Logging slow queries on Google Cloud SQL PostgreSQL instances

The possibility of monitoring slow PostgreSQL queries for Cloud SQL instances is currently not available. As you comment, the log_min_duration_statement flag is currently not supported by Cloud SQL.

Right now, work is being made on adding this feature to Cloud SQL, and you can keep track on the progress made through this link. You can click on the star icon on the top left corner to get email notifications whenever any significant progress has been achieved.

April 3, 2019 UPDATE

It is now possible to log slow queries on Google Cloud SQL PostgreSQL instances, see https://cloud.google.com/sql/docs/release-notes#april_3_2019:

database_flags = [
  {
    name = "log_min_duration_statement"
    value = "1000"
  },
]

Once you enable log_min_duration_statement, you can view the logs using Stackdriver logging. Select Cloud SQL Database -> cloudsql.googleapis.com/postgres.log and you will see the log like this.

[103402]: [9-1] db=cloudsqladmin,user=cloudsqladmin LOG: duration: 11.211 ms statement: [YOUR SQL HERE]

References:

• Full list of supported flags (CTRL+F for log_min_duration_statement): https://cloud.google.com/sql/docs/postgres/flags#postgres-l
• Issue tracker: https://issuetracker.google.com/issues/74578509#comment54
• PostgreSQL docs: https://www.postgresql.org/docs/9.6/runtime-config-logging.html#GUC-LOG-MIN-DURATION-STATEMENT