanding problems
with renaming sequences that are referenced in default expressions, as
well as new-in-8.1 problems with renaming such sequences' schemas or
moving them to another schema.  All per recent discussion.
Along the way, fix some rather serious problems in dbmirror's support
for mirroring sequence operations (int4 vs int8 confusion for instance).

Author: tglsfdc

contrib/dbmirror/MirrorSetup.sql

@@ -2,7 +2,7 @@ BEGIN;
 
 
 CREATE FUNCTION "recordchange" () RETURNS trigger AS
-'$libdir/pending.so', 'recordchange' LANGUAGE 'C';
+'$libdir/pending', 'recordchange' LANGUAGE 'C';
 
 
 
@@ -48,15 +48,15 @@ CASCADE ON DELETE CASCADE
 
 UPDATE pg_proc SET proname='nextval_pg' WHERE proname='nextval';
 
-CREATE FUNCTION pg_catalog.nextval(text) RETURNS int8  AS
-'$libdir/pending.so', 'nextval' LANGUAGE 'C' STRICT;
+CREATE FUNCTION pg_catalog.nextval(regclass) RETURNS int8 AS
+  '$libdir/pending', 'nextval_mirror' LANGUAGE 'C' STRICT;
 
 
 UPDATE pg_proc set proname='setval_pg' WHERE proname='setval';
 
-CREATE FUNCTION pg_catalog.setval("unknown",integer,boolean) RETURNS int8  AS
-'$libdir/pending.so', 'setval' LANGUAGE 'C' STRICT;
-CREATE FUNCTION pg_catalog.setval("unknown",integer) RETURNS int8  AS
-'$libdir/pending.so', 'setval' LANGUAGE 'C' STRICT;
+CREATE FUNCTION pg_catalog.setval(regclass, int8, boolean) RETURNS int8 AS
+  '$libdir/pending', 'setval3_mirror' LANGUAGE 'C' STRICT;
+CREATE FUNCTION pg_catalog.setval(regclass, int8) RETURNS int8 AS
+  '$libdir/pending', 'setval_mirror' LANGUAGE 'C' STRICT;
 
 COMMIT;

contrib/dbmirror/README.dbmirror

@@ -56,7 +56,7 @@ Pending tables.
 
 Requirements:
 ---------------------------------
--PostgreSQL-7.4 (Older versions are no longer supported)
+-PostgreSQL-8.1 (Older versions are no longer supported)
 -Perl 5.6 or 5.8 (Other versions might work)
 -PgPerl (http://gborg.postgresql.org/project/pgperl/projdisplay.php)
 
@@ -177,15 +177,15 @@ If you are starting with an empty master database then the slave should
 be empty as well.  Otherwise use pg_dump to ensure that the slave database
 tables are initially identical to the master.
 
-6) Add entries in the MirrorHost table.
+6) Add entries in the dbmirror_MirrorHost table.
 
-Each slave database must have an entry in the MirrorHost table.
+Each slave database must have an entry in the dbmirror_MirrorHost table.
 
-The name of the host in the MirrorHost table must exactly match the
+The name of the host in the dbmirror_MirrorHost table must exactly match the
 slaveHost variable for that slave in the configuration file.
 
 For example
-INSERT INTO "MirrorHost" ("SlaveName") VALUES ('backup_system');
+INSERT INTO dbmirror_MirrorHost (SlaveName) VALUES ('backup_system');
 
 
 6)  Start DBMirror.pl

contrib/dbmirror/pending.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * pending.c
- * $Id: pending.c,v 1.21 2005/03/29 00:16:48 tgl Exp $
- * $PostgreSQL: pgsql/contrib/dbmirror/pending.c,v 1.21 2005/03/29 00:16:48 tgl Exp $
+ * $Id: pending.c,v 1.22 2005/10/02 23:50:05 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/dbmirror/pending.c,v 1.22 2005/10/02 23:50:05 tgl Exp $
  *
  * This file contains a trigger for Postgresql-7.x to record changes to tables
  * to a pending table for mirroring.
@@ -30,12 +30,13 @@
  *
  *
  ***************************************************************************/
-#include <postgres.h>
+#include "postgres.h"
 
-#include <executor/spi.h>
-#include <commands/trigger.h>
-#include <utils/lsyscache.h>
-#include <utils/array.h>
+#include "executor/spi.h"
+#include "commands/sequence.h"
+#include "commands/trigger.h"
+#include "utils/lsyscache.h"
+#include "utils/array.h"
 
 enum FieldUsage
 {
@@ -81,11 +82,11 @@ PG_FUNCTION_INFO_V1(recordchange);
 
 
 
-extern Datum nextval(PG_FUNCTION_ARGS);
-extern Datum setval(PG_FUNCTION_ARGS);
+extern Datum setval_mirror(PG_FUNCTION_ARGS);
+extern Datum setval3_mirror(PG_FUNCTION_ARGS);
+extern Datum nextval_mirror(PG_FUNCTION_ARGS);
 
-int saveSequenceUpdate(const text *sequenceName,
-				   int nextSequenceValue);
+static void saveSequenceUpdate(Oid relid, int64 nextValue, bool iscalled);
 
