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Description

It is recommended to set the 3625 (trace flag) database flag for a Cloud SQL SQL Server instance to on.

Rationale​

Microsoft SQL trace flags are frequently used to diagnose performance issues or debug stored procedures or complex systems, but they may also be recommended by Microsoft Support to address behavior that negatively impacts a specific workload. All documented trace flags and those recommended by Microsoft Support are fully supported in a production environment when used as directed. 3625 (trace log) limits the amount of information returned to users who are not members of the sysadmin fixed server role, by masking the parameters of some error messages using ******. Setting this in a Google Cloud flag for the instance helps prevent the disclosure of sensitive information. This recommendation is applicable to SQL Server database instances.

Impact​

Changing flags on a database may cause it to restart. The best time to do this is during a period of low usage.

Audit​

From Google Cloud Console​

  1. Go to the Cloud SQL Instances page in the Google Cloud Console by visiting https://console.cloud.google.com/sql/instances.
  2. Select the instance to open its Instance Overview page.
  3. Ensure the database flag 3625 that has been set is listed under the Database flags section.

From Google Cloud CLI​

  1. Ensure the following command returns on for every Cloud SQL SQL Server database instance:

    gcloud sql instances describe {{instance-name}} \
        --format=json | jq '.settings.databaseFlags[] | select(.name=="3625") | .value'

Default Value​

SQL Server implementations have trace flags turned off by default, as they are used for logging purposes.

References​

  1. https://cloud.google.com/sql/docs/sqlserver/flags
  2. https://docs.microsoft.com/en-us/sql/t-sql/database-console-commands/dbcc-traceon-trace-flags-transact-sql?view=sql-server-ver15#trace-flags
  3. https://github.com/ktaranov/sqlserver-kit/blob/master/SQL%20Server%20Trace%20Flag.md

Additional Information​

WARNING: This patch modifies database flag values, which may require your instance to be restarted. Check the list of supported flags - https://cloud.google.com/sql/docs/sqlserver/flags - to see if your instance will be restarted when this patch is submitted.

Note: some database flag settings can affect instance availability or stability, and remove the instance from the Cloud SQL SLA. For information about these flags, see Operational Guidelines.

Note: Configuring the above flag restarts the Cloud SQL instance.