The following log files are located in the /obs/diagnostic/
directory:
-
postgresql.audit: This log file collects session and object access audit logs. To collect audit logs, you need to enable audit logs . -
postgresql.log: This log file collects PostgreSQL server logs. These logs are always collected and don't need to be enabled.
When a log file rotates, the following occurs:
-
The log file is copied to the
/obs/diagnostic/archive/directory. If a log file with the same name exists in that directory, then it's overwritten. -
The contents of the original rotated log file are deleted so that the file is empty.
-
Log information immediately begins writing to the empty rotated log file. Log information is written to the log file until the file reaches a size or age threshold, at which point it rotates again. Logs rotate so that they don't become too large.
By default, the rotation setting is for each log file to rotate when its size reaches 200 MB. The default rotation doesn't include an age setting.
Archived files are retained for 7 days. Archived files that are older
than 7 days are automatically removed, except for the file that was archived
during the last rotation. For example, if log_rotation_age
is older than 7 days,
then the archived file reaches the 7-day threshold before the rotation of the
current file. In this case, this archived file isn't removed until the next
rotation generates a new archived file.
Each rotated log filename follows this format: postgresql-%Y-%m-%d_%H%M%S.log
.
The timestamp is determined at the time of log rotation and is expressed in
Coordinated Universal Time (UTC). For example, if the log is rotated at
13:01:02 of 12/20/2024 UTC, the archived filename is postgresql-2024-12-20_130102.log
.
Each archived file is individually compressed using the Gzip file format.
Enable audit logs
For session and object access logs to be collected in the postgresql.audit
file, you need to enable the pgaudit
database parameter. To enable pgaudit
,
add the following line to the parameters
section of the v1_dbcluster_parameters.yaml
file under Secret
:
alloydb.enable_pgaudit
:
"on"
The following is an example of this might look like:
apiVersion
:
v1
kind
:
Secret
...
apiVersion
:
alloydbomni.dbadmin.goog/v1
kind
:
DBCluster
metadata
:
name
:
DB_CLUSTER_NAME
spec
:
databaseVersion
:
"16.8.0"
primarySpec
:
...
parameters
:
...
alloydb.enable_pgaudit
:
"on"
For more information, see pgaudit
in Supported database extensions
,
and PostgreSQL Auditing Extension
.
PostgreSQL server logs are always collected in the postgresql.log
file and
don't require enabling pgaudit
.
View the path of the audit log file
The SQL function alloydb_audit_current_logfile
can be used to view the path of the audit log file. If auditing is disabled, then the result is NULL
.
SELECT
alloydb_audit_current_logfile
();
alloydb_audit_current_logfile
/
var
/
log
/
pglogs
/
postgresql
-
2025
-
03
-
28
_042024
.
audit
Configure log rotation
If you want more control over when logs rotate, configure a maximum file size, a duration between log rotations, or both. The duration between log rotations is also called the age of the log. If you use both settings, then each log rotates when it reaches one of the thresholds.
To configure log rotation, you set one or both of the following parameters in
the parameters
section of the DBCluster
manifest:
-
log_rotation_size: " SIZE_IN_KB " -
log_rotation_age: " AGE_IN_MINUTES "
To disable one of the log rotation settings, set it to zero ( "0"
).
To retain the default setting that rotates logs when their file size
reaches 200 MB, don't set either parameter.
Log rotation maximum log size and duration example
The following sample sets logs to rotate when their file size reaches 400 MB or when the time between log rotations reaches one day, whichever happens first:
apiVersion
:
alloydbomni.dbadmin.goog/v1
kind
:
DBCluster
metadata
:
name
:
DB_CLUSTER_NAME
spec
:
...
primarySpec
:
...
parameters
:
log_rotation_size
:
"400000"
# 400 MB
log_rotation_age
:
"1440"
# 24 hours * 60 minutes = 1 day
Log rotation maximum log size example
The following sample sets logs to rotate when their file size reaches 400 MB:
apiVersion
:
alloydbomni.dbadmin.goog/v1
kind
:
DBCluster
metadata
:
name
:
DB_CLUSTER_NAME
spec
:
...
primarySpec
:
...
parameters
:
log_rotation_size
:
"400000"
# 400 MB
log_rotation_age
:
"0"
# Set to 0 to disable
Log rotation duration example
The following sample sets logs to rotate once every 24 hours:
apiVersion
:
alloydbomni.dbadmin.goog/v1
kind
:
DBCluster
metadata
:
name
:
DB_CLUSTER_NAME
spec
:
...
primarySpec
:
...
parameters
:
log_rotation_size
:
"0"
# Set to 0 to disable
log_rotation_age
:
"1440"
# 24 hours * 60 minutes = 1 day
