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Re: guile-db

From: Linas Vepstas
Subject: Re: guile-db
Date: Wed, 15 Oct 2008 14:08:35 -0500

2008/10/14 betoes <address@hidden>:
> On Tue, 2008-10-14 at 15:38 -0500, Linas Vepstas wrote:
> 2008/10/14 betoes <address@hidden>:
>> Hello list,
>> In the Debian distro, there is a packge named guile-db, which refers to a
>> Berkeley DB wrap for Guile. Do someone know if it is active? If there is a
>> repository or web page? I tried the maintainer and author e-mails with no
>> success.
> Dunno. However, fyi, I'm maintaining guile-dbi, which wraps
> postgres and mysql.
> guile-dbi is great! I'm using it, thanks!
> Berkeley DB is a low-level database, not a high level as SQL flavors, it can
> be used as the base of them, it is GPL.

I know what BDB is.

I tend to avoid it because it's performance can be disasterous
for certain database loads. I (re-)discovered this summer that
BDB insists on always flushing key indexes to disk, and there seems to
be no way to tell it to not do this.  This is OK, I guess,
if you need your DB to be hardend against index corruption in
the event of a power failure, but it sucks for performance.

If you are trying to create an new DB by adding
millions of new key-value pairs, this "feature" is utterly
un-needed (if there's a power failure, just rebuild the DB
from scratch) and it will absolutely kill performance.  By
contrast, you can tell Postgres to not build indexes until
later, and to not write anything to disk for as long as it can.
For this case, postgres is orders of magnitude faster than
BDB, taking hours instead of days to build multi-million
record databases..

I was unable to find any way of turning off this "feature"
in BDB, so for me, its a non-starter. Shame, since otherwise
for me, I don't need 99% of the rest of SQL, and BDB might
indeed have been simpler/faster on the query side.


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