Horton

Re: So, is COUNT(*) fast now?

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2011-10-21T18:33:31Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Remove pg_upgrade dependency on the 'postgres' database existing in the

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Oct 21, 2011 at 2:08 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> What this test case proves is that btree's overhead per index
>> tuple touched is significantly more than the cost of the fastest path
>> through HeapTupleSatisfiesMVCC, which I don't find surprising
>> considering how much sweat has been expended on that code path over the
>> years.

> I think HeapTupleSatisfiesMVCC is probably being skipped anyway in
> this case, since all the heap pages should be PD_ALL_VISIBLE.

Proves my point ;-) ... you're comparing a code path that's been beat on
for *years* with one that just got written.

			regards, tom lane