diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index f5e3ad8e199023fba6fd0ef85bc831c6b2e4d053..e18a7de2d07ec4a5e01d9c55b18f0aaa30e44730 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.117 2002/03/06 06:09:21 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.118 2002/03/15 19:20:29 tgl Exp $
*
* NOTES
* Transaction aborts can now occur two ways:
@@ -546,32 +546,48 @@ RecordTransactionCommit(void)
xid = GetCurrentTransactionId();
/*
- * We needn't write anything in xlog or clog if the transaction was
- * read-only, which we check by testing if it made any xlog entries.
+ * We only need to log the commit in xlog and clog if the transaction made
+ * any transaction-controlled XLOG entries. (Otherwise, its XID appears
+ * nowhere in permanent storage, so no one will ever care if it
+ * committed.) However, we must flush XLOG to disk if we made any XLOG
+ * entries, whether in or out of transaction control. For example, if we
+ * reported a nextval() result to the client, this ensures that any XLOG
+ * record generated by nextval will hit the disk before we report the
+ * transaction committed.
*/
- if (MyLastRecPtr.xrecoff != 0)
+ if (MyXactMadeXLogEntry)
{
- XLogRecData rdata;
- xl_xact_commit xlrec;
XLogRecPtr recptr;
BufmgrCommit();
- xlrec.xtime = time(NULL);
- rdata.buffer = InvalidBuffer;
- rdata.data = (char *) (&xlrec);
- rdata.len = SizeOfXactCommit;
- rdata.next = NULL;
-
START_CRIT_SECTION();
- /*
- * SHOULD SAVE ARRAY OF RELFILENODE-s TO DROP
- */
- recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, &rdata);
+ if (MyLastRecPtr.xrecoff != 0)
+ {
+ /* Need to emit a commit record */
+ XLogRecData rdata;
+ xl_xact_commit xlrec;
+
+ xlrec.xtime = time(NULL);
+ rdata.buffer = InvalidBuffer;
+ rdata.data = (char *) (&xlrec);
+ rdata.len = SizeOfXactCommit;
+ rdata.next = NULL;
+
+ /*
+ * XXX SHOULD SAVE ARRAY OF RELFILENODE-s TO DROP
+ */
+ recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, &rdata);
+ }
+ else
+ {
+ /* Just flush through last record written by me */
+ recptr = ProcLastRecEnd;
+ }
/*
- * Sleep before commit! So we can flush more than one commit
+ * Sleep before flush! So we can flush more than one commit
* records per single fsync. (The idea is some other backend may
* do the XLogFlush while we're sleeping. This needs work still,
* because on most Unixen, the minimum select() delay is 10msec or
@@ -593,15 +609,17 @@ RecordTransactionCommit(void)
XLogFlush(recptr);
- /* Break the chain of back-links in the XLOG records I output */
- MyLastRecPtr.xrecoff = 0;
-
- /* Mark the transaction committed in clog */
- TransactionIdCommit(xid);
+ /* Mark the transaction committed in clog, if needed */
+ if (MyLastRecPtr.xrecoff != 0)
+ TransactionIdCommit(xid);
END_CRIT_SECTION();
}
+ /* Break the chain of back-links in the XLOG records I output */
+ MyLastRecPtr.xrecoff = 0;
+ MyXactMadeXLogEntry = false;
+
/* Show myself as out of the transaction in PROC array */
MyProc->logRec.xrecoff = 0;
@@ -689,8 +707,11 @@ RecordTransactionAbort(void)
TransactionId xid = GetCurrentTransactionId();
/*
- * We needn't write anything in xlog or clog if the transaction was
- * read-only, which we check by testing if it made any xlog entries.
+ * We only need to log the abort in xlog and clog if the transaction made
+ * any transaction-controlled XLOG entries. (Otherwise, its XID appears
+ * nowhere in permanent storage, so no one will ever care if it
+ * committed.) We do not flush XLOG to disk in any case, since the
+ * default assumption after a crash would be that we aborted, anyway.
*
* Extra check here is to catch case that we aborted partway through
* RecordTransactionCommit ...
@@ -714,11 +735,6 @@ RecordTransactionAbort(void)
*/
recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, &rdata);
- /*
- * There's no need for XLogFlush here, since the default
- * assumption would be that we aborted, anyway.
