Re: HOT is applied

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 18:29:05
Message-ID: 14662.1190399345@sss.pgh.pa.us
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"Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> writes:
> We've already checked that the xmin is our own transaction id, so we
> check if the xmax is an aborted subtransaction of our own transaction. A
> TransactionIdDidAbort call seems like an awfully expensive way to check
> that. We could call TransactionIdIsCurrentTransactionId instead, which
> doesn't need to access any shared memory structures (but might be
> expensive if you have a lot of active subxacts, as you pointed out).

Applied --- seems to buy another 50% savings in the example with all the
pruning activity. I'll get after the pruning activity itself in a bit,
but it seems worth squeezing the tqual functions first while we have
this example that stresses them so much.

regards, tom lane

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