Re: Need help - Regarding Data Compression in PostgreSQL.

Scott Marlowe escribió:
> On Tue, Dec 16, 2008 at 6:52 AM, salma <salma(dot)khanam(at)applabs(dot)com> wrote:

> > 2. What kind of compression, if any, is available in PostgreSQL.
>
> Standard unix compress I believe

No, it's our own LZ implementation, which is focused on speed but does
not compress as well as gzip or compress (see
src/backend/utils/adt/pg_lzcompress.c for more details)

> > 3. If compression is available, what kind of disk space savings can I expect
> > using it.
>
> depends on how compressible your data is. The compression that's
> built into pgsql is focused on speed, not compression. So don't
> expect 99% compression or anything.

Well, you can compress 200 constant bytes to 4 with our algorithm, so
it's 98% :-) (plus the varlena header though)

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support