From 976679bc590560d3c051e30e7576e7d3d03070e6 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Wed, 12 Oct 2022 14:43:41 -0700 Subject: [PATCH v5 1/3] Have GetCurrentTransactionStopTimestamp() set xactStopTimestamp if unset Previously GetCurrentTransactionStopTimestamp() computed a new timestamp whenever xactStopTimestamp was unset and xactStopTimestamp was only set when a commit or abort record was written. An upcoming patch will add additional calls to GetCurrentTransactionStopTimestamp() from pgstats. To avoid computing timestamps multiple times, set xactStopTimestamp in GetCurrentTransactionStopTimestamp() if not already set. Author: Dave Page Reviewed-by: Andres Freund Reviewed-by: Vik Fearing Discussion: https://postgr.es/m/20220906155325.an3xesq5o3fq36gt%40awork3.anarazel.de --- src/backend/access/transam/xact.c | 42 +++++++++++++++---------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index c1ffbd89b88..fd5103a78e2 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -263,7 +263,10 @@ static bool currentCommandIdUsed; /* * xactStartTimestamp is the value of transaction_timestamp(). * stmtStartTimestamp is the value of statement_timestamp(). - * xactStopTimestamp is the time at which we log a commit or abort WAL record. + * xactStopTimestamp is the time at which we log a commit / abort WAL record, + * or if that was skipped, the time of the first subsequent + * GetCurrentTransactionStopTimestamp() call. + * * These do not change as we enter and exit subtransactions, so we don't * keep them inside the TransactionState stack. */ @@ -865,15 +868,24 @@ GetCurrentStatementStartTimestamp(void) /* * GetCurrentTransactionStopTimestamp * - * We return current time if the transaction stop time hasn't been set - * (which can happen if we decide we don't need to log an XLOG record). + * If the transaction stop time hasn't already been set, which can happen if + * we decided we don't need to log an XLOG record, set xactStopTimestamp. */ TimestampTz GetCurrentTransactionStopTimestamp(void) { - if (xactStopTimestamp != 0) - return xactStopTimestamp; - return GetCurrentTimestamp(); + TransactionState s PG_USED_FOR_ASSERTS_ONLY = CurrentTransactionState; + + /* should only be called after commit / abort processing */ + Assert(s->state == TRANS_DEFAULT || + s->state == TRANS_COMMIT || + s->state == TRANS_ABORT || + s->state == TRANS_PREPARE); + + if (xactStopTimestamp == 0) + xactStopTimestamp = GetCurrentTimestamp(); + + return xactStopTimestamp; } /* @@ -891,15 +903,6 @@ SetCurrentStatementStartTimestamp(void) Assert(stmtStartTimestamp != 0); } -/* - * SetCurrentTransactionStopTimestamp - */ -static inline void -SetCurrentTransactionStopTimestamp(void) -{ - xactStopTimestamp = GetCurrentTimestamp(); -} - /* * GetCurrentTransactionNestLevel * @@ -1396,9 +1399,7 @@ RecordTransactionCommit(void) START_CRIT_SECTION(); MyProc->delayChkptFlags |= DELAY_CHKPT_START; - SetCurrentTransactionStopTimestamp(); - - XactLogCommitRecord(xactStopTimestamp, + XactLogCommitRecord(GetCurrentTransactionStopTimestamp(), nchildren, children, nrels, rels, ndroppedstats, droppedstats, nmsgs, invalMessages, @@ -1422,7 +1423,7 @@ RecordTransactionCommit(void) */ if (!replorigin || replorigin_session_origin_timestamp == 0) - replorigin_session_origin_timestamp = xactStopTimestamp; + replorigin_session_origin_timestamp = GetCurrentTransactionStopTimestamp(); TransactionTreeSetCommitTsData(xid, nchildren, children, replorigin_session_origin_timestamp, @@ -1754,8 +1755,7 @@ RecordTransactionAbort(bool isSubXact) xact_time = GetCurrentTimestamp(); else { - SetCurrentTransactionStopTimestamp(); - xact_time = xactStopTimestamp; + xact_time = GetCurrentTransactionStopTimestamp(); } XactLogAbortRecord(xact_time, -- 2.38.0