slru_startup.v3.patch

*** a/src/backend/access/transam/clog.c
--- b/src/backend/access/transam/clog.c
***************
*** 489,494 **** StartupCLOG(void)
--- 489,513 ----
  	 */
  	ClogCtl->shared->latest_page_number = pageno;
  
+ 	LWLockRelease(CLogControlLock);
+ }
+ 
+ /*
+  * This must be called ONCE at the end of startup/recovery.
+  */
+ void
+ TrimCLOG(void)
+ {
+ 	TransactionId xid = ShmemVariableCache->nextXid;
+ 	int			pageno = TransactionIdToPage(xid);
+ 
+ 	LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
+ 
+ 	/*
+ 	 * Re-Initialize our idea of the latest page number.
+ 	 */
+ 	ClogCtl->shared->latest_page_number = pageno;
+ 
  	/*
  	 * Zero out the remainder of the current clog page.  Under normal
  	 * circumstances it should be zeroes already, but it seems at least
*** a/src/backend/access/transam/multixact.c
--- b/src/backend/access/transam/multixact.c
***************
*** 1567,1573 **** StartupMultiXact(void)
  
  	/*
  	 * Zero out the remainder of the current members page.	See notes in
! 	 * StartupCLOG() for motivation.
  	 */
  	entryno = MXOffsetToMemberEntry(offset);
  	if (entryno != 0)
--- 1567,1573 ----
  
  	/*
  	 * Zero out the remainder of the current members page.	See notes in
! 	 * TrimCLOG() for motivation.
  	 */
  	entryno = MXOffsetToMemberEntry(offset);
  	if (entryno != 0)
*** a/src/backend/access/transam/xlog.c
--- b/src/backend/access/transam/xlog.c
***************
*** 6410,6419 **** StartupXLOG(void)
  				oldestActiveXID = checkPoint.oldestActiveXid;
  			Assert(TransactionIdIsValid(oldestActiveXID));
  
! 			/* Startup commit log and related stuff */
  			StartupCLOG();
  			StartupSUBTRANS(oldestActiveXID);
- 			StartupMultiXact();
  
  			/*
  			 * If we're beginning at a shutdown checkpoint, we know that
--- 6410,6421 ----
  				oldestActiveXID = checkPoint.oldestActiveXid;
  			Assert(TransactionIdIsValid(oldestActiveXID));
  
! 			/*
! 			 * Startup commit log and subtrans only. Other SLRUs are not
! 			 * maintained during recovery and need not be started yet.
! 			 */
  			StartupCLOG();
  			StartupSUBTRANS(oldestActiveXID);
  
  			/*
  			 * If we're beginning at a shutdown checkpoint, we know that
***************
*** 6914,6929 **** StartupXLOG(void)
  	TransactionIdRetreat(ShmemVariableCache->latestCompletedXid);
  
  	/*
! 	 * Start up the commit log and related stuff, too. In hot standby mode we
! 	 * did this already before WAL replay.
  	 */
  	if (standbyState == STANDBY_DISABLED)
  	{
  		StartupCLOG();
  		StartupSUBTRANS(oldestActiveXID);
- 		StartupMultiXact();
  	}
  
  	/* Reload shared-memory state for prepared transactions */
  	RecoverPreparedTransactions();
  
--- 6916,6936 ----
  	TransactionIdRetreat(ShmemVariableCache->latestCompletedXid);
  
  	/*
! 	 * Start up the commit log and subtrans, if not already done for
! 	 * hot standby.
  	 */
  	if (standbyState == STANDBY_DISABLED)
  	{
  		StartupCLOG();
  		StartupSUBTRANS(oldestActiveXID);
  	}
  
+ 	/*
+ 	 * Perform end of recovery actions for any SLRUs that need it.
+ 	 */
+ 	StartupMultiXact();
+ 	TrimCLOG();
+ 
  	/* Reload shared-memory state for prepared transactions */
  	RecoverPreparedTransactions();
  
*** a/src/include/access/clog.h
--- b/src/include/access/clog.h
***************
*** 40,45 **** extern Size CLOGShmemSize(void);
--- 40,46 ----
  extern void CLOGShmemInit(void);
  extern void BootStrapCLOG(void);
  extern void StartupCLOG(void);
+ extern void TrimCLOG(void);
  extern void ShutdownCLOG(void);
  extern void CheckPointCLOG(void);
  extern void ExtendCLOG(TransactionId newestXact);