Re: Synchronized Scan update - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Synchronized Scan update
Date
Msg-id 3631.1173804812@sss.pgh.pa.us
Whole thread Raw
In response to Re: Synchronized Scan update  (Jeff Davis <pgsql@j-davis.com>)
Responses Re: Synchronized Scan update  (Jeff Davis <pgsql@j-davis.com>)
Re: Synchronized Scan update  (Hannu Krosing <hannu@skype.net>)
List pgsql-hackers
Jeff Davis <pgsql@j-davis.com> writes:
> I agree that ss_report_loc() doesn't need to report on every call. If
> there's any significant overhead I agree that it should report less
> often. Do you think that the overhead is significant on such a simple
> function?

One extra LWLock cycle per page processed definitely *is* a significant
overhead ... can you say "context swap storm"?  I'd think about doing it
once every 100 or so pages.
        regards, tom lane


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: Daylight Saving Time question PostgreSQL 8.1.4
Next
From: Jeff Davis
Date:
Subject: Re: Synchronized Scan update