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| author | Simon Riggs <simon@2ndQuadrant.com> | 2012-05-11 14:38:11 +0100 |
|---|---|---|
| committer | Simon Riggs <simon@2ndQuadrant.com> | 2012-05-11 14:38:11 +0100 |
| commit | 1a4bc2db6cb80a6e52aed8f5a68b895231653d6c (patch) | |
| tree | 2882f193163ac3fac7c582f1bb9fcc1498219d88 /src/backend/access/transam/xact.c | |
| parent | 153b1dbaa0b94143041ab1e0cf249a02380f0acf (diff) | |
| download | postgresql-1a4bc2db6cb80a6e52aed8f5a68b895231653d6c.tar.gz postgresql-1a4bc2db6cb80a6e52aed8f5a68b895231653d6c.zip | |
Ensure age() returns a stable value rather than the latest value
Diffstat (limited to 'src/backend/access/transam/xact.c')
| -rw-r--r-- | src/backend/access/transam/xact.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 901fff059a1..be4905181e0 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -394,6 +394,28 @@ GetCurrentTransactionIdIfAny(void) /* + * GetStableLatestTransactionIdIfAny + * + * Get the latest XID once and then return same value for rest of transaction. + * Acts as a useful reference point for maintenance tasks. + */ +TransactionId +GetStableLatestTransactionId(void) +{ + static LocalTransactionId lxid = InvalidLocalTransactionId; + static TransactionId stablexid = InvalidTransactionId; + + if (lxid != MyProc->lxid || + !TransactionIdIsValid(stablexid)) + { + lxid = MyProc->lxid; + stablexid = ReadNewTransactionId(); + } + + return stablexid; +} + +/* * AssignTransactionId * * Assigns a new permanent XID to the given TransactionState. |