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From: Ingo Schwarze <>
Subject: Re: half-atomically rebuild databases
Date: Wed, 4 Jan 2012 01:09:06 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hi Kristaps,

> It's still debatable whether using recno(3) for the index is a good
> idea.  The general usage is to hit the btree(3) then look up in the
> recno(3)

Right, so typically, we do a full linear search through the
whole large btree(3), doing a substring or even regex match for
each entry, and after that typically a single or a few recno(3)
lookups in the much smaller index.

I'd *guess* almost the whole time is spent in the btree,
so i'm not sure optimizing the recno will buy us anything.
I'd discourage optimizing the recno part without first
confirming that any relevant part of the time is spent there.

In any case, please don't optimize the database format right now.  ;-)

> (btree(3) is harmless, I think, but useless: we don't do
> lexicographic lookup as I'd originally thought).

That statement makes sense to me.

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      parent reply	other threads:[~2012-01-04  0:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-01 15:45 Ingo Schwarze
2012-01-01 15:55 ` Joerg Sonnenberger
2012-01-01 16:29   ` Ingo Schwarze
2012-01-03 12:39     ` Kristaps Dzonsons
2012-01-04  0:29       ` Ingo Schwarze
2012-01-03 12:45     ` Joerg Sonnenberger
2012-01-03 13:07       ` Kristaps Dzonsons
2012-01-03 13:19         ` Joerg Sonnenberger
2012-01-03 13:45           ` Kristaps Dzonsons
2012-01-03 13:49             ` Joerg Sonnenberger
2012-01-03 23:59               ` Ingo Schwarze
2012-01-04  0:09             ` Ingo Schwarze [this message]

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