One of possible use cases that reproduces the memory leakage listed below:
set timestamp= unix_timestamp('2000-01-01 00:00:00');
create or replace table t1 (x int) with system versioning
partition by system_time interval 1 hour auto
partitions 3;
create table t2 (x int);
create trigger tr after insert on t2 for each row update t1 set x= 11;
create or replace procedure sp2() insert into t2 values (5);
set timestamp= unix_timestamp('2000-01-01 04:00:00');
call sp2;
set timestamp= unix_timestamp('2000-01-01 13:00:00');
call sp2; # <<=== Memory leak happens there. In case MariaDB server is built
with the option -DWITH_PROTECT_STATEMENT_MEMROOT,
the second execution would hit assert failure.
The reason of leaking a memory is that once a new partition be created
the table should be closed and re-opened. It results in calling the function
extend_table_list() that indirectly invokes the function sp_add_used_routine()
to add routines implicitly used by the statement that makes a new memory
allocation.
To fix it, don't remove routines and tables the statement implicitly depends
on when a table being closed for subsequent re-opening.
In cmake -DWITH_UBSAN=ON builds with clang but not with GCC,
-fsanitize=undefined will flag several runtime errors on
function pointer mismatch related to the lock-free hash table LF_HASH.
Let us use matching function signatures and remove function pointer
casts in order to avoid potential bugs due to undefined behaviour.
These errors could be caught at compilation time by
-Wcast-function-type-strict, which is available starting with clang-16,
but not available in any version of GCC as of now. The old GCC flag
-Wcast-function-type is enabled as part of -Wextra, but it specifically
does not catch these errors.
Reviewed by: Vladislav Vaintroub
The patch for MDEV-31340 fixed the following bugs:
MDEV-33084 LASTVAL(t1) and LASTVAL(T1) do not work well with lower-case-table-names=0
MDEV-33085 Tables T1 and t1 do not work well with ENGINE=CSV and lower-case-table-names=0
MDEV-33086 SHOW OPEN TABLES IN DB1 -- is case insensitive with lower-case-table-names=0
MDEV-33088 Cannot create triggers in the database `MYSQL`
MDEV-33103 LOCK TABLE t1 AS t2 -- alias is not case sensitive with lower-case-table-names=0
MDEV-33108 TABLE_STATISTICS and INDEX_STATISTICS are case insensitive with lower-case-table-names=0
MDEV-33109 DROP DATABASE MYSQL -- does not drop SP with lower-case-table-names=0
MDEV-33110 HANDLER commands are case insensitive with lower-case-table-names=0
MDEV-33119 User is case insensitive in INFORMATION_SCHEMA.VIEWS
MDEV-33120 System log table names are case insensitive with lower-cast-table-names=0
Backporting the fixes from 11.5 to 10.5
Some fixes related to commit f838b2d799 and
Rows_log_event::do_apply_event() and Update_rows_log_event::do_exec_row()
for system-versioned tables were provided by Nikita Malyavin.
This was required by test versioning.rpl,trx_id,row.
In case there is a view that queried from a stored routine or
a prepared statement and this temporary table is dropped between
executions of SP/PS, then it leads to hitting an assertion
at the SELECT_LEX::fix_prepare_information. The fired assertion
was added by the commit 85f2e4f8e8
(MDEV-32466: Potential memory leak on executing of create view statement).
Firing of this assertion means memory leaking on execution of SP/PS.
Moreover, if the added assert be commented out, different result sets
can be produced by the statement SELECT * FROM the hidden table.
Both hitting the assertion and different result sets have the same root
cause. This cause is usage of temporary table's metadata after the table
itself has been dropped. To fix the issue, reload the cache of stored
routines. To do it cache of stored routines is reset at the end of
execution of the function dispatch_command(). Next time any stored routine
be called it will be loaded from the table mysql.proc. This happens inside
the method Sp_handler::sp_cache_routine where loading of a stored routine
is performed in case it missed in cache. Loading is performed unconditionally
while previously it was controlled by the parameter lookup_only. By that
reason the signature of the method Sroutine_hash_entry::sp_cache_routine
was changed by removing unused parameter lookup_only.
