Horton

Re:pg_stat_statements and "IN" conditions

Sergei Kornilov <sk@zsrv.org>

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From: Sergei Kornilov <sk@zsrv.org>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Marcos Pegoraro <marcos@f10.com.br>, vignesh C <vignesh21@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Zhihong Yu <zyu@yugabyte.com>, David Steele <david@pgmasters.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Greg Stark <stark@mit.edu>, Pavel Trukhanov <pavel.trukhanov@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2023-02-07T20:14:52Z
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. Introduce squashing of constant lists in query jumbling

  2. Make documentation builds reproducible

  3. Include values of A_Const nodes in query jumbling

  4. Teach planner about more monotonic window functions

  5. Split up guc.c for better build speed and ease of maintenance.

Hello!

Unfortunately, rebase is needed again due to recent changes in queryjumblefuncs ( 9ba37b2cb6a174b37fc51d0649ef73e56eae27fc )

It seems a little strange to me that with const_merge_threshold = 1, such a test case gives the same result as with const_merge_threshold = 2

select pg_stat_statements_reset();
set const_merge_threshold to 1;
select * from test where i in (1,2,3);
select * from test where i in (1,2);
select * from test where i in (1);
select query, calls from pg_stat_statements order by query;

                query                | calls 
-------------------------------------+-------
 select * from test where i in (...) |     2
 select * from test where i in ($1)  |     1

Probably const_merge_threshold = 1 should produce only "i in (...)"?

const_merge_threshold is "the minimal length of an array" (more or equal) or "array .. length is larger than" (not equals)? I think the documentation is ambiguous in this regard.

I also noticed a typo in guc_tables.c: "Sets the minimal numer of constants in an array" -> number

regards, Sergei