Configuring EDB Query Advisor

To run EDB Query Advisor, you need to add it to shared_preload_libraries and create the extension in the database.

1. In the postgresql.conf file, add query_advisor to the shared_preload_libraries parameter:

   → WrapCopy

   shared_preload_libraries = 'query_advisor'

   Note

   If shared_preload_libraries has other extensions, then you can add query_advisor to the list. The order doesn't matter.

2. Restart Postgres.

3. Create the EDB Query Advisor extension in your database:

   → WrapCopy

   CREATE EXTENSION query_advisor;

Parameters

The following custom GUCs control the EDB Query Advisor extension behavior.

If you modify these parameters, then reload Postgres to apply the changes:

• query_advisor.enabled — Specifies whether to enable query_advisor. It takes a Boolean value. The default is true.
• query_advisor.sample_rate — Sets the fraction of queries to sample. It takes a double value. For example, 0.1 indicates to sample only 1 out of 10 queries. The default is -1, which specifies automatic and results in a value of 1 / max_connections.

If you modify these parameters, then restart Postgres to apply the changes:

• query_advisor.max_qual_entries — Sets the maximum number of predicates tracked. The default is 100000.
• query_advisor.max_workload_entries — Sets the maximum number of workload queries tracked. The default is 100000.
• query_advisor.max_workload_query_size — Sets the maximum size of the workload query. The default is 1024 bytes.