Re: REINDEX using only 1 CPU (of 2)

A REINDEX is one process - you can't split one process over 2 CPU's.

If you start another process (a SELECT / UPDATE / INSERT for example), that
process (should) use the other processor.

Cheers,
~p

-----Original Message-----
From: pgsql-admin-owner(at)postgresql(dot)org
[mailto:pgsql-admin-owner(at)postgresql(dot)org] On Behalf Of
ogjunk-pgjedan(at)yahoo(dot)com
Sent: Saturday, 14 April 2007 10:55
To: pgsql-admin(at)postgresql(dot)org
Subject: [ADMIN] REINDEX using only 1 CPU (of 2)

Hi,

I've got PG 8.2.3 running on a dual-core P4, and I noticed that, at least
during reindexing, postgreSQL REINDEX process is using only 1 of those 2
cores. You can clearly see this from this snippet from top:

Cpu0 : 93.3% us, 6.7% sy, 0.0% ni, 0.0% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu1 : 0.0% us, 2.6% sy, 0.0% ni, 85.5% id, 11.8% wa, 0.0% hi, 0.0% si

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

21909 pg 25 0 116m 89m 42m R 98.9 9.2 1:01.92 postgres: pg mydb
[local] REINDEX

This PG 8.2.3 was compiled from sources on this box, so if there is anything
in the config/install process that should pick up that this box has "2"
CPUs, perhaps that didn't happen? I know I didn't manually instruct the
config/install that the box is a dual-core box. This is running on a Linux
box with the SMP-aware kernel.

Is this a known limitation? Am I reading this wrong?

Thanks,
Otis

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