Utilize the visibility map in autovacuum, too. There was an oversight in

the visibility map patch that because autovacuum always sets
VacuumStmt->freeze_min_age, visibility map was never used for autovacuum,
only for manually launched vacuums. This patch introduces a new scan_all
field to VacuumStmt, indicating explicitly whether the visibility map
should be used, or the whole relation should be scanned, to advance
relfrozenxid. Anti-wraparound vacuums still need to scan all pages.

Author: hlinnaka

src/backend/commands/vacuumlazy.c

@@ -29,7 +29,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.112 2008/12/03 13:05:22 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.113 2008/12/04 11:42:23 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -143,7 +143,6 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
 	BlockNumber possibly_freeable;
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
-	bool		scan_all;
 
 	pg_rusage_init(&ru0);
 
@@ -169,15 +168,9 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
 	/* Open all indexes of the relation */
 	vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel);
 	vacrelstats->hasindex = (nindexes > 0);
-
-	/* Should we use the visibility map or scan all pages? */
-	if (vacstmt->freeze_min_age != -1)
-		scan_all = true;
-	else
-		scan_all = false;
 
 	/* Do the vacuuming */
-	lazy_scan_heap(onerel, vacrelstats, Irel, nindexes, scan_all);
+	lazy_scan_heap(onerel, vacrelstats, Irel, nindexes, vacstmt->scan_all);
 
 	/* Done with indexes */
 	vac_close_indexes(nindexes, Irel, NoLock);

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.413 2008/11/24 08:46:03 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.414 2008/12/04 11:42:23 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2771,6 +2771,7 @@ _copyVacuumStmt(VacuumStmt *from)
 	COPY_SCALAR_FIELD(analyze);
 	COPY_SCALAR_FIELD(verbose);
 	COPY_SCALAR_FIELD(freeze_min_age);
+	COPY_SCALAR_FIELD(scan_all);
 	COPY_NODE_FIELD(relation);
 	COPY_NODE_FIELD(va_cols);
 

src/backend/nodes/equalfuncs.c

@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.338 2008/11/24 08:46:03 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.339 2008/12/04 11:42:24 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1436,6 +1436,7 @@ _equalVacuumStmt(VacuumStmt *a, VacuumStmt *b)
 	COMPARE_SCALAR_FIELD(analyze);
 	COMPARE_SCALAR_FIELD(verbose);
 	COMPARE_SCALAR_FIELD(freeze_min_age);
+	COMPARE_SCALAR_FIELD(scan_all);
 	COMPARE_NODE_FIELD(relation);
 	COMPARE_NODE_FIELD(va_cols);
 

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.641 2008/11/26 08:45:11 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.642 2008/12/04 11:42:24 heikki Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -5837,6 +5837,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
 					n->analyze = false;
 					n->full = $2;
 					n->freeze_min_age = $3 ? 0 : -1;
+					n->scan_all = $3;
 					n->verbose = $4;
 					n->relation = NULL;
 					n->va_cols = NIL;
@@ -5849,6 +5850,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
 					n->analyze = false;
 					n->full = $2;
 					n->freeze_min_age = $3 ? 0 : -1;
+					n->scan_all = $3;
 					n->verbose = $4;
 					n->relation = $5;
 					n->va_cols = NIL;
@@ -5860,6 +5862,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose
 					n->vacuum = true;
 					n->full = $2;
 					n->freeze_min_age = $3 ? 0 : -1;
+					n->scan_all = $3;
 					n->verbose |= $4;
 					$$ = (Node *)n;
 				}

src/backend/postmaster/autovacuum.c

@@ -55,7 +55,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.87 2008/11/12 10:10:32 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.88 2008/12/04 11:42:24 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2649,6 +2649,7 @@ autovacuum_do_vac_analyze(autovac_table *tab,
 	vacstmt.full = false;
 	vacstmt.analyze = tab->at_doanalyze;
 	vacstmt.freeze_min_age = tab->at_freeze_min_age;
+	vacstmt.scan_all = tab->at_wraparound;
 	vacstmt.verbose = false;
 	vacstmt.relation = NULL;	/* not used since we pass a relid */
 	vacstmt.va_cols = NIL;

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.379 2008/11/24 08:46:04 petere Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.380 2008/12/04 11:42:24 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1966,6 +1966,7 @@ typedef struct VacuumStmt
 	bool		full;			/* do FULL (non-concurrent) vacuum */
 	bool		analyze;		/* do ANALYZE step */
 	bool		verbose;		/* print progress info */
+	bool		scan_all;		/* force scan of all pages */
 	int			freeze_min_age; /* min freeze age, or -1 to use default */
 	RangeVar   *relation;		/* single table to process, or NULL */
 	List	   *va_cols;		/* list of column names, or NIL for all */