From: | Jon Nelson <jnelson+pgsql(at)jamponi(dot)net> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: problems with set_config, work_mem, maintenance_work_mem, and sorting |
Date: | 2012-02-28 21:38:12 |
Message-ID: | CAKuK5J0+Rpt3rwQJLCrzgBj-ShJWhVjxSAPS8tJSLOYGB4QA=Q@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
On Tue, Feb 28, 2012 at 2:51 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Jon Nelson <jnelson+pgsql(at)jamponi(dot)net> writes:
>> On Tue, Feb 28, 2012 at 1:28 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Jon Nelson <jnelson+pgsql(at)jamponi(dot)net> writes:
>>>> Why does PostgreSQL /sometimes/ use the globally-configured values and
>>>> sometimes use the values that come from the connection?
>
>>> You sure those log entries are all from the same process?
>
>> If I am understanding this correctly, yes. They all share the same pid.
>
> Hmph ... does seem a bit weird. Can you turn on log_statements and
> identify which operations aren't using the session values?
I had log_min_duration_statement = 1000.
An example:
LOG: 00000: begin tuple sort: nkeys = 3, workMem = 131072, randomAccess = f
LOCATION: tuplesort_begin_heap, tuplesort.c:573
STATEMENT: INSERT INTO (new table) SELECT (bunch of stuff here) FROM
.. ORDER BY ...
and also some CREATE TABLE ... statements:
LOG: 00000: begin index sort: unique = f, workMem = 131072, randomAccess = f
LOCATION: tuplesort_begin_index_btree, tuplesort.c:642
STATEMENT: CREATE TABLE <tablename> (LIKE some_other_tablename)
I also see this:
LOG: 00000: begin tuple sort: nkeys = 2, workMem = 131072, randomAccess = f
LOCATION: tuplesort_begin_heap, tuplesort.c:573
STATEMENT: SELECT <bunch of stuff from system catalogs>
which is the ORM library (SQLAlchemy) doing a reflection of the
table(s) involved.
The statement is from the same backend (pid) and takes place
chronologically *after* the following:
LOG: 00000: begin tuple sort: nkeys = 2, workMem = 1048576, randomAccess = f
LOCATION: tuplesort_begin_heap, tuplesort.c:573
STATEMENT: <more reflection stuff>
Is that useful?
If that's not enough, I can crank the logging up.
What would you like to see for 'log_statements' (if what I've provided
you above is not enough).
--
Jon
From | Date | Subject | |
---|---|---|---|
Next Message | Kääriäinen Anssi | 2012-02-28 21:48:52 | Re: problems with set_config, work_mem, maintenance_work_mem, and sorting |
Previous Message | Tom Lane | 2012-02-28 20:51:54 | Re: problems with set_config, work_mem, maintenance_work_mem, and sorting |