Clearing of sp caches affects the test main.lock_sync since it forces
opening and locking the table mysql.proc but the test assumes that each
statement locks its tables once during its execution. To keep this invariant
the debug sync points with names "before_lock_tables_takes_lock" and
"after_lock_tables_takes_lock" are not activated on handling the table
mysql.proc
This will makes it easier to find out what replication workers are
doing and what they are waiting for.
Things changed in processlist:
- Slave_SQL time was not consistent. Now time for state "Slave has
read all relay log; waiting for more updates" shows how long it has
waited for getting the next event.
- Slave_worker threads did often show "Closing tables" for a long
time. Now the state is reverted to the previous state after
"Closing tables" is done.
- Commit and Rollback states where not shown for replication (and some
other threads). Now Commit and Rollback states are always shown and
the state is reverted to previous state when the Commit/Rollback
have finished.
Code changes:
- Added thd->set_time_for_next_stage() for parallel replication when
when starting to wait for prior transactions to commit, group commit,
and FTWRL and for free space in thread pool.
Before we reset the time only after the above events.
- Moved THD_STAGE_INFO(stage_rollback) and THD_STAGE_INFO(stage_commit)
from sql_parse.cc to transaction.cc to ensure this is done for
all commits and not only 'normal connection queries'.
Test case changes:
- close_thread_tables() reverting stage to previous stage caused the
counter in performance_schema to be increased. In many case it is
the 'sql/starting' stage that was effected.
- We only change to "Commit" stage if there is a need for a commit.
This caused some "Commit" stages to disapper from perfschema reports.
TODO in 11.#:
- Slave_IO always showes "Waiting for master to send event" and the time is
from SLAVE START. We should in 11.# change this to be the time since
reading the last event.
This patch fixes the issue with passing the DEFAULT or IGNORE values to
positional parameters for some kind of SQL statements to be executed
as prepared statements.
The main idea of the patch is to associate an actual value being passed
by the USING clause with the positional parameter represented by
the Item_param class. Such association must be performed on execution of
UPDATE statement in PS/SP mode. Other corner cases that results in
server crash is on handling CREATE TABLE when positional parameter
placed after the DEFAULT clause or CALL statement and passing either
the value DEFAULT or IGNORE as an actual value for the positional parameter.
This case is fixed by checking whether an error is set in diagnostics
area at the function pack_vcols() on return from the function pack_expression()
Like all IF NOT EXISTS syntax, a Note should be generated.
The original commit of Seqeuences cleared the IF NOT EXISTS part
in the sql/sql_yacc.yy with lex->create_info.init(). Without this
bit set there was no way it could do anything other than error.
To remedy this removal, the sql_yacc.yy components have been
minimised as they where all set at the beginning of the ALTER.
This way the opt_if_not_exists correctly set the IF_EXISTS flag.
In MDEV-13005 (bb4dd70e7c) the error code changed, requiring
ER_UNKNOWN_SEQUENCES to be handled in the function
No_such_table_error_handler::handle_condition.
Crash was caused by referencing a null pointer on getting
the number of the nesting levels of the set function for the current
select_lex at the method Item_field::fix_fields.
The current select for processing is taken from Name_resolution_context
that filled in at the function set_new_item_local_context() and
where initialization of the data member Name_resolution_context
was mistakenly removed by the commit
d6ee351bbb
(Revert "MDEV-24454 Crash at change_item_tree")
To fix the issue, correct initialization of data member
Name_resolution_context::select_lex
that was removed by the commit d6ee351bbb
is restored.
