The upper 1M limit for max_prepared_stmt_count was set over 10 years
ago. It doesn't suite current hardware and a sysbench oltp_read_write
test with 512 threads will hit this limit.
If translation table present when we materialize the derived table then
change it to point to the materialized table.
Added debug info to see really what happens with what derived.
Make SELECT <columns> FROM I_S.TABLES behave identically independently
from whether <columns> require opening the table in engine or
<columns> can be filled with only opening the frm.
In particular, fill_schema_table_from_frm() should not silently skip
frms with unknown engine, but should fill the I_S.TABLES row
with NULLs just like fill_schema_table_by_open() does.
Also, implement MDEV-11027 a little differently from 5.5 and 10.0:
recv_apply_hashed_log_recs(): Change the return type back to void
(DB_SUCCESS was always returned).
Report progress also via systemd using sd_notifyf().
As the function Item_subselect::fix_fields does it the function
Item_subselect::update_used_tables must ignore UNCACHEABLE_EXPLAIN
when deciding whether the subquery item should be considered as a
constant item.
In original code, sometimes one got an automatic DEFAULT value in some cases, in other cases not.
For example:
create table t1 (a int primary key) - No default
create table t2 (a int, primary key(a)) - DEFAULT 0
create table t1 SELECT .... - Default for all fields, even if they where defined as NOT NULL
ALTER TABLE ... MODIFY could sometimes add an unexpected DEFAULT value.
The patch is quite big because we had some many test cases that used
CREATE ... SELECT or CREATE ... (...PRIMARY KEY(xxx)) which doesn't have an automatic DEFAULT anymore.
Other things:
- Removed warnings from InnoDB when waiting from semaphore (got this when testing things with --big)
Added MAX_STATEMENT_TIME user variable to automaticly kill queries after a given time limit has expired.
- Added timer functions based on pthread_cond_timedwait
- Added kill_handlerton() to signal storage engines about kill/timeout
- Added support for GRANT ... MAX_STATEMENT_TIME=#
- Copy max_statement_time to current user, if stored in mysql.user
- Added status variable max_statement_time_exceeded
- Added KILL_TIMEOUT
- Removed digest hash from performance schema tests as they change all the time.
- Updated test results that changed because of the new user variables or new fields in mysql.user
This functionallity is inspired by work done by Davi Arnaut at twitter.
Test case is copied from Davi's work.
Documentation can be found at
https://kb.askmonty.org/en/how-to-limittimeout-queries/
mysql-test/r/mysqld--help.result:
Updated for new help message
mysql-test/suite/perfschema/r/all_instances.result:
Added new mutex
mysql-test/suite/sys_vars/r/max_statement_time_basic.result:
Added testing of max_statement_time
mysql-test/suite/sys_vars/t/max_statement_time_basic.test:
Added testing of max_statement_time
mysql-test/t/max_statement_time.test:
Added testing of max_statement_time
mysys/CMakeLists.txt:
Added thr_timer
mysys/my_init.c:
mysys/mysys_priv.h:
Added new mutex and condition variables
Added new mutex and condition variables
mysys/thr_timer.c:
Added timer functions based on pthread_cond_timedwait()
This can be compiled with HAVE_TIMER_CREATE to benchmark agains timer_create()/timer_settime()
sql/lex.h:
Added MAX_STATEMENT_TIME
sql/log_event.cc:
Safety fix (timeout should be threated as an interrupted query)
sql/mysqld.cc:
Added support for timers
Added status variable max_statement_time_exceeded
sql/share/errmsg-utf8.txt:
Added ER_QUERY_TIMEOUT
sql/signal_handler.cc:
Added support for KILL_TIMEOUT
sql/sql_acl.cc:
Added support for GRANT ... MAX_STATEMENT_TIME=#
Copy max_statement_time to current user
sql/sql_class.cc:
Added timer functionality to THD.
Added thd_kill_timeout()
sql/sql_class.h:
Added timer functionality to THD.
Added KILL_TIMEOUT
Added max_statement_time variable in similar manner as long_query_time was done.
sql/sql_connect.cc:
Added handling of max_statement_time_exceeded
sql/sql_parse.cc:
Added starting and stopping timers for queries.
sql/sql_show.cc:
Added max_statement_time_exceeded for user/connects status in MariaDB 10.0
sql/sql_yacc.yy:
Added support for GRANT ... MAX_STATEMENT_TIME=# syntax, to be enabled in 10.0
sql/structs.h:
Added max_statement_time user resource
sql/sys_vars.cc:
Added max_statement_time variables
mysql-test/suite/roles/create_and_drop_role_invalid_user_table.test
Removed test as we require all fields in mysql.user table.
scripts/mysql_system_tables.sql
scripts/mysql_system_tables_data.sql
scripts/mysql_system_tables_fix.sql
Updated mysql.user with new max_statement_time field
mysql-test/r/acl_roles_show_grants.result:
one can do SHOW GRANTS for himself
mysql-test/t/acl_roles_set_role-table-column-priv.test:
correct error message
mysql-test/t/acl_roles_show_grants.test:
one can SHOW GRANTS for himself
sql/sql_acl.cc:
bugfixing:
* don't assign with && - it can shortcut and the second assignment won't be executed
* correct the test in check_grant_all_columns() - want_access should not be modified
*
sql/sql_cmd.h.OTHER:
add new commands at the end
sql/sql_db.cc:
don't call acl_get() if all privileges are already satisfied
(crashes when run with --skip-grants, because acl data stuctures aren't initialized)
sql/sql_parse.cc:
* test for current_user in get_current_user()
* map explicitly specified user@host to current_user
two tests still fail:
main.innodb_icp and main.range_vs_index_merge_innodb
call records_in_range() with both range ends being open
(which triggers an assert)
Analysis:
The fix for lp:944706 introduces early subquery optimization.
While a subquery is being optimized some of its predicates may be
removed. In the test case, the EXISTS subquery is constant, and is
evaluated to TRUE. As a result the whole OR is TRUE, and thus the
correlated condition "b = alias1.b" is optimized away. The subquery
becomes non-correlated.
The subquery cache is designed to work only for correlated subqueries.
If constant subquery optimization is disallowed, then the constant
subquery is not evaluated, the subquery remains correlated, and its
execution is cached. As a result execution is fast.
However, when the constant subquery was optimized away, it was neither
cached by the subquery cache, nor it was cached by the internal subquery
caching. The latter was due to the fact that the subquery still appeared
as correlated to the subselect_XYZ_engine::exec methods, and they
re-executed the subquery on each call to Item_subselect::exec.
Solution:
The solution is to update the correlated status of the subquery after it has
been optimized. This status consists of:
- st_select_lex::is_correlated
- Item_subselect::is_correlated
- SELECT_LEX::uncacheable
- SELECT_LEX_UNIT::uncacheable
The status is updated by st_select_lex::update_correlated_cache(), and its
caller st_select_lex::optimize_unflattened_subqueries. The solution relies
on the fact that the optimizer already called
st_select_lex::update_used_tables() for each subquery. This allows to
efficiently update the correlated status of each subquery without walking
the whole subquery tree.
Notice that his patch is an improvement over MySQL 5.6 and older, where
subqueries are not pre-optimized, and the above analysis is not possible.
