From: jesper@krogh.cc
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kevin Grittner <kgrittn@ymail.com>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: Bartłomiej Romański <br@sentia.pl>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Planner performance extremely affected by an hanging transaction (20-30 times)?
Date: Tue, 24 Sep 2013 17:01:14 +0200 (CEST)
Message-ID: <e8795f5e292a0bd1a4d8ebbcb54e4a98.squirrel@shrek.krogh.cc> (raw)
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> Kevin Grittner <kgrittn@ymail.com> writes:
>> Are we talking about the probe for the end (or beginning) of an
>> index? If so, should we even care about visibility of the row
>> related to the most extreme index entry? Should we even go to the
>> heap during the plan phase?
>
> Consider the case where some transaction inserted a wildly out-of-range
> value, then rolled back. If we don't check validity of the heap row,
> we'd be using that silly endpoint value for planning purposes ---
> indefinitely. That's not an improvement over the situation that the
> probe is meant to fix.
Apparently it is waiting for locks, cant the check be make in a
"non-blocking" way, so if it ends up waiting for a lock then it just
assumes non-visible and moves onto the next non-blocking?
This stuff is a 9.2 feature right? What was the original problem to be
adressed?
--
Jesper
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Cc: jesper@krogh.cc, tgl@sss.pgh.pa.us, kgrittn@ymail.com, jeff.janes@gmail.com, br@sentia.pl
Subject: Re: Planner performance extremely affected by an hanging transaction (20-30 times)?
In-Reply-To: <e8795f5e292a0bd1a4d8ebbcb54e4a98.squirrel@shrek.krogh.cc>
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