Performance tests I did with FreeBSD, Linux and PostgreSQL

Jim C. Nasby jim at
Thu Aug 28 16:22:05 PDT 2003

Please do NOT commit this unless it accompanies a major version change!
PGSQL goes to extremes to ensure that you only have to dump/reload on
major version changes (ie: 7.2.x to 7.3.x), and it'd be really bad to
surprise people with this.

I think it would also be a very good idea to see what happens if you try
and open a database with 8K pages using pgsql compiled for 16K pages. If
it doesn't detect the error, I don't think it's worth doing this; it
just seems too risky; though adding a config option to the port makefile
would be a good alternative in that case.

On Wed, Aug 27, 2003 at 10:44:48AM -0700, Sean Chittenden wrote:
> Hrm, that sounds like a good idea to me.  The appropriate patch is
> included (src/include/pg_config_manual.h).  I'll bounce this by the
> PostgreSQL guys to see what their reaction is, but I'm inclined to
> include this patch in the postgresql-devel port for now, and if things
> go well there, possibly in the main postgresql7 port (pending
> feedback).  I haven't ever played with this setting before and would
> welcome feedback from anyone who has (rergardless of their
> results). -sc
> PS You have to re-initdb/reload your data after applying this patch
>    because the size of data on disk has changed.
> -- 
> Sean Chittenden

> Index: src/include/pg_config_manual.h
> ===================================================================
> RCS file: /home/ncvs/pgsql/pgsql-server/src/include/pg_config_manual.h,v
> retrieving revision 1.5
> diff -u -r1.5 pg_config_manual.h
> --- src/include/pg_config_manual.h	4 Aug 2003 00:43:29 -0000	1.5
> +++ src/include/pg_config_manual.h	27 Aug 2003 17:40:12 -0000
> @@ -23,7 +23,7 @@
>   *
>   * Changing BLCKSZ requires an initdb.
>   */
> -#define BLCKSZ	8192
> +#define BLCKSZ	16384
>  /*
>   * RELSEG_SIZE is the maximum number of blocks allowed in one disk

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Jim C. Nasby, Database Consultant                  jim at
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