The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/12/runtime-config-logging.html Description:
Hi all: We recently ran into an unusual case where the following occurred: - PG log directory is a separate filesystem from PG data and other operations-critical data. - PG logs directory filled to 100% usage due to outside circumstances (PG continued functioning, despite logging issues) - Once disk usage issue was resolved (disk space was again available), the log file would not rotate on time/size based triggers and would continue to grow in size. - Log rotation would only resume after issuing a SIGHUP I believe that this case would be ideally documented (https://www.postgresql.org/docs/current/runtime-config-logging.html), as it's a valid state based on the code: https://github.com/postgres/postgres/blob/c96581abe418a3bf64b643aa4e27091d1eaea1c1/src/backend/postmaster/syslogger.c Specifically highlighting the sections: ``` /* * If we had a rotation-disabling failure, re-enable rotation * attempts after SIGHUP, and force one immediately. */ if (rotation_disabled) { rotation_disabled = false; rotation_requested = true; } ``` I will note that it is logged in PG Log output as noted below: ``` /* * ENFILE/EMFILE are not too surprising on a busy system; just * keep using the old file till we manage to get a new one. * Otherwise, assume something's wrong with Log_directory and stop * trying to create files. */ if (errno != ENFILE && errno != EMFILE) { ereport(LOG, (errmsg("disabling automatic rotation (use SIGHUP to re-enable)"))); rotation_disabled = true; } ``` However, it is also notable that because these logs are not rotated as expected, one may not see the above error message unless they sort through a log file on an unexpected date/time. Further, I'm not sure how that message would ever even get logged if rotation is halted due to disk filling up. I believe this could be rectified by noting the situations where log rotation would be disabled (such as the disk full state described) and the action to resume log rotation (issue a SIGHUP to re-enable) in the https://www.postgresql.org/docs/current/runtime-config-logging.html page. Cheers,
