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Re: HOT Patch - Ready for review

From: "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com>
To: "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: HOT Patch - Ready for review
Date: 2007-04-20 07:57:26
Message-ID: 2e78013d0704200057q331fcbc7p4ea96eba42bd79a1@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-patches
On 4/19/07, Heikki Linnakangas <heikki(at)enterprisedb(dot)com> wrote:
>
>
> What's the purpose of the "HeapScanHintPagePrune" mechanism in index
> builds? I lost track of the discussion on create index, is the it
> necessary for correctness?


Its not required strictly for correctness, but it helps us prune the
HOT-chains
while index building. During index build, if we skip a tuple which is
RECENTLY_DEAD, existing transactions can not use the index for queries.
Pruning the HOT-chains reduces the possibility of finding such tuples
while building the index.


A comment in IndexBuildHeapScan explaining
> why it's done would be nice.


I would do that.


In any case a PG_TRY/CATCH block should be
> used to make sure it's turned off after an unsuccessful index build.


Oh thanks. Would do that too

I would wait for other review comments before submitting a fresh patch.
I hope thats ok.

Thanks,
Pavan
-- 

EnterpriseDB     http://www.enterprisedb.com

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