From b71a67d21df2028396a533097d74a828ed421f3f Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Mon, 1 Nov 2021 14:39:36 -0400 Subject: [PATCH 11/11] Demote ThisTimeLineID to a local variable. Instead of a file-level global variable, it can now be made local to StartupXLOG. The only other code that still accesses it is in BootstrapXLOG, where we now just use a constant instead. --- src/backend/access/transam/xlog.c | 35 ++++++++++--------------------- 1 file changed, 11 insertions(+), 24 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 8a650b875e..dcc215dcc2 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -88,6 +88,9 @@ extern uint32 bootstrap_data_checksum_version; #define RECOVERY_COMMAND_FILE "recovery.conf" #define RECOVERY_COMMAND_DONE "recovery.done" +/* timeline ID to be used when bootstrapping */ +#define BootstrapTimeLineID 1 + /* User-settable parameters */ int max_wal_size_mb = 1024; /* 1 GB */ int min_wal_size_mb = 80; /* 80 MB */ @@ -188,12 +191,6 @@ const struct config_enum_entry recovery_target_action_options[] = { */ CheckpointStatsData CheckpointStats; -/* - * ThisTimeLineID will be same in all backends --- it identifies current - * WAL timeline for the database system. - */ -static TimeLineID ThisTimeLineID = 0; - static XLogRecPtr LastRec; /* Local copy of WalRcv->flushedUpto */ @@ -5368,9 +5365,6 @@ BootStrapXLOG(void) sysidentifier |= ((uint64) tv.tv_usec) << 12; sysidentifier |= getpid() & 0xFFF; - /* First timeline ID is always 1 */ - ThisTimeLineID = 1; - /* page buffer must be aligned suitably for O_DIRECT */ buffer = (char *) palloc(XLOG_BLCKSZ + XLOG_BLCKSZ); page = (XLogPageHeader) TYPEALIGN(XLOG_BLCKSZ, buffer); @@ -5384,8 +5378,8 @@ BootStrapXLOG(void) * used, so that we can use 0/0 to mean "before any valid WAL segment". */ checkPoint.redo = wal_segment_size + SizeOfXLogLongPHD; - checkPoint.ThisTimeLineID = ThisTimeLineID; - checkPoint.PrevTimeLineID = ThisTimeLineID; + checkPoint.ThisTimeLineID = BootstrapTimeLineID; + checkPoint.PrevTimeLineID = BootstrapTimeLineID; checkPoint.fullPageWrites = fullPageWrites; checkPoint.nextXid = FullTransactionIdFromEpochAndXid(0, FirstNormalTransactionId); @@ -5413,7 +5407,7 @@ BootStrapXLOG(void) /* Set up the XLOG page header */ page->xlp_magic = XLOG_PAGE_MAGIC; page->xlp_info = XLP_LONG_HEADER; - page->xlp_tli = ThisTimeLineID; + page->xlp_tli = BootstrapTimeLineID; page->xlp_pageaddr = wal_segment_size; longpage = (XLogLongPageHeader) page; longpage->xlp_sysid = sysidentifier; @@ -5443,8 +5437,8 @@ BootStrapXLOG(void) record->xl_crc = crc; /* Create first XLOG segment file */ - openLogTLI = ThisTimeLineID; - openLogFile = XLogFileInit(1, ThisTimeLineID); + openLogTLI = BootstrapTimeLineID; + openLogFile = XLogFileInit(1, BootstrapTimeLineID); /* * We needn't bother with Reserve/ReleaseExternalFD here, since we'll @@ -6681,7 +6675,8 @@ StartupXLOG(void) checkPointLoc, EndOfLog; TimeLineID EndOfLogTLI; - TimeLineID PrevTimeLineID; + TimeLineID ThisTimeLineID, + PrevTimeLineID; XLogRecord *record; TransactionId oldestActiveXID; bool backupEndRequired = false; @@ -8661,21 +8656,13 @@ ReadCheckpointRecord(XLogReaderState *xlogreader, XLogRecPtr RecPtr, /* * This must be called in a backend process before creating WAL records * (except in a standalone backend, which does StartupXLOG instead). We need - * to initialize the local copies of ThisTimeLineID and RedoRecPtr. - * - * Note: before Postgres 8.0, we went to some effort to keep the postmaster - * process's copies of ThisTimeLineID and RedoRecPtr valid too. This was - * unnecessary however, since the postmaster itself never touches XLOG anyway. + * to initialize the local copy of RedoRecPtr. */ void InitXLOGAccess(void) { XLogCtlInsert *Insert = &XLogCtl->Insert; - /* ThisTimeLineID doesn't change so we need no lock to copy it */ - ThisTimeLineID = XLogCtl->ThisTimeLineID; - Assert(ThisTimeLineID != 0 || IsBootstrapProcessingMode()); - /* set wal_segment_size */ wal_segment_size = ControlFile->xlog_seg_size; -- 2.24.3 (Apple Git-128)