thread-index: AccFafeYkNg8N1GHSv+S1M+xr7yevg==
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Subject: Re: [PERFORM] BUG #2737: hash indexing large table fails,
	while btree of same index works
From: "Simon Riggs" <simon@2ndquadrant.com>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Balazs Nagy" <bnagy@thenewpush.com>, <pgsql-bugs@postgresql.org>,
	<pgsql-performance@postgresql.org>
In-Reply-To: <7530.1163202951@sss.pgh.pa.us>
References: <200611051347.kA5DlVCk032222@wwwmaster.postgresql.org>
	<7530.1163202951@sss.pgh.pa.us>
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Date: Sat, 11 Nov 2006 08:17:54 +0000
Message-ID: <1163233075.3634.944.camel@silverbirch.site>
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On Fri, 2006-11-10 at 18:55 -0500, Tom Lane wrote:
> [ cc'ing to pgsql-performance because of performance issue for hash indexes ]
> 
> "Balazs Nagy" <bnagy@thenewpush.com> writes:
> > Database table size: ~60 million rows
> > Field to index: varchar 127
> 
> > CREATE INDEX ... USING hash ...

I'd be interested in a performance test that shows this is the best way
to index a table though, especially for such a large column. No wonder
there is an 8GB index.

> One thought that comes to mind is to require hash to do an smgrextend()
> addressing the last block it intends to use whenever it allocates a new
> batch of blocks, whereupon md.c could adopt a saner API: allow
> smgrextend but not other calls to address blocks beyond the current EOF.

> Thoughts?

Yes, do it. 

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com