- Corrected a wrong result that was recorded by the MySQL fix for BUG#39069.
- Removed Item_func_isnull::cached_value and all the logic around this custom-made
caching of the NULL result because MWL#89 optimizes subqueries before the outer
query is being executed, and this cache cannot be made easily to work for all
kinds of Items (specifically Item_sum_sum, but others too).
libmysqld/Makefile.am:
The new file added.
mysql-test/r/index_merge_myisam.result:
subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
The subquery cache tests added.
mysql-test/r/subselect3.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
The subquery cache tests added.
mysql-test/t/subselect3.test:
Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
The new file added.
sql/Makefile.am:
The new files added.
sql/item.cc:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
Subquery cache added.
sql/item_cmpfunc.h:
Subquery cache added.
sql/item_subselect.cc:
Subquery cache added.
sql/item_subselect.h:
Subquery cache added.
sql/item_sum.cc:
Registration of subquery parameters added.
sql/mysql_priv.h:
subquery_cache optimization option added.
sql/mysqld.cc:
subquery_cache optimization option added.
sql/opt_range.cc:
Fix due to subquery cache.
sql/opt_subselect.cc:
Parameters of the function cahnged.
sql/procedure.h:
.h file guard added.
sql/sql_base.cc:
Registration of subquery parameters added.
sql/sql_class.cc:
Option to allow add indeces to temporary table.
sql/sql_class.h:
Item iterators added.
Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
Expression cache for caching subqueries added.
sql/sql_lex.cc:
Registration of subquery parameters added.
sql/sql_lex.h:
Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
Subquery cache added.
sql/sql_select.h:
Subquery cache added.
sql/sql_union.cc:
A new parameter to the function added.
sql/sql_update.cc:
A new parameter to the function added.
sql/table.cc:
Procedures to manage temporarty tables index added.
sql/table.h:
Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
.h file guard added.
storage/myisam/ha_myisam.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
- 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.
semi-join, where the the REF buffer format was mistaken to be in
record format instead of key format. The error was that the null
byte for all fields of the record was in the front of the buffer,
and not before each field data.
Bug#48623: Multiple subqueries are optimized incorrectly
The function setup_semijoin_dups_elimination() has a major loop that
goes through every table in the JOIN object. Usually, there is a normal
"plus one" increment in the for loop that implements this, but each semijoin
nest is treated as one entity and there is another increment that skips past
the semijoin nest to the next table in the JOIN object. However, when
combining these two increments, the next joined table is skipped, and if that
happens to be the start of another semijoin nest, the correct processing
for that nest will not be carried out.
mysql-test/r/subselect_sj.result:
Added test results for bug#48623
mysql-test/r/subselect_sj_jcl6.result:
Added test results for bug#48623
mysql-test/t/subselect_sj.test:
Added test case for bug#48623
sql/opt_subselect.cc:
Omitted the "plus one" increment in the for loop, added "plus one"
in the remaining switch case, fixed coding style issue in remaining
increment operations.
Fix two problems:
1. Let optimize_semijoin_nests() reset sj_nest->sjmat_info irrespectively
of value of optimizer_flag. We need this in case somebody has turned optimization
off between reexecutions of the same statement.
2. Do not pull out constant tables out of semi-join nests. The problem is that pullout
operation is not undoable, and if a table is constant because it is 1/0-row table it
may cease to be constant on the next execution. Note that tables that are constant
because of possible eq_ref(const) access will still be pulled out as they are
considered functionally-dependent.
Bug#48213 Materialized subselect crashes if using GEOMETRY type
The problem occurred because during semi-join a materialized table
was created which contained a GEOMETRY column, which is a specialized
BLOB column. This caused an segmentation fault because such tables will
have extra columns, and the semi-join code was not prepared for that.
The solution is to disable materialization when Blob/Geometry columns would
need to be materialized. Blob columns cannot be used for index look-up
anyway, so it does not makes sense to use materialization.