This patch is actually follow-up for the task
MDEV-23902: MariaDB crash on calling function
to use correct query arena for a statement. In case invocation of
a function is in progress use its call arena, else use current
query arena that can be either a statement or a regular query arena.
Add a debug-only field MDL_context::lock_warrant. This field can be set
to the MDL context different from the one the current execution is done in.
The lock warrantor has to hold an MDL for at least a duration of a table
lifetime.
This is needed in the subsequent commit so that the shared MDL acquired by
the InnoDB purge_coordinator_task can be shared by purge_worker_task
that access index records that include virtual columns.
Reviewed by: Vladislav Vaintroub
The MDEV-29693 conflict resolution is from Monty, as well as is
a bug fix where ANALYZE TABLE wrongly built histograms for
single-column PRIMARY KEY.
Also includes a fix for safe_malloc error reporting.
Other things:
- Copied main.log_slow from 10.4 to avoid mtr issue
Disabled test:
- spider/bugfix.mdev_27239 because we started to get
+Error 1429 Unable to connect to foreign data source: localhost
-Error 1158 Got an error reading communication packets
- main.delayed
- Bug#54332 Deadlock with two connections doing LOCK TABLE+INSERT DELAYED
This part is disabled for now as it fails randomly with different
warnings/errors (no corruption).
The warning is given in case of table not found or if there is a lock
timeout. The warning is needed as in case of a lock timeout then the
persistent table stats are going to be wrong.
At the moment we cannot support
wsrep_forced_binlog_format=[MIXED|STATEMENT]
during CREATE TABLE AS SELECT.
Statement will use ROW instead and give
a warning.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
In case a table accessed by a PS/SP is dropped after the first execution of
PS/SP and a view created with the same name as a table just dropped then
the second execution of PS/SP leads to allocation of a memory on SP/PS
memory root already marked as read only on first execution.
For example, the following test case:
CREATE TABLE t1 (a INT);
PREPARE stmt FROM "INSERT INTO t1 VALUES (1)";
EXECUTE stmt;
DROP TABLE t1;
CREATE VIEW t1 S SELECT 1;
--error ER_NON_INSERTABLE_TABLE
EXECUTE stmt; # (*)
DROP VIEW t1;
will hit assert on running the statement 'EXECUTE stmt' marked with (*)
when allocation of a memory be performed on parsing the view.
Memory allocation is requested inside the function mysql_make_view
when a view definition being parsed. In order to avoid an assertion
failure, call of the function mysql_make_view() must be moved after
invocation of the function check_and_update_table_version().
It will result in re-preparing the whole PS statement or current
SP instruction that will free currently allocated items and reset
read_only flag for the memory root.
Moved call of the function check_and_update_table_version() just
before the place where the function extend_table_list() is invoked
in order to avoid allocation of memory on a PS/SP memory root
marked as read only. It happens by the reason that the function
extend_table_list() invokes sp_add_used_routine() to add a trigger
created for the table in time frame between execution the statement
EXECUTE `stmt_id` .
For example, the following test case
create table t1 (a int);
prepare stmt from "insert into t1 (a) value (1)";
execute stmt;
create trigger t1_bi before insert on t1 for each row
set @message= new.a;
execute stmt; # (*)
adds the trigger t1_bi to a list of used routines that involves
allocation of a memory on PS memory root that has been already marked
as read only on first run of the statement 'execute stmt'.
In result, when the statement marked with (*) is executed it results in
assert hit.
To fix the issue call the function check_and_update_table_version()
before invocation of extend_table_list() to force re-compilation of
PS/SP that resets read-only flag of its memory root.
This commits enables reloading of engine-independent statistics
without flushing the table from table definition cache.
This is achieved by allowing multiple version of the
TABLE_STATISTICS_CB object and having independent pointers to it in
TABLE and TABLE_SHARE. The TABLE_STATISTICS_CB object have reference
pointers and are freed when no one is pointing to it anymore.