- */
-
/* Mark the transaction aborted in clog */
TransactionIdAbort(xid);
@@ -727,6 +743,8 @@ RecordTransactionAbort(void)
/* Break the chain of back-links in the XLOG records I output */
MyLastRecPtr.xrecoff = 0;
+ MyXactMadeXLogEntry = false;
+
/* Show myself as out of the transaction in PROC array */
MyProc->logRec.xrecoff = 0;
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index add269577b64526db346c98ddae682c582d05c2d..7e29f6cd0265c39857db5d89cdeaf1e23c2638fa 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.89 2002/03/06 06:09:22 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.90 2002/03/15 19:20:30 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -131,27 +131,36 @@ bool InRecovery = false;
/*
* MyLastRecPtr points to the start of the last XLOG record inserted by the
- * current transaction. If MyLastRecPtr.xrecoff == 0, then we are not in
- * a transaction or the transaction has not yet made any loggable changes.
+ * current transaction. If MyLastRecPtr.xrecoff == 0, then the current
+ * xact hasn't yet inserted any transaction-controlled XLOG records.
*
* Note that XLOG records inserted outside transaction control are not
- * reflected into MyLastRecPtr.
+ * reflected into MyLastRecPtr. They do, however, cause MyXactMadeXLogEntry
+ * to be set true. The latter can be used to test whether the current xact
+ * made any loggable changes (including out-of-xact changes, such as
+ * sequence updates).
*/
XLogRecPtr MyLastRecPtr = {0, 0};
+bool MyXactMadeXLogEntry = false;
+
/*
* ProcLastRecPtr points to the start of the last XLOG record inserted by the
* current backend. It is updated for all inserts, transaction-controlled
- * or not.
+ * or not. ProcLastRecEnd is similar but points to end+1 of last record.
*/
static XLogRecPtr ProcLastRecPtr = {0, 0};
+XLogRecPtr ProcLastRecEnd = {0, 0};
+
/*
* RedoRecPtr is this backend's local copy of the REDO record pointer
* (which is almost but not quite the same as a pointer to the most recent
* CHECKPOINT record). We update this from the shared-memory copy,
* XLogCtl->Insert.RedoRecPtr, whenever we can safely do so (ie, when we
- * hold the Insert lock). See XLogInsert for details.
+ * hold the Insert lock). See XLogInsert for details. We are also allowed
+ * to update from XLogCtl->Insert.RedoRecPtr if we hold the info_lck;
+ * see GetRedoRecPtr.
*/
static XLogRecPtr RedoRecPtr;
@@ -272,7 +281,8 @@ typedef struct XLogCtlData
StartUpID ThisStartUpID;
/* This value is not protected by *any* lock... */
- XLogRecPtr RedoRecPtr; /* see SetRedoRecPtr/GetRedoRecPtr */
+ /* see SetSavedRedoRecPtr/GetSavedRedoRecPtr */
+ XLogRecPtr SavedRedoRecPtr;
slock_t info_lck; /* locks shared LogwrtRqst/LogwrtResult */
} XLogCtlData;
@@ -777,6 +787,7 @@ begin:;
MyLastRecPtr = RecPtr;
ProcLastRecPtr = RecPtr;
Insert->PrevRecord = RecPtr;
+ MyXactMadeXLogEntry = true;
Insert->currpos += SizeOfXLogRecord;
freespace -= SizeOfXLogRecord;
@@ -855,6 +866,8 @@ begin:;
SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
}
+ ProcLastRecEnd = RecPtr;
+
END_CRIT_SECTION();
return (RecPtr);
@@ -2538,7 +2551,7 @@ StartupXLOG(void)
ThisStartUpID = checkPoint.ThisStartUpID;
RedoRecPtr = XLogCtl->Insert.RedoRecPtr =
- XLogCtl->RedoRecPtr = checkPoint.redo;
+ XLogCtl->SavedRedoRecPtr = checkPoint.redo;
if (XLByteLT(RecPtr, checkPoint.redo))
elog(PANIC, "invalid redo in checkpoint record");
@@ -2824,32 +2837,47 @@ void
SetThisStartUpID(void)
{
ThisStartUpID = XLogCtl->ThisStartUpID;
- RedoRecPtr = XLogCtl->RedoRecPtr;
+ RedoRecPtr = XLogCtl->SavedRedoRecPtr;
}
/*
* CheckPoint process called by postmaster saves copy of new RedoRecPtr
- * in shmem (using SetRedoRecPtr). When checkpointer completes, postmaster
- * calls GetRedoRecPtr to update its own copy of RedoRecPtr, so that
- * subsequently-spawned backends will start out with a reasonably up-to-date
- * local RedoRecPtr. Since these operations are not protected by any lock
- * and copying an XLogRecPtr isn't atomic, it's unsafe to use either of these
- * routines at other times!
