pgsql: Clamp last_anl_tuples to n_live_tuples, in case we vacuum a table
Log Message:
-----------
Clamp last_anl_tuples to n_live_tuples, in case we vacuum a table without
analyzing, so that future analyze threshold calculations don't get confused.
Also, make sure we correctly track the decrease of live tuples cause by
deletes.
Per report from Dylan Hansen, patches by Tom Lane and me.
Modified Files:
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pgsql/src/backend/postmaster:
pgstat.c (r1.130 -> r1.131)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/pgstat.c.diff?r1=1.130&r2=1.131)
Alvaro Herrera wrote:
Clamp last_anl_tuples to n_live_tuples, in case we vacuum a table without
analyzing, so that future analyze threshold calculations don't get confused.
Also, make sure we correctly track the decrease of live tuples cause by
deletes.
Now that the values of n_live_tuples and n_dead_tuples are correct,
maybe we should expose them in functions like n_tuples_inserted and all
the rest? Probably n_live_tuples is not as useful (because you can get
a very similar, if not equal, value from pg_class.reltuples), but
n_dead_tuples seems worthwhile. I'd also add them to pg_stat_all_tables.
On a loosely related matter, how about changing pg_class.relpages to
pg_class.reldensity? The idea being that instead of storing the number
of pages, we store the average tuple density, which is what we use
relpages for anyway.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
Alvaro Herrera <alvherre@commandprompt.com> writes:
On a loosely related matter, how about changing pg_class.relpages to
pg_class.reldensity?
IIRC, I considered this earlier, and rejected it because it doesn't cope
well with the corner case relpages == 0. Also, it'll break existing
clients that expect to find relpages and reltuples, if there are any
--- which is not a very strong argument, certainly, but the argument in
favor of changing seems even weaker.regards, tom lane
-----Original Message-----
From: pgsql-hackers-owner@postgresql.org
[mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Tom Lane
Sent: 27 June 2006 05:12
To: Alvaro Herrera
Cc: Hackers
Subject: Re: [HACKERS] [COMMITTERS] pgsql: Clamp
last_anl_tuples to n_live_tuples, in case we vacuum a tableAlvaro Herrera <alvherre@commandprompt.com> writes:
On a loosely related matter, how about changing pg_class.relpages to
pg_class.reldensity?IIRC, I considered this earlier, and rejected it because it
doesn't cope
well with the corner case relpages == 0. Also, it'll break existing
clients that expect to find relpages and reltuples, if there are any
There are.
/D