PredicatePushdownTest does not properly test for predicate pushdown in all
cases
----------------------------------------------------------------------------------
Key: DERBY-4046
URL: https://issues.apache.org/jira/browse/DERBY-4046
Project: Derby
Issue Type: Bug
Components: Test
Affects Versions: 10.5.0.0
Reporter: Kathey Marsden
In DERBY-3819 Knut commented that the JUnit test PredicatePushdownTest is no
longer properly testing predicate pushdown after conversion.
https://issues.apache.org/jira/browse/DERBY-3819?focusedCommentId=12669371#action_12669371
There is a comment in the test:
// [We]can tell if a predicate has been "pushed" by looking at
// the query plan information for the tables in question:
// if the table has an index on a column that is used as
// part of the pushed predicate, then the optimizer will
// (for these tests) do an Index scan instead of a Table
// scan. If the table does not have such an index then the
// predicate will show up as a "qualifier" for a Table
// scan. In all of these tests T3 and T4 have appropriate
// indexes, so if we push a predicate to either of those
// tables we should see index scans. Neither T1 nor T2 has
// indexes, so if we push a predicate to either of those
// tables we should see a qualifier in the table scan
// information.
So I think that means in the case of index scans our checks are ok, but for
table scans we should also be checking the qualifiers. The join strategy
checks are not really relevant except that hash join prevents predicate
pushdown.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
