The original code was there to favor index search over table scan.
This is not needed anymore as the cost calculations for table scans
and index lookups are now more exact.
This feature adds the functionality of ignorability for indexes.
Indexes are not ignored be default.
To control index ignorability explicitly for a new index,
use IGNORE or NOT IGNORE as part of the index definition for
CREATE TABLE, CREATE INDEX, or ALTER TABLE.
Primary keys (explicit or implicit) cannot be made ignorable.
The table INFORMATION_SCHEMA.STATISTICS get a new column named IGNORED that
would store whether an index needs to be ignored or not.
- There is no reason to collect EITS statistics
- The test is sporadically failing on some platforms. I believe the
issue is in InnoDB. Let's rule out EITS code as a possible source
of the issue.
