logs of postgresql and pid-stamping. possible improvement?

On Thu, Aug 15, 2002 at 11:48:40AM +0200, Hubert depesz Lubaczewski wrote:

hi,
is there any way, one could spent some time to allow *full* pid-stamping
in logs?
right now logs look like:
[5703] LOG: query: select *
from
pg_class
WHERE
relname='pg_class';
[5703] LOG: QUERY STATISTICS
! system usage stats:
! 0.028300 elapsed 0.000000 user 0.000000 system sec
! [0.020000 user 0.010000 sys total]
! 0/0 [0/0] filesystem blocks in/out
! 9/7 [305/148] page faults/reclaims, 0 [0] swaps
! 0 [0] signals rcvd, 0/0 [0/0] messages rcvd/sent
! 0/0 [0/0] voluntary/involuntary context switches
! postgres usage stats:
! Shared blocks: 3 read, 0 written, buffer hit rate = 96,55%
! Local blocks: 0 read, 0 written, buffer hit rate = 0,00%
! Direct blocks: 0 read, 0 written

Yes, but all that stuff with the ! at the beginning is associated
with the LOG: QUERY STATISTICS ahead of it, no? Isn't that enough of
a separator to make it clear? Or am I missing something (likely)?

A

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Andrew Sullivan                               87 Mowat Avenue 
Liberty RMS                           Toronto, Ontario Canada
<andrew@libertyrms.info>                              M6K 3E3
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Andrew Sullivan <andrew@libertyrms.info> writes:

Yes, but all that stuff with the ! at the beginning is associated
with the LOG: QUERY STATISTICS ahead of it, no? Isn't that enough of
a separator to make it clear? Or am I missing something (likely)?

He's concerned about query stats printed by concurrent backends becoming
interleaved in the log file. A fair concern, but I don't think it's
real, at least not since 7.2.

As of 7.2, the whole multiline stats message will be written in a
single write() call, so I'd be pretty surprised if it got interleaved
with other processes' messages. At least on HPUX, this is guaranteed
not to happen when stderr is a pipe, so if you're piping the postmaster
log to some kind of log rotation script then it ought to be quite safe.
Possibly if the log is a plain disk file there might be trouble on some
kernels.

If you're logging via syslog() then it's a different story: each line is
sent to syslog individually, I believe. But syslog already marks each
line with PID.

regards, tom lane

On Thu, 2002-08-15 at 13:13, Tom Lane wrote:

Andrew Sullivan <andrew@libertyrms.info> writes:

Yes, but all that stuff with the ! at the beginning is associated
with the LOG: QUERY STATISTICS ahead of it, no? Isn't that enough of
a separator to make it clear? Or am I missing something (likely)?

He's concerned about query stats printed by concurrent backends becoming
interleaved in the log file. A fair concern, but I don't think it's
real, at least not since 7.2.

As of 7.2, the whole multiline stats message will be written in a
single write() call, so I'd be pretty surprised if it got interleaved
with other processes' messages. At least on HPUX, this is guaranteed
not to happen when stderr is a pipe, so if you're piping the postmaster
log to some kind of log rotation script then it ought to be quite safe.
Possibly if the log is a plain disk file there might be trouble on some
kernels.

If you're logging via syslog() then it's a different story: each line is
sent to syslog individually, I believe. But syslog already marks each
line with PID.

and with multi-line messages, it gives a message number-line number tag
as well. (I remember putting in the smarter breakup code in 7.1
(IIRC)).

LER

--
Larry Rosenman http://www.lerctr.org/~ler
Phone: +1 972-414-9812 E-Mail: ler@lerctr.org
US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749