- Let JTBM optimization code handle the case where the subquery is degenerate and doesn't have a
join query plan. Regular materialization would fall back to IN->EXISTS for such cases. Semi-Join
materialization does not have such option, instead we introduce and use "constant JTBM join tabs".
- Do a "more thorough" cleanup of SJ-Materialization join tab in JOIN_TAB::cleanup. The bug
was due to the fact that JOIN_TAB::cleanup() may be called multiple times for the same tab
if the join has grouping.
- Part 1 of the fix: for semi-join merged subqueries, calling child_join->optimize() until we're done with all
PS-lifetime optimizations in the parent.
If the optimizer switch 'semijoin_with_cache' is set to 'off' then
join cache cannot be used to join inner tables of a semijoin.
Also fixed a bug in the function check_join_cache_usage() that led
to wrong output of the EXPLAIN commands for some test cases.
- The problem was that JOIN::save/restore_query_plan() did not save/restore parts of
the query plan that are located inside SJ_MATERIALIZATION_INFO structures. This could
cause parts of one plan to be used with another, which led get_best_combination() to
constructing non-sensical join plans (and crash).
Fixed by saving/restoring SJM parts of the query plans.
- check_and_do_in_subquery_rewrites() will not set SUBS_MATERIALIZATION flag when it
records that the subquery predicate is to be converted into semi-join.
If convert_join_subqueries_to_semijoins() later decides not to convert to semi-join,
let it set SUBS_MATERIALIZATION flag, if appropriate.
- are_tables_local() failed to recognize the fact that OUTER_REF_TABLE_BIT is ok
for SJ-Materialization. This caused zero-length ref access to be constructed, which
led to an assert.
- Item_in_subselect::inject_in_to_exists_cond() should not call
((Item_cond*)join->conds)->argument_list()->concat(join->cond_equal->current_level)
as that makes two lists share their tail, and the cond_equal list
will end up containing non-Item_equal objects when substitute_for_best_equal_field()
walks through join->conds and replaces all Item_equal objects with Item_func_eq objects.
- So, instead of using List::concat(), manually copy entries from one list to another.
- setup_sj_materialization() code failed to take into account that it can be that
the first [in join order ordering] table inside semi-join-materialization nest
is also an inner table wrt an outer join (that is embedded in the semi-join).
This can happen when all of the tables that are inside the semi-join but not inside
the outer join are constant.
- Made a trivial to not assume that table's embedding join nest is the semi-join
nest: instead, walk up the outer join nests until we reach the semi-join nest.
Identified all test cases in the MySQL file subquery_mat.inc that are
not present in MariaDB. In total found 8 test cases for the following
MySQL bugs:
* BUG#49630 - not a bug in MariaDB, added test case
* BUG#52538 - not a bug in MariaDB, added test case (checked with VG)
* BUG#53103 - not a bug in MariaDB, added test case
* BUG#54511 - not a bug in MariaDB, added test case
* BUG#56367 - not a bug in MariaDB, added test case
* BUG#59833 - not a bug in MariaDB, added test case
* BUG#11852644 - not a bug in MariaDB, added test case
* BUG#12668294 - not a bug in MariaDB, added test case
All of these MySQL bugs are not present in MariaDB 5.3.
The comparison was based on the following version of
mysql-trunk:
revno: 3350 [merge]
committer: Marko Mäkelä <marko.makela@oracle.com>
branch nick: mysql-trunk
timestamp: Mon 2011-08-08 12:42:09 +0300
message:
Merge mysql-5.5 to mysql-trunk.
- Set the default
- Adjust the testcases so that 'new' tests are run with optimizations turned on.
- Pull out relevant tests from "irrelevant" tests and run them with optimizations on.
- Run range.test and innodb.test with both mrr=on and mrr=off
semijoin=on,firstmatch=on,loosescan=on
to
semijoin=off,firstmatch=off,loosescan=off
Adjust the testcases:
- Modify subselect*.test and join_cache.test so that all tests
use the same execution paths as before (i.e. optimizations that
are being tested are enabled)
- Let all other test files run with the new default settings (i.e.
with new optimizations disabled)
- Copy subquery testcases from these files into t/subselect_extra.test
which will run them with new optimizations enabled.
- Code cleanu.
- Make MWL#90 code require @@optimizer_switch='semijoin=on'
- Update test results with the above
- Fork subselect_mat.test - we want to check both semi-join materialization,
which now has broader scope and non-semijoin materialization.
