Horton

Re: Re: pg_stat_statements normalisation without invasive changes to the parser (was: Next steps on pg_stat_statements normalisation)

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <peter@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@gmail.com>, PG Hackers <pgsql-hackers@postgresql.org>
Date: 2012-04-09T15:18:43Z
Lists: pgsql-hackers

Commits

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

  1. Restructure SELECT INTO's parsetree representation into CreateTableAsStmt.

  2. Extend the parser location infrastructure to include a location field in

  3. Teach eval_const_expressions() to simplify an ArrayCoerceExpr to a constant

Peter Geoghegan <peter@2ndquadrant.com> writes:
> Having taken another look at the code, I wonder if we wouldn't have
> been better off just fastpathing out of pgss_store in the first call
> (in a pair of calls made by a backend as part an execution of some
> non-prepared query) iff there is already an entry in the hashtable -
> after all, we're now going to the trouble of acquiring the spinlock
> just to increment the usage for the entry by 0 (likewise, every other
> field), which is obviously superfluous. I apologise for not having
> spotted this before submitting my last patch.

On reflection, we can actually make the code a good bit simpler if
we push the responsibility for initializing the usage count correctly
into entry_alloc(), instead of having to fix it up later.  Then we
can just skip the entire adjust-the-stats step in pgss_store when
building a sticky entry.  See my commit just now.

			regards, tom lane