We often use "set" in .test files to alter query options. Theoretically, a "set" command should change the session-level query options and in most cases a single .test file is executed from the same Impala session. However, for some options using "set" within a query section does not seem to work. For example, "num_nodes" does not work as expected as shown below.
Corresponding .test file:
After running the test above, I validated that the 3 queries were run from the same session, and that the queries run a distributed plan. The "num_nodes" option was definitely not picked up. I am not sure which query options are affected. In several .test files setting other query options does seem to work as expected.
I suspect that the test framework might keep its own list of default query options which get submitted together with the query, so the session-level options are overridden on a per-request basis. For example, if I change the pytest to remove the "num_nodes" dictionary entry, then the test works as expected.