- Fix st_select_lex::set_explain_type() to allow producing exactly the
same EXPLAINs as it did before. SHOW EXPLAIN output may produce
select_type=SIMPLE instead or select_type=PRIMARY or vice versa (which
is ok because values of select_type weren't self-consistent in this
regard to begin with)
First code
- "Asynchronous procedure call" system
- new THD::check_killed() that serves APC request is called from within most important loops
- EXPLAIN code is now able to generate EXPLAIN output on-the-fly [incomplete]
Parts that are still missing:
- put THD::check_killed() call into every loop where we could spend significant amount of time
- Make sure EXPLAIN code works for group-by queries that replace JOIN::join_tab with make_simple_join()
and other such cases.
- User interface: what error code to use, where to get timeout settings from, etc.
When merging a view / derived table the function SELECT_LEX::merge_subquery
incorrectly updated the list SELECT_LEX::leaf_tables. Erroneously it
appended the leaf_tables list of the merged object L and then removed the
reference to the merged object T from the SELECT_LEX::leaf_tables list.
A correct implementation should insert the list L into the
SELECT_LEX::leaf_tables list in place of the element of the list that
refers to T.
The bug could lead to wrong results or even crashes for queries with
nested outer joins over views / derived tables.
SET STATEMENT.
Server built with debug asserts, without debug crashes if a user tries
to run a stored procedure that constains query with subquery that include
either LIMIT or LIMIT OFFSET clauses.
The problem was that Item::fix_fields() was not called for the items
representing LIMIT or OFFSET clauses.
The solution is to call Item::fix_fields() right before evaluation in
st_select_lex_unit::set_limit().
mysql-test/r/sp.result:
Added testcase result for bug#12621017. Updated testcase result for
bug 11918.
mysql-test/t/sp.test:
Added testcase for bug#12621017. Addressed review comments for Bug 11918
(added tests for use LIMIT at stored function).
sql/item.h:
Addressed review comments for Bug 11918.
sql/share/errmsg-utf8.txt:
Addressed review comments for Bug 11918.
sql/sp_head.cc:
Addressed review comments for Bug 11918.
sql/sql_lex.cc:
Added call fix_fields() for item just before its evaluation.
sql/sql_yacc.yy:
Addressed review comments for Bug 11918.
SET STATEMENT.
Server built with debug asserts, without debug crashes if a user tries
to run a stored procedure that constains query with subquery that include
either LIMIT or LIMIT OFFSET clauses.
The problem was that Item::fix_fields() was not called for the items
representing LIMIT or OFFSET clauses.
The solution is to call Item::fix_fields() right before evaluation in
st_select_lex_unit::set_limit().
There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.
mysql-test/r/sp.result:
test case
mysql-test/t/sp.test:
test case
sql/sql_base.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_class.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_class.h:
THD::used_tables is replaced with LEX::used_tables
sql/sql_insert.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_lex.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_lex.h:
THD::used_tables is replaced with LEX::used_tables
sql/sql_prepare.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_select.cc:
THD::used_tables is replaced with LEX::used_tables
There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.
The problem was that optimizer removes some outer references (it they are
constant for example) and the list of outer items built during prepare phase is
not actual during execution phase when we need it as the cache parameters.
First solution was use pointer on pointer on outer reference Item and
initialize temporary table on demand. This solved most problem except case
when optimiser also reduce Item which contains outer references ('OR' in
this bug test suite).
The solution is to build the list of outer reference items on execution
phase (after optimization) on demand (just before temporary table creation)
by walking Item tree and finding outer references among Item_ident
(Item_field/Item_ref) and Item_sum items.
Removed depends_on list (because it is not neede any mnore for the cache, in the place where it was used it replaced with upper_refs).
Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references (or other expression parameters in future).
mysql-test/r/subselect_cache.result:
A new test added.
mysql-test/r/subselect_scache.result:
Changes in creating the cache and its paremeters order or adding arguments of aggregate function (which is a parameter also, but this has no influence on the result).
mysql-test/t/subselect_cache.test:
Added a new test.
sql/item.cc:
depends_on removed.
Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
Item_cache_wrapper collect parameters befor initialization of its cache.
sql/item.h:
depends_on removed.
Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
sql/item_cmpfunc.cc:
depends_on removed.
Added processor (collect_outer_ref_processor) to collect outer references.
sql/item_cmpfunc.h:
Added processor (collect_outer_ref_processor) to collect outer references.
sql/item_subselect.cc:
depends_on removed.
Added processor get_cache_parameters() method to collect outer references.
sql/item_subselect.h:
depends_on removed.
Added processor get_cache_parameters() method to collect outer references.
sql/item_sum.cc:
Added processor (collect_outer_ref_processor) method to collect outer references.
sql/item_sum.h:
Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
sql/opt_range.cc:
depends_on removed.
sql/sql_base.cc:
depends_on removed.
sql/sql_class.h:
New iterator added.
sql/sql_expression_cache.cc:
Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done).
sql/sql_expression_cache.h:
Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done).
sql/sql_lex.cc:
depends_on removed.
sql/sql_lex.h:
depends_on removed.
sql/sql_list.h:
Added add_unique method to add only unique elements to the list.
sql/sql_select.cc:
Support of new Item list added.
sql/sql_select.h:
Support of new Item list added.
Also:
1. simplified the code of the function mysql_derived_merge_for_insert.
2. moved merge of views/dt for multi-update/delete to the prepare stage.
3. the list of the references to the candidates for semi-join now is
allocated in the statement memory.
The attribute not_null_tables could be calculated incorrectly in the
function SELECT_LEX::update_used_tables for queries over views
with row items in the WHERE clause. It happened because no
implementation of the virtual callback function eval_not_null_tables
was provided for the class Item_row.
