diff options
Diffstat (limited to 'src/backend/access/transam/xlogreader.c')
| -rw-r--r-- | src/backend/access/transam/xlogreader.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 41dae916b46..33ccfc15531 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -26,6 +26,7 @@ #include "replication/origin.h" #ifndef FRONTEND +#include "miscadmin.h" #include "utils/memutils.h" #endif @@ -1443,3 +1444,37 @@ RestoreBlockImage(XLogReaderState *record, uint8 block_id, char *page) return true; } + +#ifndef FRONTEND + +/* + * Extract the FullTransactionId from a WAL record. + */ +FullTransactionId +XLogRecGetFullXid(XLogReaderState *record) +{ + TransactionId xid, + next_xid; + uint32 epoch; + + /* + * This function is only safe during replay, because it depends on the + * replay state. See AdvanceNextFullTransactionIdPastXid() for more. + */ + Assert(AmStartupProcess() || !IsUnderPostmaster); + + xid = XLogRecGetXid(record); + next_xid = XidFromFullTransactionId(ShmemVariableCache->nextFullXid); + epoch = EpochFromFullTransactionId(ShmemVariableCache->nextFullXid); + + /* + * If xid is numerically greater than next_xid, it has to be from the + * last epoch. + */ + if (unlikely(xid > next_xid)) + --epoch; + + return FullTransactionIdFromEpochAndXid(epoch, xid); +}; + +#endif |