Re: [PERFORM] DELETE vs TRUNCATE explanation

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Daniel Farina <daniel(at)heroku(dot)com>, Craig Ringer <ringerc(at)ringerc(dot)id(dot)au>, Harold A(dot) Giménez <harold(dot)gimenez(at)gmail(dot)com>
Subject: Re: [PERFORM] DELETE vs TRUNCATE explanation
Date: 2012-07-16 16:57:39
Message-ID: 13011.1342457859@sss.pgh.pa.us
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> In my view, the elephant in the room here is that it's dramatically
> inefficient for every backend to send an fsync request on every block
> write.

Yeah. This was better before the decision was taken to separate
bgwriter from checkpointer; before that, only local communication was
involved for the bulk of write operations (or at least so we hope).
I remain less than convinced that that split was really a great idea.

regards, tom lane

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