diff options
Diffstat (limited to 'src/backend/storage/ipc/procarray.c')
| -rw-r--r-- | src/backend/storage/ipc/procarray.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 8eaec0ca6ed..68cc6edd092 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -1683,6 +1683,50 @@ ProcArrayInstallImportedXmin(TransactionId xmin, TransactionId sourcexid) } /* + * ProcArrayInstallRestoredXmin -- install restored xmin into MyPgXact->xmin + * + * This is like ProcArrayInstallImportedXmin, but we have a pointer to the + * PGPROC of the transaction from which we imported the snapshot, rather than + * an XID. + * + * Returns TRUE if successful, FALSE if source xact is no longer running. + */ +bool +ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc) +{ + bool result = false; + TransactionId xid; + volatile PGXACT *pgxact; + + Assert(TransactionIdIsNormal(xmin)); + Assert(proc != NULL); + + /* Get lock so source xact can't end while we're doing this */ + LWLockAcquire(ProcArrayLock, LW_SHARED); + + pgxact = &allPgXact[proc->pgprocno]; + + /* + * Be certain that the referenced PGPROC has an advertised xmin which + * is no later than the one we're installing, so that the system-wide + * xmin can't go backwards. Also, make sure it's running in the same + * database, so that the per-database xmin cannot go backwards. + */ + xid = pgxact->xmin; /* fetch just once */ + if (proc->databaseId == MyDatabaseId && + TransactionIdIsNormal(xid) && + TransactionIdPrecedesOrEquals(xid, xmin)) + { + MyPgXact->xmin = TransactionXmin = xmin; + result = true; + } + + LWLockRelease(ProcArrayLock); + + return result; +} + +/* * GetRunningTransactionData -- returns information about running transactions. * * Similar to GetSnapshotData but returns more information. We include |