in the function best_access_path revealed another bug: currently
table scans on NULL keys used for NOT IN subqueries cannot work
together with employment of join caches for inner tables of these
subqueries. Otherwise the result can be wrong as it could be seen
with the result of the test case constructed for bug #37894
in the file subselect3_jcl6.result.
of the 5.3 code line after a merge with 5.2 on 2010-10-28
in order not to allow the cost to access a joined table to be equal
to 0 ever.
Expanded data sets for many test cases to get the same execution plans
as before.
- convert_subq_to_jtbm() didn't check that subuqery optimization was successful. If it wasn't (in this
example because of @@max_join_size violation), it would proceed further and eventually crash when
trying to execute the un-optimized subquery.
- 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.
The problem: in an uncorrelated subquery, JOIN execution code may make
irreversible cleanups after it has been executed (because the subquery
won't be executed again). In particular, JTBM nests and their injected
IN-equalities will be invalidated (the materialized table will be dropped
and TABLE structure freed).
Solution: don't walk into Item_subselect if represents an uncorrelated
subselect that has already been executed. The idea is that the subselect
will not be executed again (calling Item_subselect_xxx::val_int() will fetch
the cached value), so it should not matter what is inside the subselect.
- 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.
on Windows, kill <connection> can and almost always will return client error 2013 ("Lost connection...") on the killed connection,
On the server side, if connection is "sleeping" KILL will close the socket, thus socket error on client is expected.
Analysis:
The crash is a result of the same cause as all similar
bugs (lp:827416, lp:718763, lp:778413, lp:806943,
lp:611690). The general pattern is that some optimization
requires the evaluation of some condition (e.g. the WHERE
clause), and this condition contains a subquery, such that
the subquery itself requires a temporary table for its
execution. During the subquery execution the original
tables in the FROM clause are replaced by the temporary
table needed for the final GROUP or ORDER operation. All
this happens during optimization of the outer query. Later
when EXPLAIN is run for the subquery, explain attempts to
print the name of the tables in the FROM clause, but it
finds there a temporary table without a corresponding
TABLE_LIST object. The attempt to print the name of a
NULL table list results in a crash.
Solution:
This patch extends the fix to bug lp:702301, and dissalows
constant substitution of aggregate functions if the filter
condition used to check MIN/MAX keys is an expensive condition.
Threat ER_CONNECTION_KILLED same as ER_SERVER_SHUTDOWN in replication (to get rid of a possible warning in error log)
sql/slave.cc:
Threat ER_CONNECTION_KILLED same as ER_SERVER_SHUTDOWN
One can set @@global.max_user_connections to -1 to block anyone, except SUPER user, to login.
If max_user_connection is 0, one can't change it without a restart (needed to get user connections counting to work correctly)
mysql-test/r/system_mysql_db.result:
Changed max_user_connections to handle negative numbers.
mysql-test/r/user_limits-2.result:
New test case that one can't change max_user_connection if it was 0
mysql-test/r/user_limits.result:
Fixed wrong error messages.
mysql-test/r/variables.result:
Store / restore max_user_connections (needed as there is now a --master.opt file that changes it)
mysql-test/t/subselect_mat_cost-master.opt:
Enable slow query log (as this test found some errors in slow query logging)
mysql-test/t/user_limits-2.test:
New test case that one can't change max_user_connection if it was 0
mysql-test/t/user_limits-master.opt:
Set max_user_connections (as one can't change it if it was 0)
mysql-test/t/user_limits.test:
Test max_user_connections -1
mysql-test/t/variables-master.opt:
Set max_user_connections (as one can't change it if it was 0)
mysql-test/t/variables.test:
Set/restore max_user_connections
scripts/Makefile.am:
Add a text message to mysql_fix_privilege_tables.sql that it's automaticly generated
scripts/mysql_system_tables.sql:
Change max_user_connections to signed
scripts/mysql_system_tables_fix.sql:
Change max_user_connections to signed
sql/item_func.cc:
Change SHOW_INT to be signed.
(Needed for max_user_connections and it's probably a bug that it was not originally signed)
sql/log.cc:
Remove some code that was not needed (All these variables are reset at start of query)
sql/mysql_priv.h:
Made max_user_connections signed.
Added max_user_connections_checking
sql/mysqld.cc:
Added max_user_connections_checking so that we know if max_user_connections was 0 at startup
(Which means that we will not do connection counting for accounts that don't have user resource limits)
Set thd->start_utime at same time as thr_create_utime. (Before start_utime could be < thr_create_utime which lead to wrong query counting)
sql/set_var.cc:
Don't allow one to change 'max_user_connections' if it was 0 at startup.
sql/sql_acl.cc:
Change user_connection counting to be negative.
sql/sql_connect.cc:
If max_user_connections is < 0 then only SUPER user can login.
