From e6ddbe87d598c6a1090e39845a4a308060f0af1e Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 3 Apr 2024 11:23:12 +0200 Subject: [PATCH v15 1/3] split XLogCtl->LogwrtResult into separate struct members --- src/backend/access/transam/xlog.c | 59 ++++++++++++++++++------------- 1 file changed, 35 insertions(+), 24 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 87ea03954b..6213d99561 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -291,16 +291,15 @@ static bool doPageWrites; * * LogwrtRqst indicates a byte position that we need to write and/or fsync * the log up to (all records before that point must be written or fsynced). - * LogwrtResult indicates the byte positions we have already written/fsynced. - * These structs are identical but are declared separately to indicate their - * slightly different functions. + * The positions already written/fsynced are maintained in logWriteResult + * and logFlushResult. * - * To read XLogCtl->LogwrtResult, you must hold either info_lck or - * WALWriteLock. To update it, you need to hold both locks. The point of - * this arrangement is that the value can be examined by code that already - * holds WALWriteLock without needing to grab info_lck as well. In addition - * to the shared variable, each backend has a private copy of LogwrtResult, - * which is updated when convenient. + * To read XLogCtl->logWriteResult or ->logFlushResult, you must hold either + * info_lck or WALWriteLock. To update them, you need to hold both locks. + * The point of this arrangement is that the value can be examined by code + * that already holds WALWriteLock without needing to grab info_lck as well. + * In addition to the shared variable, each backend has a private copy of + * both in LogwrtResult, which is updated when convenient. * * The request bookkeeping is simpler: there is a shared XLogCtl->LogwrtRqst * (protected by info_lck), but we don't need to cache any copies of it. @@ -478,7 +477,8 @@ typedef struct XLogCtlData * Protected by info_lck and WALWriteLock (you must hold either lock to * read it, but both to update) */ - XLogwrtResult LogwrtResult; + XLogRecPtr logWriteResult; /* last byte + 1 written out */ + XLogRecPtr logFlushResult; /* last byte + 1 flushed */ /* * Latest initialized page in the cache (last byte position + 1). @@ -614,6 +614,15 @@ static int UsableBytesInSegment; */ static XLogwrtResult LogwrtResult = {0, 0}; +/* + * Update local copy of shared XLogCtl->log{Write,Flush}Result + */ +#define XLogUpdateLocalLogwrtResult(_target) \ + do { \ + _target.Write = XLogCtl->logWriteResult; \ + _target.Flush = XLogCtl->logFlushResult; \ + } while (0) + /* * openLogFile is -1 or a kernel FD for an open log file segment. * openLogSegNo identifies the segment, and openLogTLI the corresponding TLI. @@ -960,7 +969,7 @@ XLogInsertRecord(XLogRecData *rdata, if (XLogCtl->LogwrtRqst.Write < EndPos) XLogCtl->LogwrtRqst.Write = EndPos; /* update local result copy while I have the chance */ - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); } @@ -1984,7 +1993,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, TimeLineID tli, bool opportunistic) SpinLockAcquire(&XLogCtl->info_lck); if (XLogCtl->LogwrtRqst.Write < OldPageRqstPtr) XLogCtl->LogwrtRqst.Write = OldPageRqstPtr; - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); /* @@ -2005,7 +2014,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, TimeLineID tli, bool opportunistic) LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); if (LogwrtResult.Write >= OldPageRqstPtr) { /* OK, someone wrote it already */ @@ -2289,7 +2298,7 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible) /* * Update local LogwrtResult (caller probably did this already, but...) */ - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); /* * Since successive pages in the xlog cache are consecutively allocated, @@ -2549,7 +2558,8 @@ XLogWrite(XLogwrtRqst WriteRqst, TimeLineID tli, bool flexible) */ { SpinLockAcquire(&XLogCtl->info_lck); - XLogCtl->LogwrtResult = LogwrtResult; + XLogCtl->logWriteResult = LogwrtResult.Write; + XLogCtl->logFlushResult = LogwrtResult.Flush; if (XLogCtl->LogwrtRqst.Write < LogwrtResult.Write) XLogCtl->LogwrtRqst.Write = LogwrtResult.Write; if (XLogCtl->LogwrtRqst.Flush < LogwrtResult.Flush) @@ -2572,7 +2582,7 @@ XLogSetAsyncXactLSN(XLogRecPtr asyncXactLSN) XLogRecPtr prevAsyncXactLSN; SpinLockAcquire(&XLogCtl->info_lck); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); sleeping = XLogCtl->WalWriterSleeping; prevAsyncXactLSN = XLogCtl->asyncXactLSN; if (XLogCtl->asyncXactLSN < asyncXactLSN) @@ -2784,7 +2794,7 @@ XLogFlush(XLogRecPtr record) SpinLockAcquire(&XLogCtl->info_lck); if (WriteRqstPtr < XLogCtl->LogwrtRqst.Write) WriteRqstPtr = XLogCtl->LogwrtRqst.Write; - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); /* done already? */ @@ -2815,7 +2825,7 @@ XLogFlush(XLogRecPtr record) } /* Got the lock; recheck whether request is satisfied */ - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); if (record <= LogwrtResult.Flush) { LWLockRelease(WALWriteLock); @@ -2939,7 +2949,7 @@ XLogBackgroundFlush(void) /* read LogwrtResult and update local state */ SpinLockAcquire(&XLogCtl->info_lck); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); WriteRqst = XLogCtl->LogwrtRqst; SpinLockRelease(&XLogCtl->info_lck); @@ -3027,7 +3037,7 @@ XLogBackgroundFlush(void) /* now wait for any in-progress insertions to finish and get write lock */ WaitXLogInsertionsToFinish(WriteRqst.Write); LWLockAcquire(WALWriteLock, LW_EXCLUSIVE); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); if (WriteRqst.Write > LogwrtResult.Write || WriteRqst.Flush > LogwrtResult.Flush) { @@ -3116,7 +3126,7 @@ XLogNeedsFlush(XLogRecPtr record) /* read LogwrtResult and update local state */ SpinLockAcquire(&XLogCtl->info_lck); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); /* check again */ @@ -5953,7 +5963,8 @@ StartupXLOG(void) LogwrtResult.Write = LogwrtResult.Flush = EndOfLog; - XLogCtl->LogwrtResult = LogwrtResult; + XLogCtl->logWriteResult = LogwrtResult.Write; + XLogCtl->logFlushResult = LogwrtResult.Flush; XLogCtl->LogwrtRqst.Write = EndOfLog; XLogCtl->LogwrtRqst.Flush = EndOfLog; @@ -6400,7 +6411,7 @@ GetFlushRecPtr(TimeLineID *insertTLI) Assert(XLogCtl->SharedRecoveryState == RECOVERY_STATE_DONE); SpinLockAcquire(&XLogCtl->info_lck); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); /* @@ -9316,7 +9327,7 @@ XLogRecPtr GetXLogWriteRecPtr(void) { SpinLockAcquire(&XLogCtl->info_lck); - LogwrtResult = XLogCtl->LogwrtResult; + XLogUpdateLocalLogwrtResult(LogwrtResult); SpinLockRelease(&XLogCtl->info_lck); return LogwrtResult.Write; -- 2.39.2