- 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.
* rename all debugging related command-line options
and variables to start from "debug-", and made them all
OFF by default.
* replace "MySQL" with "MariaDB" in error messages
* "Cast ... converted ... integer to it's ... complement"
is now a note, not a warning
* @@query_cache_strip_comments now has a session scope,
not global.
- 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.
in EXPLAIN as select_type==MATERIALIZED.
Before, we had select_type==SUBQUERY and it was difficult to tell materialized
subqueries from uncorrelated scalar-context subqueries.
- Make EXPLAIN display "Start temporary" at the start of the fanout (it used to display
at the first table whose rowid gets into temp. table which is not that useful for
the user)
- Updated test results (all checked)
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.
- in make_join_select(), use the correct condition to check whether the current table is a SJM nest (the previous
condition used to be correct before, but then sj-materialization temp table creation was moved to happen before
make_join_select was called)
- 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.
- Make subquery_types_allow_materialization() detect a case where
create_tmp_table() would create a blob column which would make it
impossible to use materialization
Non-semi-join materialization worked because it detected that this case
and felt back to use IN->EXISTS. Semi-join Materialization cannot easily
fallback, so we have to detect this case early.
- 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.
The function matching_cond should take into account that
there may be always false constant conjunctive conditions
that has not been evaluated yet,for example, conjunctive
conditions with non-correlated subqueries.
- 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.
- JOIN::prepare would have set JOIN::table_count to incorrect value (bad merge of MWL 106)
- optimize_keyuse() would use table-bit as table number
(the change in optimize_keyuse is also the reason for query plan changes. Not
expected to have much effect because only handles cases of no index statistics)
- st_select_lex::register_dependency_item() ignored the fact that some of the
selects on the dependency paths could have been merged to their parents (because they
were mergeable VIEWs)
- Undo the incorrect fix in Item_subselect::recalc_used_tables(): do not call
fix_after_pullout() for Item_subselect::Ref_to_outside members.
- Update test results
- Fix a problem with PS:
= convert_subq_to_sj() should not save where to prep_where or on_expr to prep_on_expr.
= After an unmerged subquery predicate has been pulled, it should call fix_after_pullout() for
outer_refs.
- Unify EXPLAIN printout for <subqueryN> tables with regular tables
- Update test results for <subqueryN> tables:
s/unique_key/distinct_key/g
s/1.0/100.0/ for "filtered" column
- Change "SUBQUERY#n" to "<subquery{n}>" in EXPLAIN output. We need to it to be
lowercase so that EXPLAIN results do not differ in case between systems with
case-sensitive and case-insensitive filesystems.
- Remove garbage comments, add better comments.
- 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.
