| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, Jan Wieck <JanWieck(at)yahoo(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Alvaro Herrera <alvherre(at)commandprompt(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Russell Smith <mr-russ(at)pws(dot)com(dot)au> |
| Subject: | Re: Idea for getting rid of VACUUM FREEZE on cold pages |
| Date: | 2010-06-04 15:59:25 |
| Message-ID: | 18960.1275667165@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Fri, Jun 4, 2010 at 11:45 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> The reason for not recommending cassert in production builds is not
>> cost but stability.
> We routinely castigate people for benchmarking done with cassert
> turned on, and tell them their numbers are meaningless.
I didn't say it wasn't expensive ;-). But Kevin's question seemed to
be based on the assumption that runtime cost was the only negative.
It wouldn't be terribly hard to make a variant of cassert that skips
two or three of the most expensive things (particularly memory context
checking and CLOBBER_FREED_MEMORY), and from a cost perspective that
would be totally reasonable to run in production. We haven't done it
because of the stability issue.
regards, tom lane
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