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Two-phase commit. Original patch by Heikki Linnakangas, with additional
hacking by Alvaro Herrera and Tom Lane.
This commit is contained in:
Tom Lane
@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.200 2005/06/15 01:36:08 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.201 2005/06/17 22:32:43 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -25,6 +25,7 @@
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#include "access/clog.h"
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#include "access/multixact.h"
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#include "access/subtrans.h"
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#include "access/twophase.h"
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#include "access/xact.h"
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#include "access/xlog.h"
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#include "access/xlog_internal.h"
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@ -814,18 +815,6 @@ begin:;
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/* Compute record's XLOG location */
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INSERT_RECPTR(RecPtr, Insert, curridx);
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/* If first XLOG record of transaction, save it in PGPROC array */
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if (MyLastRecPtr.xrecoff == 0 && !no_tran)
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{
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/*
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* We do not acquire ProcArrayLock here because of possible deadlock.
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* Anyone who wants to inspect other procs' logRec must acquire
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* WALInsertLock, instead. A better solution would be a per-PROC
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* spinlock, but no time for that before 7.2 --- tgl 12/19/01.
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*/
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MyProc->logRec = RecPtr;
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}
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#ifdef WAL_DEBUG
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if (XLOG_DEBUG)
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{
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@ -3827,6 +3816,7 @@ BootStrapXLOG(void)
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BootStrapCLOG();
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BootStrapSUBTRANS();
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BootStrapMultiXact();
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free(buffer);
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}
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@ -4268,6 +4258,7 @@ StartupXLOG(void)
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uint32 endLogSeg;
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XLogRecord *record;
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uint32 freespace;
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TransactionId oldestActiveXID;
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CritSectionCount++;
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@ -4678,33 +4669,8 @@ StartupXLOG(void)
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XLogCtl->Write.curridx = NextBufIdx(0);
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}
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#ifdef NOT_USED
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/* UNDO */
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if (InRecovery)
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{
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RecPtr = ReadRecPtr;
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if (XLByteLT(checkPoint.undo, RecPtr))
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{
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ereport(LOG,
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(errmsg("undo starts at %X/%X",
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RecPtr.xlogid, RecPtr.xrecoff)));
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do
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{
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record = ReadRecord(&RecPtr, PANIC);
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if (TransactionIdIsValid(record->xl_xid) &&
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!TransactionIdDidCommit(record->xl_xid))
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RmgrTable[record->xl_rmid].rm_undo(EndRecPtr, record);
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RecPtr = record->xl_prev;
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} while (XLByteLE(checkPoint.undo, RecPtr));
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ereport(LOG,
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(errmsg("undo done at %X/%X",
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ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
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}
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else
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ereport(LOG,
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(errmsg("undo is not required")));
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}
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#endif
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/* Pre-scan prepared transactions to find out the range of XIDs present */
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oldestActiveXID = PrescanPreparedTransactions();
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if (InRecovery)
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{
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@ -4767,9 +4733,12 @@ StartupXLOG(void)
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/* Start up the commit log and related stuff, too */
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StartupCLOG();
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StartupSUBTRANS();
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StartupSUBTRANS(oldestActiveXID);
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StartupMultiXact();
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/* Reload shared-memory state for prepared transactions */
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RecoverPreparedTransactions();
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ereport(LOG,
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(errmsg("database system is ready")));
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CritSectionCount--;
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@ -5095,31 +5064,6 @@ CreateCheckPoint(bool shutdown, bool force)
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SpinLockRelease_NoHoldoff(&xlogctl->info_lck);
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}
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/*
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* Get UNDO record ptr - this is oldest of PGPROC->logRec values. We
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* do this while holding insert lock to ensure that we won't miss any
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* about-to-commit transactions (UNDO must include all xacts that have
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* commits after REDO point).
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*
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* XXX temporarily ifdef'd out to avoid three-way deadlock condition:
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* GetUndoRecPtr needs to grab ProcArrayLock to ensure that it is looking
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* at a stable set of proc records, but grabbing ProcArrayLock while
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* holding WALInsertLock is no good. GetNewTransactionId may cause a
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* WAL record to be written while holding XidGenLock, and
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* GetSnapshotData needs to get XidGenLock while holding ProcArrayLock,
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* so there's a risk of deadlock. Need to find a better solution. See
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* pgsql-hackers discussion of 17-Dec-01.
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*
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* XXX actually, the whole UNDO code is dead code and unlikely to ever be
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* revived, so the lack of a good solution here is not troubling.
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*/
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#ifdef NOT_USED
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checkPoint.undo = GetUndoRecPtr();
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if (shutdown && checkPoint.undo.xrecoff != 0)
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elog(PANIC, "active transaction while database system is shutting down");
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#endif
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/*
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* Now we can release insert lock and checkpoint start lock, allowing
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* other xacts to proceed even while we are flushing disk buffers.
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@ -5195,22 +5139,8 @@ CreateCheckPoint(bool shutdown, bool force)
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/*
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* Select point at which we can truncate the log, which we base on the
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* prior checkpoint's earliest info.
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*
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* With UNDO support: oldest item is redo or undo, whichever is older;
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* but watch out for case that undo = 0.
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*
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* Without UNDO support: just use the redo pointer. This allows xlog
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* space to be freed much faster when there are long-running
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* transactions.
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*/
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#ifdef NOT_USED
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if (ControlFile->checkPointCopy.undo.xrecoff != 0 &&
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XLByteLT(ControlFile->checkPointCopy.undo,
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ControlFile->checkPointCopy.redo))
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XLByteToSeg(ControlFile->checkPointCopy.undo, _logId, _logSeg);
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else
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#endif
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XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg);
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XLByteToSeg(ControlFile->checkPointCopy.redo, _logId, _logSeg);
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/*
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* Update the control file.
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