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| author | Thomas Munro <tmunro@postgresql.org> | 2019-11-11 16:33:04 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2019-11-11 16:33:04 +1300 |
| commit | 695c5977c8bc115029a85dcc1821d7b0136b4e4c (patch) | |
| tree | 61b9edb5b40e3eb4afeec44a34d7a630894ca091 | |
| parent | 9fab25c6cd1f943284b8e0014007cd5750d54308 (diff) | |
| download | postgresql-695c5977c8bc115029a85dcc1821d7b0136b4e4c.tar.gz postgresql-695c5977c8bc115029a85dcc1821d7b0136b4e4c.zip | |
Optimize TransactionIdIsCurrentTransactionId().
If the passed in xid is the current top transaction, we can do a fast
check and exit early. This should work well for the current heap but
also works very well for proposed AMs that don't use a separate xid
for subtransactions.
Author: Ashwin Agrawal, based on a suggestion from Andres Freund
Reviewed-by: Thomas Munro
Discussion: https://postgr.es/m/CALfoeiv0k3hkEb3Oqk%3DziWqtyk2Jys1UOK5hwRBNeANT_yX%2Bng%40mail.gmail.com
| -rw-r--r-- | src/backend/access/transam/xact.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index fc55fa6d53c..e5e2902465a 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -871,6 +871,9 @@ TransactionIdIsCurrentTransactionId(TransactionId xid) if (!TransactionIdIsNormal(xid)) return false; + if (TransactionIdEquals(xid, GetTopTransactionIdIfAny())) + return true; + /* * In parallel workers, the XIDs we must consider as current are stored in * ParallelCurrentXids rather than the transaction-state stack. Note that |