Re: controlling process priority - Mailing list pgsql-sql

From Peter T. Brown
Subject Re: controlling process priority
Date
Msg-id 001501c1897b$8dc5ae90$7d00000a@PETER
Whole thread Raw
In response to Re: controlling process priority  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-sql
I had an idea last night that addresses the process priority and the locking
issue: use LIMIT with an offset in a long running thread to programmatically
throttle the backend processing.

This works only because I am storing all the results to my queries as
pointers in a temporary table (then using those values as the basis for
subsequent queries).



-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Thursday, December 20, 2001 7:10 AM
To: Robert B. Easter
Cc: Peter T. Brown; pgsql-sql@postgresql.org
Subject: Re: [SQL] controlling process priority


"Robert B. Easter" <reaster@comptechnews.com> writes:
> [ C function to nice down the backend ]

This sort of thing has been suggested before, but I've always wondered
whether it isn't counterproductive.  The trouble is priority inversion:
any time the niced backend is holding a lock on some shared
datastructure, it will be blocking the allegedly-higher-priority other
backends.
        regards, tom lane



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