Fixed wrong variable names for error messages.
Fixed wrong initial value for questions.
Set thd->start_utime and thd->thr_create_utime at startup. Needed to get time_out_user_resource_limits() to work.
sql/sql_show.cc:
SHOW_INT is now negative
sql/sql_yacc.yy:
Support negative values for MAX_USER_CONNECTIONS
sql/structs.h:
Make user connect counting work with signed numbers.
Reset 'examined_rows_count' in union to not count same rows twice
mysql-test/r/subselect_mat_cost.result:
Test also slow query logging
mysql-test/t/subselect_mat_cost.test:
Test also slow query logging
sql/sql_union.cc:
Reset 'examined_rows_count' in union to not count same rows twice
- If USER is given, all threads for that user is signaled
- If SOFT is used then the KILL will not be sent to the handler. This can be used to not interrupt critical things in the handler like 'REPAIR'.
Internally added more kill signals. This gives us more information of why a query/connection was killed.
- KILL_SERVER is used when server is going down. In this case the users gets ER_SHUTDOWN as the reason connection was killed.
- Changed signals to number in correct order, which makes it easier to test how the signal should affect the code.
- New error message ER_CONNECTION_KILLED if connection was killed by 'KILL CONNECTION'. Before we got error ER_SHUTDOWN.
Changed names of not used parameters KILL_QUERY & KILL_CONNCTION to mysql_kill() to not conflict with defines in the server
include/mysql.h.pp:
Updated file
include/mysql_com.h:
Changed names of not used parameters KILL_QUERY & KILL_CONNCTION to mysql_kill() to not conflict with defines in the server
mysql-test/r/kill.result:
Added test of KILL USER
mysql-test/suite/rpl/r/rpl_stm_000001.result:
Updated error code
mysql-test/suite/rpl/t/rpl_stm_000001.test:
Updated error codes
mysql-test/t/flush_read_lock_kill.test:
Updated error codes
mysql-test/t/kill.test:
Added test of KILL USER
plugin/handler_socket/handlersocket/database.cpp:
Removed THD:: from KILL
sql/debug_sync.cc:
Removed THD:: from KILL
sql/event_scheduler.cc:
Removed THD:: from KILL
sql/filesort.cc:
Removed THD:: from KILL
sql/ha_ndbcluster_binlog.cc:
Removed THD:: from KILL
sql/handler.cc:
Removed THD:: from KILL
Simplify code.
sql/lex.h:
Added new keywords HARD | SOFT
sql/log.cc:
Removed THD:: from KILL
Added testing of new error ER_CONNECTION_KILLED
sql/log_event.cc:
Removed THD:: from KILL
Added testing of new error ER_CONNECTION_KILLED
sql/mysql_priv.h:
Added new prototypes
sql/mysqld.cc:
Removed THD:: from KILL
Use KILL_SERVER_HARD signal on shutdown.
sql/scheduler.cc:
Removed THD:: from KILL
Simplify test if connection should be killed
sql/share/errmsg.txt:
New error message ER_CONNECTION_KILLED
sql/slave.cc:
Removed THD:: from KILL
sql/sp_head.cc:
Removed THD:: from KILL
sql/sql_base.cc:
Removed THD:: from KILL
sql/sql_cache.cc:
Removed THD:: from KILL
sql/sql_class.cc:
Removed THD:: from KILL
Added killed_errno()
Only signal kill to storage engine if HARD bit is set.
sql/sql_class.h:
Move KILL options out from THD to make them easier to use in sql_yacc.yy
sql/sql_connect.cc:
Removed THD:: from KILL
sql/sql_delete.cc:
Removed THD:: from KILL
sql/sql_error.cc:
Removed THD:: from KILL
sql/sql_insert.cc:
Removed THD:: from KILL
Simplifed testing if thread is killed.
sql/sql_lex.h:
Added kill options to st_lex
sql/sql_load.cc:
Removed THD:: from KILL
sql/sql_parse.cc:
Added kill options to st_lex
Simplifed and optimzed testing of thd->killed at end of query
Added support for KILL USER
Extended sql_kill() to allow use of more kill signals.
