Horton

Re: Query is over 2x slower with jit=on

Lukas Fittl <lukas@fittl.com>

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From: Lukas Fittl <lukas@fittl.com>
To: Andres Freund <andres@anarazel.de>
Cc: Amit Khandekar <amitdkhan.pg@gmail.com>, Andreas Joseph Krogh <andreas@visena.com>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, "Jonathan S. Katz" <jkatz@postgresql.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-10-01T07:32:18Z
Lists: pgsql-hackers

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On Tue, Sep 25, 2018 at 1:17 PM, Andres Freund <andres@anarazel.de> wrote:
>
> I've pushed the change without that bit - it's just a few additional
> lines if we want to change that.
>

It seems that since this commit, JIT statistics are now only being printed
for parallel query plans. This is due to ExplainPrintJIT being called
before ExecutorEnd, so in a non-parallel query,
queryDesc->estate->es_jit_combined_instr will never get set.

Attached a patch that instead introduces a new ExplainPrintJITSummary
method that summarizes the statistics before they get printed.

I've also removed an (I believe) unnecessary "if (estate->es_instrument)"
check that prevented EXPLAIN without ANALYZE from showing whether JIT would
be used or not.

In addition this also updates a missed section in the documentation with
the new stats output format.

Best,
Lukas

-- 
Lukas Fittl

Commits

  1. Fix issues around EXPLAIN with JIT.

  2. Collect JIT instrumentation from workers.

  3. Make EXPLAIN output for JIT compilation more dense.

  4. Save/restore SPI's global variables in SPI_connect() and SPI_finish().

  5. Rationalize handling of single and double quotes in bootstrap data.