diff options
Diffstat (limited to 'src/backend/access/transam/twophase.c')
| -rw-r--r-- | src/backend/access/transam/twophase.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index 85cbe397cb2..7918176fc58 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1183,7 +1183,11 @@ EndPrepare(GlobalTransaction gxact) * starting immediately after the WAL record is inserted could complete * without fsync'ing our state file. (This is essentially the same kind * of race condition as the COMMIT-to-clog-write case that - * RecordTransactionCommit uses DELAY_CHKPT_START for; see notes there.) + * RecordTransactionCommit uses DELAY_CHKPT_IN_COMMIT for; see notes + * there.) Note that DELAY_CHKPT_IN_COMMIT is used to find transactions in + * the critical commit section. We need to know about such transactions + * for conflict detection in logical replication. See + * GetOldestActiveTransactionId(true, false) and its use. * * We save the PREPARE record's location in the gxact for later use by * CheckPointTwoPhase. @@ -2298,7 +2302,7 @@ ProcessTwoPhaseBuffer(FullTransactionId fxid, * RecordTransactionCommitPrepared * * This is basically the same as RecordTransactionCommit (q.v. if you change - * this function): in particular, we must set DELAY_CHKPT_START to avoid a + * this function): in particular, we must set DELAY_CHKPT_IN_COMMIT to avoid a * race condition. * * We know the transaction made at least one XLOG entry (its PREPARE), @@ -2318,7 +2322,7 @@ RecordTransactionCommitPrepared(TransactionId xid, const char *gid) { XLogRecPtr recptr; - TimestampTz committs = GetCurrentTimestamp(); + TimestampTz committs; bool replorigin; /* @@ -2331,8 +2335,24 @@ RecordTransactionCommitPrepared(TransactionId xid, START_CRIT_SECTION(); /* See notes in RecordTransactionCommit */ - Assert((MyProc->delayChkptFlags & DELAY_CHKPT_START) == 0); - MyProc->delayChkptFlags |= DELAY_CHKPT_START; + Assert((MyProc->delayChkptFlags & DELAY_CHKPT_IN_COMMIT) == 0); + MyProc->delayChkptFlags |= DELAY_CHKPT_IN_COMMIT; + + /* + * Ensures the DELAY_CHKPT_IN_COMMIT flag write is globally visible before + * commit time is written. + */ + pg_write_barrier(); + + /* + * Note it is important to set committs value after marking ourselves as + * in the commit critical section (DELAY_CHKPT_IN_COMMIT). This is because + * we want to ensure all transactions that have acquired commit timestamp + * are finished before we allow the logical replication client to advance + * its xid which is used to hold back dead rows for conflict detection. + * See comments atop worker.c. + */ + committs = GetCurrentTimestamp(); /* * Emit the XLOG commit record. Note that we mark 2PC commits as @@ -2381,7 +2401,7 @@ RecordTransactionCommitPrepared(TransactionId xid, TransactionIdCommitTree(xid, nchildren, children); /* Checkpoint can proceed now */ - MyProc->delayChkptFlags &= ~DELAY_CHKPT_START; + MyProc->delayChkptFlags &= ~DELAY_CHKPT_IN_COMMIT; END_CRIT_SECTION(); |