This fix implies that it is detected earlier that subquery materialization
can not be used. The result of that is that in->exist optimization may
be performed for such queries. Hence, extended query plans for such
queries had to be updated.
mysql-test/r/subselect_mat.result:
Update extended query plan for subqueries that cannot use materialization
due to Blobs.
mysql-test/r/subselect_sj.result:
Updated result file.
mysql-test/r/subselect_sj_jcl6.result:
Update result file.
mysql-test/t/subselect_sj.test:
Add test case for Bug#48213 that verifies that semi-join works when subquery select list contain Blob columns. Also verify that materialization is not
used.
sql/opt_subselect.cc:
Disable materialization for semi-join/subqueries when the subquery select list
contain Blob columns.
BUG#50019: Wrong result for IN-subquery with materialization
- Fix equality substitution in presense of semi-join materialization, lookup and scan variants
(started off from fix by Evgen Potemkin, then modified it to work in all cases)
This patch does three things:
- It adds the possibility to force the execution of top-level [NOT] IN
subquery predicates via the IN=>EXISTS transformation. This is done by
setting both optimizer switches partial_match_rowid_merge and
partial_match_table_scan to "off".
- It adjusts all test cases where the complete optimizer_switch is
selected because now we have two more switches.
- For those test cases where the plan changes because of the new available
strategies, we switch off both partial match strategies in order to
force the "old" IN=>EXISTS strategy. This is done because most of these
test cases specifically test bugs in this strategy.
sql/opt_subselect.cc:
Adds the possibility to force the execution of top-level [NOT] IN
subquery predicates via the IN=>EXISTS transformation. This is done by
setting both optimizer switches partial_match_rowid_merge and
partial_match_table_scan to "off".
- The problem was that DuplicateWeedout strategy setup code wasn't aware of the
fact that join buffering will be used and applied optimization that doesn't work
together with join buffering. Fixed by making DuplicateWeedout setup code to have
a pessimistic check about whether there is a chance that join buffering will be
used.
- Make JOIN_CACHE_BKA::init() correctly process Copy_field elements that denote saving
current rowids in the join buffer.
mysql-test/r/subselect_sj2.result:
Update test results
mysql-test/r/subselect_sj2_jcl6.result:
Update test results
mysql-test/r/subselect_sj_jcl6.result:
Testcase
mysql-test/t/subselect_sj2.test:
Update test results
mysql-test/t/subselect_sj_jcl6.test:
Testcase
sql/opt_subselect.cc:
- The problem was that DuplicateWeedout strategy setup code wasn't aware of the
fact that join buffering will be used and applied optimization that doesn't work
together with join buffering. Fixed by making DuplicateWeedout setup code to have
a pessimistic check about whether there is a chance that join buffering will be
used.
sql/sql_join_cache.cc:
Make JOIN_CACHE_BKA::init() correctly process Copy_field elements that denote saving current rowids in the join buffer.
sql/sql_select.cc:
Added a question note
This patch implements correct NULL semantics for materialized subquery execution.
The implementation has the following properties and main limitations:
- It passes all query result tests, but fails a number of EXPLAIN tests because of
changed plans.
- The EXPLAIN output for partial matching is not decided yet.
- It works only when all necessary indexes fit into main memory. Notice that these
are not the general B-tree/Hash indexes, but instead much more compact ones,
therefore this limitation may not be a problem in many practical cases.
- It doesn't contain specialized tests.
- In several places the implementation uses methods that are modified copies of
other similar methods. These cases need to be refactored to avoid code duplication.
- Add a test if the predicate is top-level just before deciding on partial matching.
If it is top-level, use a more efficient exec method (index lookup).
- Add sorting of indexes according to their selectivity. The code is almost there.
- Needs more comments, and to sync existing ones with the implementation.
sql/item_cmpfunc.h:
Expose the Arg_comparator of a comparison predicate. This makes it possible to
directly get the comparison result {-1,0,1}, which is not possible through the
val_XXX() methods which "fold" such results into a boolean.
sql/item_subselect.cc:
The core of the implementation of MWL#68.
sql/item_subselect.h:
The core of the implementation of MWL#68.
sql/opt_subselect.cc:
Removed the limitation for materialized subquery execution that it is applicable only
for top-level predicates.
sql/sql_class.cc:
New class select_materialize_with_stats that collects data statistics about
the data being inserted into the target table.
sql/sql_class.h:
New class select_materialize_with_stats that collects data statistics about
the data being inserted into the target table.
sql/sql_select.cc:
- more complete initialization of the TABLE object of a temp table.
- call setup_subquery_materialization at one more exit point.