 
 /*****************************************************************************
@@ -310,11 +311,9 @@ storeKeyInfo(char *cpTableName, HeapTuple tTupleData,
 		SPI_pfree(cpKeyData);
 
 	if (iRetCode != SPI_OK_INSERT)
-	{
-		ereport(ERROR, (errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION)
-						,errmsg("error inserting row in pendingDelete")));
-		return -1;
-	}
+		ereport(ERROR,
+				(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
+				 errmsg("error inserting row in pendingDelete")));
 
 	debug_msg("insert successful");
 
@@ -583,161 +582,75 @@ packageData(HeapTuple tTupleData, TupleDesc tTupleDesc, Oid tableOid,
 }
 
 
-PG_FUNCTION_INFO_V1(setval);
+/*
+ * Support for mirroring sequence objects.
+ */
+
+PG_FUNCTION_INFO_V1(setval_mirror);
 
 Datum
-setval(PG_FUNCTION_ARGS)
+setval_mirror(PG_FUNCTION_ARGS)
 {
+	Oid			relid = PG_GETARG_OID(0);
+	int64		next = PG_GETARG_INT64(1);
+	int64		result;
 
+	result = DatumGetInt64(DirectFunctionCall2(setval_oid,
+											   ObjectIdGetDatum(relid),
+											   Int64GetDatum(next)));
 
-	text	   *sequenceName;
-
-	Oid			setvalArgTypes[3] = {TEXTOID, INT4OID,BOOLOID};
-	int			nextValue;
-	void	   *setvalPlan = NULL;
-	Datum		setvalData[3];
-	const char *setvalQuery = "SELECT setval_pg($1,$2,$3)";
-	int			ret;
-        char                    is_called;
-
-	sequenceName = PG_GETARG_TEXT_P(0);
-	nextValue = PG_GETARG_INT32(1);
-	is_called = PG_GETARG_BOOL(2);
-
-	setvalData[0] = PointerGetDatum(sequenceName);
-	setvalData[1] = Int32GetDatum(nextValue);
-	if(PG_NARGS() > 2)
-	  {
-	    setvalData[2] = BoolGetDatum(is_called);
-	  }
-	else
-	  {
-	    setvalData[2]=1;
-	  }
-
-	if (SPI_connect() < 0)
-	{
-		ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
-					errmsg("dbmirror:setval could not connect to SPI")));
-		return -1;
-	}
-
-	setvalPlan = SPI_prepare(setvalQuery, 3, setvalArgTypes);
-	if (setvalPlan == NULL)
-	{
-		ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
-					  errmsg("dbmirror:setval could not prepare plan")));
-		return -1;
-	}
-
-	ret = SPI_execp(setvalPlan, setvalData, NULL, 1);
-
-	if (ret != SPI_OK_SELECT || SPI_processed != 1)
-		return -1;
-
-	debug_msg2("dbmirror:setval: setval_pg returned ok:%d", nextValue);
-
-	ret = saveSequenceUpdate(sequenceName, nextValue);
-
-	SPI_pfree(setvalPlan);
-
-	SPI_finish();
-	debug_msg("dbmirror:setval about to return");
-	return Int64GetDatum(nextValue);
+	saveSequenceUpdate(relid, result, true);
 
+	PG_RETURN_INT64(result);
 }
 
-
-
-PG_FUNCTION_INFO_V1(nextval);
+PG_FUNCTION_INFO_V1(setval3_mirror);
 
 Datum
-nextval(PG_FUNCTION_ARGS)
+setval3_mirror(PG_FUNCTION_ARGS)
 {
-	text	   *sequenceName;
-
-	const char *nextvalQuery = "SELECT nextval_pg($1)";
-	Oid			nextvalArgTypes[1] = {TEXTOID};
-	void	   *nextvalPlan = NULL;
-	Datum		nextvalData[1];
-
-
-	int			ret;
-	HeapTuple	resTuple;
-	char		isNull;
-	int			nextSequenceValue;
-
-
-
-	debug_msg("dbmirror:nextval Starting pending.so:nextval");
-
-
-	sequenceName = PG_GETARG_TEXT_P(0);
-
-	if (SPI_connect() < 0)
-	{
-		ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
-				   errmsg("dbmirror:nextval could not connect to SPI")));
-		return -1;
-	}
-
-	nextvalPlan = SPI_prepare(nextvalQuery, 1, nextvalArgTypes);
-
-
-	debug_msg("prepared plan to call nextval_pg");
-
-
-	if (nextvalPlan == NULL)
-	{
-		ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
-						errmsg("dbmirror:nextval error creating plan")));
-		return -1;
-	}
-	nextvalData[0] = PointerGetDatum(sequenceName);
-
-	ret = SPI_execp(nextvalPlan, nextvalData, NULL, 1);
-
-	debug_msg("dbmirror:Executed call to nextval_pg");
-
-
-	if (ret != SPI_OK_SELECT || SPI_processed != 1)
-		return -1;
-
-	resTuple = SPI_tuptable->vals[0];
+	Oid			relid = PG_GETARG_OID(0);
+	int64		next = PG_GETARG_INT64(1);
+	bool		iscalled = PG_GETARG_BOOL(2);
+	int64		result;
 
