Fix recently-understood problems with handling of XID freezing, particularly

in PITR scenarios.  We now WAL-log the replacement of old XIDs with
FrozenTransactionId, so that such replacement is guaranteed to propagate to
PITR slave databases.  Also, rather than relying on hint-bit updates to be
preserved, pg_clog is not truncated until all instances of an XID are known to
have been replaced by FrozenTransactionId.  Add new GUC variables and
pg_autovacuum columns to allow management of the freezing policy, so that
users can trade off the size of pg_clog against the amount of freezing work
done.  Revise the already-existing code that forces autovacuum of tables
approaching the wraparound point to make it more bulletproof; also, revise the
autovacuum logic so that anti-wraparound vacuuming is done per-table rather
than per-database.  initdb forced because of changes in pg_class, pg_database,
and pg_autovacuum catalogs.  Heikki Linnakangas, Simon Riggs, and Tom Lane.

6 files changed, 44 insertions, 11 deletions

diff --git a/src/include/access/clog.h b/src/include/access/clog.h
index 999f15bdf7f..0cb76000a29 100644
--- a/src/include/access/clog.h
+++ b/src/include/access/clog.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/clog.h,v 1.17 2006/03/24 04:32:13 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/clog.h,v 1.18 2006/11/05 22:42:09 tgl Exp $
  */
 #ifndef CLOG_H
 #define CLOG_H
@@ -46,6 +46,7 @@ extern void TruncateCLOG(TransactionId oldestXact);
 
 /* XLOG stuff */
 #define CLOG_ZEROPAGE		0x00
+#define CLOG_TRUNCATE		0x10
 
 extern void clog_redo(XLogRecPtr lsn, XLogRecord *record);
 extern void clog_desc(StringInfo buf, uint8 xl_info, char *rec);
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index b2dd0f3390d..4b3dd57534c 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.116 2006/10/04 00:30:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.117 2006/11/05 22:42:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -170,6 +170,8 @@ extern HTSU_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
 				TransactionId *update_xmax, CommandId cid,
 				LockTupleMode mode, bool nowait);
 extern void heap_inplace_update(Relation relation, HeapTuple tuple);
+extern bool heap_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
+							  Buffer buf);
 
 extern Oid	simple_heap_insert(Relation relation, HeapTuple tup);
 extern void simple_heap_delete(Relation relation, ItemPointer tid);
@@ -181,11 +183,17 @@ extern void heap_restrpos(HeapScanDesc scan);
 
 extern void heap_redo(XLogRecPtr lsn, XLogRecord *rptr);
 extern void heap_desc(StringInfo buf, uint8 xl_info, char *rec);
-extern XLogRecPtr log_heap_clean(Relation reln, Buffer buffer,
-			   OffsetNumber *unused, int uncnt);
+extern void heap2_redo(XLogRecPtr lsn, XLogRecord *rptr);
+extern void heap2_desc(StringInfo buf, uint8 xl_info, char *rec);
+
 extern XLogRecPtr log_heap_move(Relation reln, Buffer oldbuf,
 			  ItemPointerData from,
 			  Buffer newbuf, HeapTuple newtup);
+extern XLogRecPtr log_heap_clean(Relation reln, Buffer buffer,
+			   OffsetNumber *unused, int uncnt);
+extern XLogRecPtr log_heap_freeze(Relation reln, Buffer buffer,
+								  TransactionId cutoff_xid,
+								  OffsetNumber *offsets, int offcnt);
 
 /* in common/heaptuple.c */
 extern Size heap_compute_data_size(TupleDesc tupleDesc,
diff --git a/src/include/access/htup.h b/src/include/access/htup.h
index edfce82bc04..ed1f082de05 100644
--- a/src/include/access/htup.h
+++ b/src/include/access/htup.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.86 2006/10/04 00:30:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.87 2006/11/05 22:42:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -510,6 +510,13 @@ typedef HeapTupleData *HeapTuple;
  * we can (and we do) restore entire page in redo
  */
 #define XLOG_HEAP_INIT_PAGE 0x80
+/*
+ * We ran out of opcodes, so heapam.c now has a second RmgrId.  These opcodes
+ * are associated with RM_HEAP2_ID, but are not logically different from
+ * the ones above associated with RM_HEAP_ID.  We apply XLOG_HEAP_OPMASK,
+ * although currently XLOG_HEAP_INIT_PAGE is not used for any of these.
+ */
+#define XLOG_HEAP2_FREEZE	0x00
 
 /*
  * All what we need to find changed tuple
@@ -613,4 +620,15 @@ typedef struct xl_heap_inplace
 
