Hi, I am trying to increase performances of Postgres by changing some
memory parameters according to this document:

http://www.powerpostgresql.com/Downl...d_conf_80.html

the problem is that when I try to increase memory parameters Postgres
get a fatal error. I tried to raise the shared_buffers parameter to
something slightly bigger than the default 24 megs (32 mega), and/or
tried to increase max_fsm_pages as twice the default.
I am working on a Ubuntu server 64 bit 8.04 LTS with 8 Gbytes of memory.
Do you know any good reference that explains how to get Postgres using
effectiveness all that memory?

I get this:

* Restarting PostgreSQL 8.3 database server
* The PostgreSQL
server failed to start. Please check the log output:
2008-10-23 15:18:46 CEST LOG: could not load root certificate file
"root.crt": no SSL error reported
2008-10-23 15:18:46 CEST DETAIL: Will not verify client certificates.
2008-10-23 15:18:46 CEST FATAL: could not create shared memory segment:
Invalid argument
2008-10-23 15:18:46 CEST DETAIL: Failed system call was
shmget(key=5432001, size=35184640, 03600).
2008-10-23 15:18:46 CEST HINT: This error usually means that
PostgreSQL's request for a shared memory segment exceeded your kernel's
SHMMAX parameter. You can either reduce the request size or reconfigure
the kernel with larger SHMMAX. To reduce the request size (currently
35184640 bytes), reduce PostgreSQL's shared_buffers parameter (currently
3072) and/or its max_connections parameter (currently 103).
If the request size is already small, it's possible that it is
less than your kernel's SHMMIN parameter, in which case raising the
request size or reconfiguring SHMMIN is called for.
The PostgreSQL documentation contains more information about
shared memory configuration.

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato wrote:
I have had the same experience a couple of times. Even after reading the
documentation I did not succeed in changing parameters like shared buffers.

I would be really interested in a good tutorial on this matter.

Silvio

Coniglio Sgabbiato schrieb:
Maybe you need to adopt the kernel parameter acordingly, just as the
error message is suggesting?

What is the output when you issue cat /proc/sys/kernel/shmmax ?

Regards,

Egon