Message-ID: <4E73F22F.9@fuzzy.cz>
Date: Sat, 17 Sep 2011 03:04:47 +0200
From: Tomas Vondra <tv@fuzzy.cz>
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To: pgsql-performance@postgresql.org
Subject: Re: Hash index use presently(?) discouraged since 2005:
	revive or bury it?
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Dne 15.9.2011 01:40, Tom Lane napsal(a):
> Stefan Keller <sfkeller@gmail.com> writes:
>> 2011/9/14 Tom Lane <tgl@sss.pgh.pa.us> writes:
>>> (...) I think that
>>> the current state of affairs is still what depesz said, namely that
>>> there might be cases where they'd be a win to use, except the lack of
>>> WAL support is a killer.  I imagine somebody will step up and do that
>>> eventually.
> 
>> How much of work (in man days) do you estimate would this mean for
>> someone who can program but has to learn PG internals first?
> 
> No idea ... I'm probably not the best person to estimate how long it
> would take someone to get up to speed on the relevant internals,
> but I'm sure that would take longer than actually doing the work.
> While it's not a trivial task, I think it fits the definition of
> "a small matter of programming": a piece of code whose anticipated
> length is significantly greater than its complexity.

We've been asked by a local university for PostgreSQL-related topics of
theses and seminary works, so I'm wondering if adding WAL support to
hash indexes would be a good fit ...

Can anyone estimate if a student with reasonable C-knowledge a can
implement this in about 4 months? It seems like a reasonable amount of
research and work to me.

Tomas

PS: All interesting thesis ideas are welcome.