 #define SizeOfHeapInplace	(offsetof(xl_heap_inplace, target) + SizeOfHeapTid)
 
+/* This is what we need to know about tuple freezing during vacuum */
+typedef struct xl_heap_freeze
+{
+	RelFileNode node;
+	BlockNumber block;
+	TransactionId cutoff_xid;
+	/* TUPLE OFFSET NUMBERS FOLLOW AT THE END */
+} xl_heap_freeze;
+
+#define SizeOfHeapFreeze (offsetof(xl_heap_freeze, cutoff_xid) + sizeof(TransactionId))
+
 #endif   /* HTUP_H */
diff --git a/src/include/access/rmgr.h b/src/include/access/rmgr.h
index 471b0cfb764..7be2dfc9f65 100644
--- a/src/include/access/rmgr.h
+++ b/src/include/access/rmgr.h
@@ -3,7 +3,7 @@
  *
  * Resource managers definition
  *
- * $PostgreSQL: pgsql/src/include/access/rmgr.h,v 1.16 2006/05/02 11:28:55 teodor Exp $
+ * $PostgreSQL: pgsql/src/include/access/rmgr.h,v 1.17 2006/11/05 22:42:10 tgl Exp $
  */
 #ifndef RMGR_H
 #define RMGR_H
@@ -12,6 +12,9 @@ typedef uint8 RmgrId;
 
 /*
  * Built-in resource managers
+ *
+ * Note: RM_MAX_ID could be as much as 255 without breaking the XLOG file
+ * format, but we keep it small to minimize the size of RmgrTable[].
  */
 #define RM_XLOG_ID				0
 #define RM_XACT_ID				1
@@ -20,6 +23,7 @@ typedef uint8 RmgrId;
 #define RM_DBASE_ID				4
 #define RM_TBLSPC_ID			5
 #define RM_MULTIXACT_ID			6
+#define RM_HEAP2_ID				9
 #define RM_HEAP_ID				10
 #define RM_BTREE_ID				11
 #define RM_HASH_ID				12
diff --git a/src/include/access/transam.h b/src/include/access/transam.h
index f1b91145f67..96cc65f94d5 100644
--- a/src/include/access/transam.h
+++ b/src/include/access/transam.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/transam.h,v 1.58 2006/07/10 16:20:51 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/transam.h,v 1.59 2006/11/05 22:42:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -23,7 +23,7 @@
  * always be considered valid.
  *
  * FirstNormalTransactionId is the first "normal" transaction id.
- * Note: if you need to change it, you must change it in pg_class.h as well.
+ * Note: if you need to change it, you must change pg_class.h as well.
  * ----------------
  */
 #define InvalidTransactionId		((TransactionId) 0)
@@ -88,6 +88,9 @@ typedef struct VariableCacheData
 	Oid			nextOid;		/* next OID to assign */
 	uint32		oidCount;		/* OIDs available before must do XLOG work */
 	TransactionId nextXid;		/* next XID to assign */
+
+	TransactionId oldestXid;	/* cluster-wide minimum datfrozenxid */
+	TransactionId xidVacLimit;	/* start forcing autovacuums here */
 	TransactionId xidWarnLimit; /* start complaining here */
 	TransactionId xidStopLimit; /* refuse to advance nextXid beyond here */
 	TransactionId xidWrapLimit; /* where the world ends */
@@ -124,7 +127,7 @@ extern bool TransactionIdFollowsOrEquals(TransactionId id1, TransactionId id2);
 /* in transam/varsup.c */
 extern TransactionId GetNewTransactionId(bool isSubXact);
 extern TransactionId ReadNewTransactionId(void);
-extern void SetTransactionIdLimit(TransactionId oldest_datminxid,
+extern void SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
 					  Name oldest_datname);
 extern Oid	GetNewObjectId(void);
 
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index a5ae94b91aa..93c95aa4627 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.74 2006/08/21 16:16:31 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.75 2006/11/05 22:42:10 tgl Exp $
  */
 #ifndef XLOG_H
 #define XLOG_H
@@ -165,7 +165,6 @@ extern void InitXLOGAccess(void);
 extern void CreateCheckPoint(bool shutdown, bool force);
 extern void XLogPutNextOid(Oid nextOid);
 extern XLogRecPtr GetRedoRecPtr(void);
-extern TransactionId GetRecentNextXid(void);
 extern void GetNextXidAndEpoch(TransactionId *xid, uint32 *epoch);
 
 #endif   /* XLOG_H */