- *
- * Note: once spawned, a backend must update its local RedoRecPtr from
- * XLogCtl->Insert.RedoRecPtr while holding the insert lock. This is
- * done in XLogInsert().
+ * in shmem (using SetSavedRedoRecPtr). When checkpointer completes,
+ * postmaster calls GetSavedRedoRecPtr to update its own copy of RedoRecPtr,
+ * so that subsequently-spawned backends will start out with a reasonably
+ * up-to-date local RedoRecPtr. Since these operations are not protected by
+ * any lock and copying an XLogRecPtr isn't atomic, it's unsafe to use either
+ * of these routines at other times!
*/
void
-SetRedoRecPtr(void)
+SetSavedRedoRecPtr(void)
{
- XLogCtl->RedoRecPtr = RedoRecPtr;
+ XLogCtl->SavedRedoRecPtr = RedoRecPtr;
}
void
+GetSavedRedoRecPtr(void)
+{
+ RedoRecPtr = XLogCtl->SavedRedoRecPtr;
+}
+
+/*
+ * Once spawned, a backend may update its local RedoRecPtr from
+ * XLogCtl->Insert.RedoRecPtr; it must hold the insert lock or info_lck
+ * to do so. This is done in XLogInsert() or GetRedoRecPtr().
+ */
+XLogRecPtr
GetRedoRecPtr(void)
{
- RedoRecPtr = XLogCtl->RedoRecPtr;
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
+
+ SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
+ Assert(XLByteLE(RedoRecPtr, xlogctl->Insert.RedoRecPtr));
+ RedoRecPtr = xlogctl->Insert.RedoRecPtr;
+ SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
+
+ return RedoRecPtr;
}
/*
@@ -2862,6 +2890,7 @@ ShutdownXLOG(void)
/* suppress in-transaction check in CreateCheckPoint */
MyLastRecPtr.xrecoff = 0;
+ MyXactMadeXLogEntry = false;
CritSectionCount++;
CreateDummyCaches();
@@ -2886,7 +2915,7 @@ CreateCheckPoint(bool shutdown)
uint32 _logId;
uint32 _logSeg;
- if (MyLastRecPtr.xrecoff != 0)
+ if (MyXactMadeXLogEntry)
elog(ERROR, "CreateCheckPoint: cannot be called inside transaction block");
/*
@@ -2972,9 +3001,16 @@ CreateCheckPoint(bool shutdown)
/*
* Here we update the shared RedoRecPtr for future XLogInsert calls;
- * this must be done while holding the insert lock.
+ * this must be done while holding the insert lock AND the info_lck.
*/
- RedoRecPtr = XLogCtl->Insert.RedoRecPtr = checkPoint.redo;
+ {
+ /* use volatile pointer to prevent code rearrangement */
+ volatile XLogCtlData *xlogctl = XLogCtl;
+
+ SpinLockAcquire_NoHoldoff(&xlogctl->info_lck);
+ RedoRecPtr = xlogctl->Insert.RedoRecPtr = checkPoint.redo;
+ SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
+ }
/*
* Get UNDO record ptr - this is oldest of PROC->logRec values. We do
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 01719a91a676421e8989f02c9311824cb132e800..275b0579ffa8a6ecddf20a8de8ee212cc5d84c48 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.123 2002/03/08 00:42:09 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.124 2002/03/15 19:20:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -386,7 +386,7 @@ BootstrapMain(int argc, char *argv[])
InitDummyProcess(); /* needed to get LWLocks */
CreateDummyCaches();
CreateCheckPoint(false);
- SetRedoRecPtr();
+ SetSavedRedoRecPtr(); /* pass redo ptr back to postmaster */
proc_exit(0); /* done */
case BS_XLOG_STARTUP:
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6b2161a2b17f731638474fef49bf5646734e9f9b..0e57d90dfbcada59ffa86021ada6c00f4203259a 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.70 2002/03/06 06:09:35 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.71 2002/03/15 19:20:35 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -286,6 +286,7 @@ nextval(PG_FUNCTION_ARGS)
char *seqname = get_seq_name(seqin);
SeqTable elm;
Buffer buf;
+ Page page;
Form_pg_sequence seq;
int64 incby,
maxv,
@@ -316,6 +317,7 @@ nextval(PG_FUNCTION_ARGS)
seq = read_info("nextval", elm, &buf); /* lock page' buffer and
* read tuple */
+ page = BufferGetPage(buf);
last = next = result = seq->last_value;
incby = seq->increment_by;
@@ -331,11 +333,33 @@ nextval(PG_FUNCTION_ARGS)
log--;
}
+ /*
+ * Decide whether we should emit a WAL log record. If so, force up
+ * the fetch count to grab SEQ_LOG_VALS more values than we actually
+ * need to cache. (These will then be usable without logging.)
