Re: Postgres 9.6.2 and pg_log

De : David G. Johnston [mailto:david(dot)g(dot)johnston(at)gmail(dot)com]
Envoyé : Monday, April 24, 2017 1:34 PM
À : Mark Watson
Cc : (pgsql-general(at)postgresql(dot)org)
Objet : Re: [GENERAL] Postgres 9.6.2 and pg_log

On Mon, Apr 24, 2017 at 8:43 AM, Mark Watson <mark(dot)watson(at)jurisconcept(dot)ca<mailto:mark(dot)watson(at)jurisconcept(dot)ca>> wrote:
Good day all,

I just noticed an anomaly regarding the logging. I have my logging set up as follows:
log_filename = 'postgresql-%d.log'
log_truncate_on_rotation = on

​I don't see "log_rotation_age" and/or "log_rotation_size" here [1] and at least one needs to be set in order to enable actual rotation; the "truncate" option simply tells PostgreSQL what to do when encountering a file with the same name during the rotation process.​

log_rotation_age apparently has under-documented intelligence since I would expect a server that starts up mid-hour and uses a 60 minute rotation to rotate mid-hour as well so the log would contain 1 hours worth of data but the leading hours would be different. The examples in log_truncate_on_rotation indicate that this isn't the case. I have not tested reality or read the source.

This is on Windows 10, 64-bit
PostgreSQL 9.2.2, compiled by Visual C++ build 1800, 64-bit
(EnterpriseDB installer)

Note that this is not a major concern on my end; postgres 9.6.2 has otherwise been running flawlessly.

​Um...you're reporting a very outdated 9.2 release in the supposed copy-paste job above but claiming 9.6.2 ...

[1] https://www.postgresql.org/docs/9.6/static/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-WHERE

David J.

Thanks, David,
The lines log_rotation_age and log_rotation_size are commented, and currently are:
#log_rotation_age = 1d # Automatic rotation of logfiles will
# happen after that time. 0 disables.
#log_rotation_size = 10MB # Automatic rotation of logfiles will
# happen after that much log output.
# 0 disables.

I see from your reference article that the log_rotation_age is now in minutes, and I will adjust that to 1440 (1 day). I don’t know where the “1d” came from. I know it used to be like this in earlier versions.

Mark Watson