Also slightly optimized the code calculating the value of the maybe_null
flag for tables in the function SELECT_LEX::update_used_tables.
The bitmap of used tables must be evaluated for the select list of every
materialized derived table / view and saved in a dedicated field.
This is also applied to materialized subqueries.
We must allocate a larger ref_pointer_array. We failed to account for extra
items allocated here:
#0 find_order_in_list
uint el= all_fields.elements;
all_fields.push_front(order_item); /* Add new field to field list. */
ref_pointer_array[el]= order_item;
order->item= ref_pointer_array + el;
#1 setup_order
#2 setup_without_group
#3 JOIN::prepare
mysql-test/r/order_by.result:
New test case.
mysql-test/r/union.result:
New test case.
mysql-test/t/order_by.test:
New test case.
mysql-test/t/union.test:
New test case.
sql/sql_lex.cc:
find_order_in_list() may need some extra space, so multiply og_num by two.
sql/sql_union.cc:
For UNION, the 'n_sum_items' are accumulated in the "global_parameters" select_lex.
This number must be propagated to setup_ref_array()
When preparing a 'fake_select_lex' we need to use global_parameters->order_list
rather than fake_select_lex->order_list (see comments inside st_select_lex_unit::cleanup)
We must allocate a larger ref_pointer_array. We failed to account for extra
items allocated here:
#0 find_order_in_list
uint el= all_fields.elements;
all_fields.push_front(order_item); /* Add new field to field list. */
ref_pointer_array[el]= order_item;
order->item= ref_pointer_array + el;
#1 setup_order
#2 setup_without_group
#3 JOIN::prepare
Missing initialization of the bitmap not_null_tables_cache to 0
in the function Item_func::eval_not_null_tables caused this bug.
This function is called indirectly from the function
SELECT_LEX::update_used_tables after merging mergeable views and
derived tables into the main query. The leaf tables of resulting
query may change their bitmap numbers after this merge. That's why
the not_null_tables_cache bitmaps must be updated. Due to the bug
mentioned above the result of the re-evaluation of the
not_null_tables_cache turned out to be incorrect in some cases.
This could trigger an invalid conversion of outer joins into
inner joins leading to invalid query result sets.
Also removed an implicit conversion from int to bool in the function
SELECT_LEX::update_used_tables.
client/mysql_upgrade.c:
missing DBUG_RETURN
client/mysqladmin.cc:
client plugin memory wasn't freed
client/mysqlcheck.c:
client plugin memory, defaults, a result set, a command-line option value were not freed.
missing DBUG_RETURN.
client/mysqldump.c:
client plugin memory wasn't freed
client/mysqlslap.c:
client plugin memory wasn't freed
client/mysqltest.cc:
hopeless. cannot be fixed.
mysql-test/valgrind.supp:
Bug#56666 is now fixed.
mysys/array.c:
really, don't allocate if the caller didn't ask to.
mysys/my_init.c:
safemalloc checks must be done at the very end
mysys/my_thr_init.c:
not needed anymore
sql-common/client.c:
memory leak
sql/log.cc:
log_file was not closed, memory leak.
sql/mysqld.cc:
fix bug#56666 (causing many P_S related memory leaks).
close_active_mi() not called for --bootstrap, memory leak.
sql/sql_lex.cc:
redo Lex->mi handling
sql/sql_lex.h:
redo Lex->mi handling
sql/sql_plugin.cc:
plugins having PLUGIN_VAR_MEMALLOC string variables have this variables allocated in every THD.
The memory was freed in ~THD but only if plugin was still active. If plugin was unloaded the
variable was not found and the memory was lost. By loading and unloading plugins an arbitrary
amount of memory can be lost.
sql/sql_repl.cc:
redo Lex->mi handling
sql/sql_yacc.yy:
completely wrong handling of Lex->mi - run-time memory leak, by repeating the statement
arbitrary amount of memory can be lost.
Lex->mi.repl_ignore_server_ids_opt was allocated when parsing CHANGE MASTER,
and freed after executing the statement. if parser failed on syntax (or another)
error the statement was never executed. Lex->mi was simply bzero-ed for the next
CHANGE MASTER statement.
sql/table.cc:
didn't compile
storage/perfschema/pfs_lock.h:
Bug#56666 is fixed
The value of THD::used tables should be re-evaluated after merges
of views and derived tables into the main query.
Now it's done in the function SELECT_LEX::update_used_tables.
The re-evaluation of the 'used_table' bitmaps for the items
in HAVING, GROUP BY and ORDER BY clauses has been added as well.
The offending query returns a wrong result set because the optimizer
erroneously eliminated the where condition evaluated it to TRUE.
The cause of this wrong transformation was that the flag maybe_null
for an inner table of the outer join was not set to TRUE after the
table had replaced the wrapping view.
Now the function SELECT_LEX::update_used_tables resets the value
of the maybe_null flag for each leaf table of the query after all
merges of views have been done.
- 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.
Changed the code that processing of multi-updates and multi-deletes
with multitable views at the prepare stage.
A proper solution would be: never to perform any transformations of views
before and at the prepare stage. Yet it would require re-engineering
of the code that checks privileges and updatability of views.
Ultimately this re-engineering has to be done to provide a clean solution
for INSERT/UPDATE/DELETE statements that use views.
Fixed a valgrind problem in the function TABLE::use_index.
Uncommented the failing test cases.
Commented out the failing test case from parts.partition_repair_myisam.test.
The test case has to be changed to bear the same semantics as before mwl106.
mysql-test/r/subselect4.result:
Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.
mysql-test/t/subselect4.test:
Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.
