contrib/pg_stat_statements 1212

Here is an updated version of pg_stat_statements.

[Changes]
- A new GUC variable 'explain_analyze_format' is added.
- Statistics counters are converted into a variable 'BufferStats'.

"Vladimir Sitnikov" <sitnikov(dot)vladimir(at)gmail(dot)com> wrote:

> Can I ask my question once again?
> Why don't you want to make "print all the info" the default output format?

I added a new GUC variable 'explain_analyze_format' to print all
statistics counters in EXPLAIN ANALYZE. We can set special variables
into it to get non-default counters. I think everyone don't always
require all the info. Of course TABLE-explain and XML-explain could
handle the counters better, but this patch should not include them.

A variable 'BufferStats' is for cleanup calculations of many separated
counters. It is exported (marked as PGDLLIMPORT) so that users can add
a user-defined view like pg_stat_session_buffer_usage if needed.

Comments welcome.

[Sample output of explain_analyze_format]
=# SET explain_analyze_format = ' gets=%g reads=%r temp=%t cpu=%p';
=# EXPLAIN ANALYZE SELECT * FROM accounts;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------
Seq Scan on accounts (cost=0.00..2640.00 rows=100000 width=97) (actual time=0.054..117.046 rows=100000 loops=1 gets=1640 reads=1608 temp=0 cpu=125.00)
Total runtime: 208.167 ms
(2 rows)

The following special variables are available:
%g : # of shared buffer gets (= %h + %r)
%h : # of shared buffer hits
%r : # of shared buffer reads
%w : # of shared buffer writes
%G : # of local buffer gets (= %H + %R)
%H : # of local buffer hits
%R : # of local buffer reads
%W : # of local buffer writes
%t : # of buffile reads
%T : # of buffile writes
%u : user cpu time
%s : sys cpu time
%p : total cpu times (= %u + %s)

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center