Change WAL-logging scheme for multixacts to be more like regular

transaction IDs, rather than like subtrans; in particular, the information
now survives a database restart.  Per previous discussion, this is
essential for PITR log shipping and for 2PC.

5 files changed, 43 insertions, 11 deletions

diff --git a/src/include/access/htup.h b/src/include/access/htup.h
index adeb05fd560..e394afd3139 100644
--- a/src/include/access/htup.h
+++ b/src/include/access/htup.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.74 2005/04/28 21:47:17 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.75 2005/06/08 15:50:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -505,6 +505,8 @@ typedef struct xl_heap_newpage
 typedef struct xl_heap_lock
 {
 	xl_heaptid	target;			/* locked tuple id */
+	TransactionId locking_xid;	/* might be a MultiXactId not xid */
+	bool		xid_is_mxact;	/* is it? */
 	bool		shared_lock;	/* shared or exclusive row lock? */
 } xl_heap_lock;
 
diff --git a/src/include/access/multixact.h b/src/include/access/multixact.h
index 65d19704c40..2199b05f2c5 100644
--- a/src/include/access/multixact.h
+++ b/src/include/access/multixact.h
@@ -6,16 +6,38 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/multixact.h,v 1.2 2005/05/03 19:42:41 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/multixact.h,v 1.3 2005/06/08 15:50:28 tgl Exp $
  */
 #ifndef MULTIXACT_H
 #define MULTIXACT_H
 
+#include "access/xlog.h"
+
 #define InvalidMultiXactId	((MultiXactId) 0)
 #define FirstMultiXactId	((MultiXactId) 1)
 
 #define MultiXactIdIsValid(multi) ((multi) != InvalidMultiXactId)
 
+/* ----------------
+ *		multixact-related XLOG entries
+ * ----------------
+ */
+
+#define XLOG_MULTIXACT_ZERO_OFF_PAGE	0x00
+#define XLOG_MULTIXACT_ZERO_MEM_PAGE	0x10
+#define XLOG_MULTIXACT_CREATE_ID		0x20
+
+typedef struct xl_multixact_create
+{
+	MultiXactId		mid;		/* new MultiXact's ID */
+	MultiXactOffset	moff;		/* its starting offset in members file */
+	int32			nxids;		/* number of member XIDs */
+	TransactionId	xids[1];	/* VARIABLE LENGTH ARRAY */
+} xl_multixact_create;
+
+#define MinSizeOfMultiXactCreate offsetof(xl_multixact_create, xids)
+
+
 extern MultiXactId MultiXactIdCreate(TransactionId xid1, TransactionId xid2);
 extern MultiXactId MultiXactIdExpand(MultiXactId multi, TransactionId xid);
 extern bool MultiXactIdIsRunning(MultiXactId multi);
@@ -29,9 +51,16 @@ extern void MultiXactShmemInit(void);
 extern void BootStrapMultiXact(void);
 extern void StartupMultiXact(void);
 extern void ShutdownMultiXact(void);
-extern MultiXactId MultiXactGetCheckptMulti(bool is_shutdown);
+extern void MultiXactGetCheckptMulti(bool is_shutdown,
+									 MultiXactId *nextMulti,
+									 MultiXactOffset *nextMultiOffset);
 extern void CheckPointMultiXact(void);
-extern void MultiXactSetNextMXact(MultiXactId nextMulti);
-extern void MultiXactAdvanceNextMXact(MultiXactId minMulti);
+extern void MultiXactSetNextMXact(MultiXactId nextMulti,
+								  MultiXactOffset nextMultiOffset);
+extern void MultiXactAdvanceNextMXact(MultiXactId minMulti,
+									  MultiXactOffset minMultiOffset);
+
+extern void multixact_redo(XLogRecPtr lsn, XLogRecord *record);
+extern void multixact_desc(char *buf, uint8 xl_info, char *rec);
 
 #endif   /* MULTIXACT_H */
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 7547d7f5b9f..ead4619b027 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.64 2005/06/06 20:22:58 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.65 2005/06/08 15:50:28 tgl Exp $
  */
 #ifndef XLOG_H
 #define XLOG_H
@@ -165,7 +165,6 @@ extern void ShutdownXLOG(int code, Datum arg);
 extern void InitXLOGAccess(void);
 extern void CreateCheckPoint(bool shutdown, bool force);
 extern void XLogPutNextOid(Oid nextOid);
-extern void XLogPutNextMultiXactId(MultiXactId multi);
 extern XLogRecPtr GetRedoRecPtr(void);
 
 #endif   /* XLOG_H */
diff --git a/src/include/c.h b/src/include/c.h
index 6318c5573dd..1a920387747 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/c.h,v 1.184 2005/05/25 21:40:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/c.h,v 1.185 2005/06/08 15:50:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -388,6 +388,8 @@ typedef uint32 SubTransactionId;
 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
 typedef TransactionId MultiXactId;
 
+typedef uint32 MultiXactOffset;
+
 typedef uint32 CommandId;
 
 #define FirstCommandId	((CommandId) 0)
diff --git a/src/include/catalog/pg_control.h b/src/include/catalog/pg_control.h
index 3f96b6bf261..73f32b55ade 100644
--- a/src/include/catalog/pg_control.h
+++ b/src/include/catalog/pg_control.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_control.h,v 1.22 2005/06/02 05:55:29 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_control.h,v 1.23 2005/06/08 15:50:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -22,7 +22,7 @@
 
 
 /* Version identifier for this pg_control format */
-#define PG_CONTROL_VERSION	810
+#define PG_CONTROL_VERSION	811
 
 /*
  * Body of CheckPoint XLOG records.  This is declared here because we keep
@@ -40,13 +40,13 @@ typedef struct CheckPoint
 	TransactionId nextXid;		/* next free XID */
 	Oid			nextOid;		/* next free OID */
 	MultiXactId	nextMulti;		/* next free MultiXactId */
+	MultiXactOffset nextMultiOffset;	/* next free MultiXact offset */
 	time_t		time;			/* time stamp of checkpoint */
 } CheckPoint;
 
 /* XLOG info values for XLOG rmgr */
 #define XLOG_CHECKPOINT_SHUTDOWN		0x00
 #define XLOG_CHECKPOINT_ONLINE			0x10
-#define XLOG_NEXTMULTI					0x20
 #define XLOG_NEXTOID					0x30