| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> |
| Cc: | "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: HOT is applied |
| Date: | 2007-09-21 19:00:22 |
| Message-ID: | 15120.1190401222@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
"Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> writes:
> I noted that most callers of TransactionIdIsInProgress in tqual.c
> already call TransactionIdIsCurrentTransactionId before
> TransactionIdIsInProgress. In those cases we could just skip the test
> for our own xids altogether, if it's worth code mangling to tell
> TransactionIdIsInProgress whether it's safe to skip it or not.
At least in this example, it seems it wouldn't buy anything.
HeapTupleSatisfiesVacuum doesn't call
TransactionIdIsCurrentTransactionId, and while HeapTupleSatisfiesMVCC
does, it falls out at that point and doesn't get to
TransactionIdIsInProgress. So I'm not inclined to contort the API
unless we can come up with an example where it's important.
I'm off to work on the page-header-xid idea ...
regards, tom lane
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