+ *
+ * If this is the first nextval after a checkpoint, we must force
+ * a new WAL record to be written anyway, else replay starting from the
+ * checkpoint would fail to advance the sequence past the logged
+ * values. In this case we may as well fetch extra values.
+ */
if (log < fetch)
{
- fetch = log = fetch - log + SEQ_LOG_VALS;
+ /* forced log to satisfy local demand for values */
+ fetch = log = fetch + SEQ_LOG_VALS;
logit = true;
}
+ else
+ {
+ XLogRecPtr redoptr = GetRedoRecPtr();
+
+ if (XLByteLE(PageGetLSN(page), redoptr))
+ {
+ /* last update of seq was before checkpoint */
+ fetch = log = fetch + SEQ_LOG_VALS;
+ logit = true;
+ }
+ }
while (fetch) /* try to fetch cache [+ log ] numbers */
{
@@ -386,6 +410,9 @@ nextval(PG_FUNCTION_ARGS)
}
}
+ log -= fetch; /* adjust for any unfetched numbers */
+ Assert(log >= 0);
+
/* save info in local cache */
elm->last = result; /* last returned number */
elm->cached = last; /* last fetched number */
@@ -396,7 +423,6 @@ nextval(PG_FUNCTION_ARGS)
xl_seq_rec xlrec;
XLogRecPtr recptr;
XLogRecData rdata[2];
- Page page = BufferGetPage(buf);
xlrec.node = elm->rel->rd_node;
rdata[0].buffer = InvalidBuffer;
@@ -417,15 +443,11 @@ nextval(PG_FUNCTION_ARGS)
PageSetLSN(page, recptr);
PageSetSUI(page, ThisStartUpID);
-
- if (fetch) /* not all numbers were fetched */
- log -= fetch;
}
/* update on-disk data */
seq->last_value = last; /* last fetched number */
seq->is_called = true;
- Assert(log >= 0);
seq->log_cnt = log; /* how much is logged */
END_CRIT_SECTION();
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 02f6d576c60d9465a13286147c7abddc96f83d2e..a6d6097a54c7e39f2a88435a3a07bc99dc880629 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.270 2002/03/04 01:46:03 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.271 2002/03/15 19:20:35 tgl Exp $
*
* NOTES
*
@@ -1683,7 +1683,7 @@ CleanupProc(int pid,
{
checkpointed = time(NULL);
/* Update RedoRecPtr for future child backends */
- GetRedoRecPtr();
+ GetSavedRedoRecPtr();
}
}
else
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 4278f2fbb858ff5960c56da2d84a73db9f945c33..9252a8d324a10968a9f01d6cf362f4a043623c30 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Id: xlog.h,v 1.28 2001/11/05 17:46:31 momjian Exp $
+ * $Id: xlog.h,v 1.29 2002/03/15 19:20:36 tgl Exp $
*/
#ifndef XLOG_H
#define XLOG_H
@@ -178,6 +178,8 @@ typedef struct XLogRecData
extern StartUpID ThisStartUpID; /* current SUI */
extern bool InRecovery;
extern XLogRecPtr MyLastRecPtr;
+extern bool MyXactMadeXLogEntry;
+extern XLogRecPtr ProcLastRecEnd;
/* these variables are GUC parameters related to XLOG */
extern int CheckPointSegments;
@@ -205,8 +207,9 @@ extern void ShutdownXLOG(void);
extern void CreateCheckPoint(bool shutdown);
extern void SetThisStartUpID(void);
extern void XLogPutNextOid(Oid nextOid);
-extern void SetRedoRecPtr(void);
-extern void GetRedoRecPtr(void);
+extern void SetSavedRedoRecPtr(void);
+extern void GetSavedRedoRecPtr(void);
+extern XLogRecPtr GetRedoRecPtr(void);
/* in storage/ipc/sinval.c, but don't want to declare in sinval.h because
* we'd have to include xlog.h into that ...