RE: low priority postmaster threads? - Mailing list pgsql-hackers

From Chris Storah
Subject RE: low priority postmaster threads?
Date
Msg-id C05E7DA1218ED411BF8A00105AC95A8E017AFC20@SV-CNTRMAIL
Whole thread Raw
In response to low priority postmaster threads?  (Chris Storah <cstorah@emis-support.demon.co.uk>)
List pgsql-hackers
Tom Lane Wrote:
> The trouble here is that CPU nice doesn't (on most platforms) change the
> behavior of the I/O scheduler, so this would only be of use to the
> extent that your queries are CPU bound and not I/O bound.

Assuming there is a major processor hit, and the backend has a UW-SCSI RAID
box with enough I/O capability...


>What happens when the low-priority process holds some lock or other,
>and then a higher-priority process comes along and wants the lock?

If the query was a select only, would the locking problem still apply?
(The long queries in this case are in the form of 'select * from [all tables
joined together] where x')

I will make a couple of changes and test it to see if there are any
performance gains in particular cases.
The other option is to add another processor :)

Chris



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