sql/sql_repl.cc:
Removed THD:: from KILL
sql/sql_show.cc:
Removed THD:: from KILL
Simplied testing if query/connection was killed
sql/sql_table.cc:
Removed THD:: from KILL
sql/sql_update.cc:
Removed THD:: from KILL
sql/sql_yacc.yy:
Added support for new KILL syntax: KILL [HARD|SOFT] [CONNECTION|QUERY] [ID | USER user_name]
storage/archive/ha_archive.cc:
Simplify compilation
storage/maria/ha_maria.cc:
Removed THD:: from KILL
- Provide fix_after_pullout() function for Item_in_optimizer and other Item_XXX classes (basically, all of them
that have eval_not_null_tables, which means they have special rules for calculating not_null_tables_cache value)
- The problem was that Item_direct_view_ref and its embedded Item_field were getting incorrect
value of item->used_tables() after fix_fields() in the second and subsequent EXECUTE.
- Made relevant fixes in Item_field::fix_fields() and find_field_in_tables(), so that the
Item_field gets the correct attributes.
- If convert_join_subqueries_to_semijoins() decides to wrap Item_in_subselect in Item_in_optimizer,
it should do so in prep_on_expr/prep_where, too, as long as they are present.
There seems to be two possibilities of how we arrive in this function:
- prep_on_expr/prep_where==NULL, and will be set later by simplify_joins()
- prep_on_expr/prep_where!=NULL, and it is a copy_and_or_structure()-made copy of on_expr/where.
the latter can happen for some (but not all!) nested joins. This bug was that we didn't handle this case.
- Mrr_ordered_index_reader::interrupt_read() and resume_read() should
save/restore not just index lookup tuple, but entire index tuple.
Key parts that are not used for index lookup can be still used in
pushed index condition. Failure to save/restore will cause the index
condition to be evaluated over the wrong values.
Give proper error to client on shutdown.
configure.in:
Increased version number
mysql-test/mysql-test-run.pl:
Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/r/variables.result:
Remember original value of log_warnings
mysql-test/suite/rpl/r/rpl_idempotency.result:
Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/suite/rpl/t/rpl_idempotency.test:
Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/t/variables.test:
Remember original value of log_warnings
sql/mysqld.cc:
Give proper error to close_connection() on shutdown
storage/maria/ha_maria.cc:
Added missing DBUG_RETURN
Give more information when finding an error in a MyISAM table.
When killing system thread, use KILL_SYSTEM_THREAD instead of KILL_CONNECTION to make it easier to ignore the signal in sensitive context (like auto-repair)
Added new kill level: KILL_SERVER that will in the future to be used to signal killed by shutdown.
Add more warnings about killed connections when warning level > 3
include/myisamchk.h:
Added counting of printed info/notes
mysys/mf_iocache.c:
Remove duplicate assignment
sql/handler.cc:
Added test of KILL_SERVER
sql/log.cc:
Ignore new 'kill' error ER_NEW_ABORTING_CONNECTION when requesting query error code.
sql/mysqld.cc:
Add more warnings for killed connections when warning level > 3
sql/scheduler.cc:
Added checks for new kill signals
sql/slave.cc:
Ignore new kill signal ER_NEW_ABORTING_CONNECTION
sql/sp_head.cc:
Fixed assignment to bool
Added testing of new kill signals
sql/sql_base.cc:
Use KILL_SYSTEM_THREAD to auto-kill system threads
sql/sql_class.cc:
Add more warnings for killed connections when warning level > 3
thd_killed() now ignores KILL_BAD_DATA and THD::KILL_SYSTEM_THREAD as these should not abort sensitive operations.
sql/sql_class.h:
Added KILL_SYSTEM_THREAD and KILL_SERVER
sql/sql_connect.cc:
Added handling of KILL_SERVER
sql/sql_insert.cc:
Use KILL_SYSTEM_THREAD to auto-kill system threads
Added handling of KILL_SERVER
sql/sql_parse.cc:
Add more warnings for killed connections when warning level > 3
Added checking that thd->abort_on_warning is reset at end of query.
sql/sql_show.cc:
Update condition for when a query is 'killed'
storage/myisam/ha_myisam.cc:
Added counting of info/notes printed
storage/myisam/mi_check.c:
Always print an an error if we find data errors when checking/repairing a MyISAM table.
When a repair was killed, don't retry repair.
Added assert if sort_get_next_record() returned an error without an error message.
Removed nonsence check "if (sort_param->read_cache.error < 0)" in repair.
storage/myisam/myisamchk.c:
Added counting of notes printed
storage/pbxt/src/thread_xt.cc:
Better error message.
