Thread: pgsql: Include planning time in EXPLAIN ANALYZE output.
Include planning time in EXPLAIN ANALYZE output. This doesn't work for prepared queries, but it's not too easy to get the information in that case and there's some debate as to exactly what the right thing to measure is, so just do this for now. Andreas Karlsson, with slight doc changes by me. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/9347baa5bbc70368f2f01438bbb8116863dac1ec Modified Files -------------- doc/src/sgml/perform.sgml | 27 +++++++++++++++++++++++++++ doc/src/sgml/ref/explain.sgml | 17 ++++++++++++----- src/backend/commands/explain.c | 24 +++++++++++++++++++++--- src/backend/commands/prepare.c | 2 +- src/include/commands/explain.h | 4 ++-- 5 files changed, 63 insertions(+), 11 deletions(-)
On Wed, Jan 29, 2014 at 1:10 PM, Robert Haas <rhaas@postgresql.org> wrote: > Include planning time in EXPLAIN ANALYZE output. Isn't it perhaps a little confusing that "Planning time" may well exceed "Total runtime"? I'm aware that we aren't super clear on the accounting here generally, as with pg_stat_statements, which doesn't include planning time in total_time, while we aren't even explicit about that in the documentation. But even still, seeing the two side-by-side, with planning time > total runtime did give me pause. -- Peter Geoghegan
Peter Geoghegan <pg@heroku.com> writes:
> On Wed, Jan 29, 2014 at 1:10 PM, Robert Haas <rhaas@postgresql.org> wrote:
>> Include planning time in EXPLAIN ANALYZE output.
> Isn't it perhaps a little confusing that "Planning time" may well
> exceed "Total runtime"?
Perhaps s/Total runtime/Execution time/ ?
regards, tom lane
On Sun, Feb 2, 2014 at 8:13 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Perhaps s/Total runtime/Execution time/ ? +1 -- Peter Geoghegan
On 03/02/14 09:44, Peter Geoghegan wrote: > On Sun, Feb 2, 2014 at 8:13 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> Perhaps s/Total runtime/Execution time/ ? > +1 > > If the planning was ever made into a parallel process, then 'elapsed time' would be less than the 'processor time'. So what does 'Execution time' mean? Can I assume: 'Total runtime' is 'elapsed time' and 'Execution time' is 'processor time'. In a parallel implementation, one would likely want both. Possible this is not an issue now, and I'm thinking to far ahead! Cheers, Gavin
Gavin Flower <GavinFlower@archidevsys.co.nz> writes:
> Can I assume:
> 'Total runtime' is 'elapsed time'
> and
> 'Execution time' is 'processor time'.
No. It's going to be elapsed time, either way.
> In a parallel implementation, one would likely want both.
When and if we have that, we can argue about what to measure.
regards, tom lane