To issue the query in ACT with a fetch-count of 100 and a fetch-limit of 1000:
\set fetch-count 100 \set fetch-limit 1000 SELECT * FROM FOO, BAR where FOO.A = BAR.A;
Here is how the query will execute:
- ACT opens a cursor on the query.
- The queen activates Parallel Cursors and passes the query
SELECT * FROM FOO, BAR where FOO.A = BAR.A;
to the workers.
- Each worker then computes the entire equi-join as dictated by the FOO.A = BAR.A constraint.
- The queen fetches results from workers in batches of 100 rows, until a limit of 1000 is reached.
- ACT fetches results from the queen in batches of 100 rows, until a limit of 1000 is reached.