Grant Overhead
Grants can affect query processing time. Queries for a table or view have overhead if:
• Permissions have been granted on the table or view
• Column-specific permissions are granted
• Many permissions are granted in general in the database
For the following, however, there is no overhead:
• For the table owner
• On certain public grants:
– In select operations
– Any operation for which all allowed permissions are specified for public
• If no permissions qualify (the query is simply aborted)
There is additional overhead during session initialization to evaluate database privileges for the authorization identifiers associated with the session. Because session initialization must read the catalogs in which groups, roles, and database privileges are stored, certain operations issued by the DBA or system administrator that write to these catalogs can be committed or rolled back as soon as possible. These operations include:
• Granting or revoking database privileges
• Creating, altering, or dropping a group
• Creating, altering, or dropping a role
Last modified date: 01/30/2023