| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL-patches <pgsql-patches(at)postgresql(dot)org> |
| Subject: | Re: HOT patch - version 15 |
| Date: | 2007-09-05 17:25:46 |
| Message-ID: | 200709051725.l85HPkH08347@momjian.us |
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| Lists: | pgsql-patches |
Pavan Deolasee wrote:
> together. In the SELECT path, we conditionally try for exclusive lock. If
> the exclusive lock is also cleanup lock, we prune and defrag the page.
> As the patch stands, during index fetch we try to prune only the chain
> originating at that tuple. I am wondering if we should change that
> and prune all the tuple chains in the page ?
I am thinking we are best just doing the index chain we already have to
read.
If you are modifying the table (like with UPDATE) it makes sense to be
more aggressive and do the whole page because you know there are
probably other table modifications, but for an index lookup there isn't
any knowledge of whether the table is being modified so looking at more
than we need seems like overkill.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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