PostGreSQL and zlib

"Hubert FONGARNAND" <informatique.internet@fiducial.fr> writes:

I'm sure it's very easy to implement as a C function that would call zlib

Is there already an implementation of such things?

Not that I'm aware though you might look at pgcrypto. Good crypto has to
compress first so there may be a possibility of just doing the compression.

Postgres also will automatically try to compress data like byteas if the
record is larger than 2kB (1/4 of the block size if you've changed the block
size). So you may not have to do anything if you're just looking to save space
on disk.

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com

The problem is that for TOAST columns :
"The compression technique used is a fairly simple and very fast member
of the LZ family of compression techniques. See
src/backend/utils/adt/pg_lzcompress.c for the details."
With such function you could choose you compression algorithm and
compression level...

Another question : does this TOAST code works for all type of data, like
TEXT (in our case)

Le jeudi 25 octobre 2007 à 11:03 +0100, Gregory Stark a écrit :

"Hubert FONGARNAND" <informatique.internet@fiducial.fr> writes:

I'm sure it's very easy to implement as a C function that would call zlib

Is there already an implementation of such things?

Not that I'm aware though you might look at pgcrypto. Good crypto has to
compress first so there may be a possibility of just doing the compression.

Postgres also will automatically try to compress data like byteas if the
record is larger than 2kB (1/4 of the block size if you've changed the block
size). So you may not have to do anything if you're just looking to save space
on disk.

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On Thu, Oct 25, 2007 at 01:49:57PM +0200, Hubert FONGARNAND wrote:

Another question : does this TOAST code works for all type of data, like
TEXT (in our case)

Yes.

Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/