diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 411807006ac..2b579f9b727 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -6884,8 +6884,8 @@ CreateCheckPoint(int flags) XLogRecData rdata; uint32 freespace; XLogSegNo _logSegNo; - TransactionId *inCommitXids; - int nInCommit; + VirtualTransactionId *vxids; + int nvxids; /* * An end-of-recovery checkpoint is really a shutdown checkpoint, just @@ -7056,9 +7056,14 @@ CreateCheckPoint(int flags) TRACE_POSTGRESQL_CHECKPOINT_START(flags); /* - * Before flushing data, we must wait for any transactions that are - * currently in their commit critical sections. If an xact inserted its - * commit record into XLOG just before the REDO point, then a crash + * In some cases there are groups of actions that must all occur on + * one side or the other of a checkpoint record. Before flushing the + * checkpoint record we must explicitly wait for any backend currently + * performing those groups of actions. + * + * One example is end of transaction, so we must wait for any transactions + * that are currently in commit critical sections. If an xact inserted + * its commit record into XLOG just before the REDO point, then a crash * restart from the REDO point would not replay that record, which means * that our flushing had better include the xact's update of pg_clog. So * we wait till he's out of his commit critical section before proceeding. @@ -7073,21 +7078,24 @@ CreateCheckPoint(int flags) * protected by different locks, but again that seems best on grounds of * minimizing lock contention.) * - * A transaction that has not yet set inCommit when we look cannot be at + * A transaction that has not yet set delayChkpt when we look cannot be at * risk, since he's not inserted his commit record yet; and one that's * already cleared it is not at risk either, since he's done fixing clog * and we will correctly flush the update below. So we cannot miss any * xacts we need to wait for. */ - nInCommit = GetTransactionsInCommit(&inCommitXids); - if (nInCommit > 0) + vxids = GetVirtualXIDsDelayingChkpt(&nvxids); + if (nvxids > 0) { + uint nwaits = 0; + do { pg_usleep(10000L); /* wait for 10 msec */ - } while (HaveTransactionsInCommit(inCommitXids, nInCommit)); + nwaits++; + } while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids)); } - pfree(inCommitXids); + pfree(vxids); /* * Get the other info we need for the checkpoint record. |