-	debug_msg("dbmirror:nextval Set resTuple");
-
-	nextSequenceValue = *(unsigned int *) (DatumGetPointer(SPI_getbinval(resTuple,
-												   SPI_tuptable->tupdesc,
-														   1, &isNull)));
+	result = DatumGetInt64(DirectFunctionCall3(setval3_oid,
+											   ObjectIdGetDatum(relid),
+											   Int64GetDatum(next),
+											   BoolGetDatum(iscalled)));
 
+	saveSequenceUpdate(relid, result, iscalled);
 
+	PG_RETURN_INT64(result);
+}
 
-	debug_msg2("dbmirror:nextval Set SPI_getbinval:%d", nextSequenceValue);
+PG_FUNCTION_INFO_V1(nextval_mirror);
 
+Datum
+nextval_mirror(PG_FUNCTION_ARGS)
+{
+	Oid			relid = PG_GETARG_OID(0);
+	int64		result;
 
-	saveSequenceUpdate(sequenceName, nextSequenceValue);
-	SPI_pfree(resTuple);
-	SPI_pfree(nextvalPlan);
+	result = DatumGetInt64(DirectFunctionCall1(nextval_oid,
+											   ObjectIdGetDatum(relid)));
 
-	SPI_finish();
+	saveSequenceUpdate(relid, result, true);
 
-	return Int64GetDatum(nextSequenceValue);
+	PG_RETURN_INT64(result);
 }
 
 
-int
-saveSequenceUpdate(const text *sequenceName,
-				   int nextSequenceVal)
+static void
+saveSequenceUpdate(Oid relid, int64 nextValue, bool iscalled)
 {
-
-	Oid			insertArgTypes[2] = {TEXTOID, INT4OID};
+	Oid			insertArgTypes[2] = {NAMEOID, INT4OID};
 	Oid			insertDataArgTypes[1] = {NAMEOID};
-	void	   *insertPlan = NULL;
-	void	   *insertDataPlan = NULL;
+	void	   *insertPlan;
+	void	   *insertDataPlan;
 	Datum		insertDatum[2];
 	Datum		insertDataDatum[1];
-	char		nextSequenceText[32];
+	char		nextSequenceText[64];
 
 	const char *insertQuery =
 	"INSERT INTO dbmirror_Pending (TableName,Op,XID) VALUES" \
@@ -746,36 +659,50 @@ saveSequenceUpdate(const text *sequenceName,
 	"INSERT INTO dbmirror_PendingData(SeqId,IsKey,Data) VALUES " \
 	"(currval('dbmirror_pending_seqid_seq'),'t',$1)";
 
-	int			ret;
-
+	if (SPI_connect() < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("dbmirror:savesequenceupdate could not connect to SPI")));
 
 	insertPlan = SPI_prepare(insertQuery, 2, insertArgTypes);
 	insertDataPlan = SPI_prepare(insertDataQuery, 1, insertDataArgTypes);
 
-	debug_msg("Prepared insert query");
-
-
 	if (insertPlan == NULL || insertDataPlan == NULL)
-		ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION), errmsg("dbmirror:nextval error creating plan")));
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("dbmirror:savesequenceupdate error creating plan")));
 
+	insertDatum[0] = PointerGetDatum(get_rel_name(relid));
 	insertDatum[1] = Int32GetDatum(GetCurrentTransactionId());
-	insertDatum[0] = PointerGetDatum(sequenceName);
 
-	sprintf(nextSequenceText, "%d", nextSequenceVal);
+	snprintf(nextSequenceText, sizeof(nextSequenceText),
+			 INT64_FORMAT ",'%c'",
+			 nextValue, iscalled ? 't' : 'f');
+
+	/*
+	 * note type cheat here: we prepare a C string and then claim it is a
+	 * NAME, which the system will coerce to varchar for us.
+	 */
 	insertDataDatum[0] = PointerGetDatum(nextSequenceText);
-	debug_msg2("dbmirror:savesequenceupdate: Setting value %s",
+
+	debug_msg2("dbmirror:savesequenceupdate: Setting value as %s",
 			   nextSequenceText);
 
 	debug_msg("dbmirror:About to execute insert query");
 
-	ret = SPI_execp(insertPlan, insertDatum, NULL, 1);
+	if (SPI_execp(insertPlan, insertDatum, NULL, 1) != SPI_OK_INSERT)
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("error inserting row in dbmirror_Pending")));
 
-	ret = SPI_execp(insertDataPlan, insertDataDatum, NULL, 1);
+	if (SPI_execp(insertDataPlan, insertDataDatum, NULL, 1) != SPI_OK_INSERT)
+		ereport(ERROR,
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("error inserting row in dbmirror_PendingData")));
 
 	debug_msg("dbmirror:Insert query finished");
 	SPI_pfree(insertPlan);
 	SPI_pfree(insertDataPlan);
 
-	return ret;
-
+	SPI_finish();
 }