When looking at PG load in QAN, if tables query touches are in a schema other than public, you can't see table structure. All you get is "Table not found: sql: no rows in result set". See the following picture for how it looks:
Expected result: table structure should be output regardless of table schema.
A bit more elaborate explanation: PMM expects that a database user it uses can see the inspected table in its search path, which is not true, unless pmm user's search path lists every schema in every database simultaneously.
To reproduce, run two pgbench processes. One against public schema, and one against any other schema. Providing some steps:
Once PMM picks up some data, you should be able to see in QAN that when inspecting queries running against pgbench_public database you can view table structure, and see "Table not found: sql: no rows in result set" for queries over pgbench_nopublic.
Note that using public schema for user objects is discouraged and a recommended practice is to remove public schema from the search path: https://www.postgresql.org/docs/13/ddl-schemas.html#DDL-SCHEMAS-PATTERNS
To make describe table work in my reproduction scenario, run alter user pmm set search_path = "$user", public, pgbench;.