diff options
Diffstat (limited to 'src/backend/access/transam/twophase.c')
| -rw-r--r-- | src/backend/access/transam/twophase.c | 26 |
1 files changed, 5 insertions, 21 deletions
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index ab2f4a8a92f..73a80559194 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -929,32 +929,16 @@ TwoPhaseGetDummyProc(TransactionId xid, bool lock_held) /* * Compute the FullTransactionId for the given TransactionId. * - * The wrap logic is safe here because the span of active xids cannot exceed one - * epoch at any given time. + * This is safe if the xid has not yet reached COMMIT PREPARED or ROLLBACK + * PREPARED. After those commands, concurrent vac_truncate_clog() may make + * the xid cease to qualify as allowable. XXX Not all callers limit their + * calls accordingly. */ static inline FullTransactionId AdjustToFullTransactionId(TransactionId xid) { - FullTransactionId nextFullXid; - TransactionId nextXid; - uint32 epoch; - Assert(TransactionIdIsValid(xid)); - - LWLockAcquire(XidGenLock, LW_SHARED); - nextFullXid = TransamVariables->nextXid; - LWLockRelease(XidGenLock); - - nextXid = XidFromFullTransactionId(nextFullXid); - epoch = EpochFromFullTransactionId(nextFullXid); - if (unlikely(xid > nextXid)) - { - /* Wraparound occurred, must be from a prev epoch. */ - Assert(epoch > 0); - epoch--; - } - - return FullTransactionIdFromEpochAndXid(epoch, xid); + return FullTransactionIdFromAllowableAt(ReadNextFullTransactionId(), xid); } static inline int |