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Ensure age() returns a stable value rather than the latest value

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Simon Riggs
2012-05-11 14:36:24 +01:00
parent 3652d72dd4
commit b06679e012
3 changed files with 26 additions and 5 deletions
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22
src/backend/access/transam/xact.c
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@ -391,6 +391,28 @@ 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
*