TABLE's TABLE_STATISTICS_CB pointer is updated to use the
TABLE_SHARE's pointer when read_statistics_for_tables() is called at
the beginning of a query.
Main changes:
- read_statistics_for_table() will allocate an new TABLE_STATISTICS_CB
object.
- All get_stat_values() functions has a new parameter that tells
where collected data should be stored. get_stat_values() are not
using the table_field object anymore to store data.
- All get_stat_values() functions returns 1 if they found any
data in the statistics tables.
Other things:
- Fixed INSERT DELAYED to not read statistics tables.
- Removed Statistics_state from TABLE_STATISTICS_CB as this is not
needed anymore as wer are not changing TABLE_SHARE->stats_cb while
calculating or loading statistics.
- Store values used with store_from_statistical_minmax_field() in
TABLE_STATISTICS_CB::mem_root. This allowed me to remove the function
delete_stat_values_for_table_share().
- Field_blob::store_from_statistical_minmax_field() is implemented
but is not normally used as we do not yet support EIS statistics
for blobs. For example Field_blob::update_min() and
Field_blob::update_max() are not implemented.
Note that the function can be called if there is an concurrent
"ALTER TABLE MODIFY field BLOB" running because of a bug in
ALTER TABLE where it deletes entries from column_stats
before it has an exclusive lock on the table.
- Use result of field->val_str(&val) as a pointer to the result
instead of val (safetly fix).
- Allocate memory for collected statistics in THD::mem_root, not in
in TABLE::mem_root. This could cause the TABLE object to grow if a
ANALYZE TABLE was run many times on the same table.
This was done in allocate_statistics_for_table(),
create_min_max_statistical_fields_for_table() and
create_min_max_statistical_fields_for_table_share().
- Store in TABLE_STATISTICS_CB::stats_available which statistics was
found in the statistics tables.
- Removed index_table from class Index_prefix_calc as it was not used.
- Added TABLE_SHARE::LOCK_statistics to ensure we don't load EITS
in parallel. First thread will load it, others will reuse the
loaded data.
- Eliminate read_histograms_for_table(). The loading happens within
read_statistics_for_tables() if histograms are needed.
One downside is that if we have read statistics without histograms
before and someone requires histograms, we have to read all statistics
again (once) from the statistics tables.
A smaller downside is the need to call alloc_root() for each
individual histogram. Before we could allocate all the space for
histograms with a single alloc_root.
- Fixed bug in MyISAM and Aria where they did not properly notice
that table had changed after analyze table. This was not a problem
before this patch as then the MyISAM and Aria tables where flushed
as part of ANALYZE table which did hide this issue.
- Fixed a bug in ANALYZE table where table->records could be seen as 0
in collect_statistics_for_table(). The effect of this unlikely bug
was that a full table scan could be done even if
analyze_sample_percentage was not set to 1.
- Changed multiple mallocs in a row to use multi_alloc_root().
- Added a mutex protection in update_statistics_for_table() to ensure
that several tables are not updating the statistics at the same time.
Some of the changes in sql_statistics.cc are based on a patch from
Oleg Smirnov <olernov@gmail.com>
Co-authored-by: Oleg Smirnov <olernov@gmail.com>
Co-authored-by: Vicentiu Ciorbaru <cvicentiu@gmail.com>
Reviewer: Sergei Petrunia <sergey@mariadb.com>
Before this patch, the code in Item_field::print() used
this convention (described in sql_explain.h:ExplainDataStructureLifetime):
- By default, the table that Item_field refers to is accessible.
- ANALYZE and SHOW {EXPLAIN|ANALYZE} may print Items after some
temporary tables have been dropped. They use
QT_DONT_ACCESS_TMP_TABLES flag. When it is ON, Item_field::print
will not access the table it refers to, if it is a temp.table
The bug was that EXPLAIN statement also may compute subqueries (depending
on subquery context and @@expensive_subquery_limit setting). After the
computation, the subquery calls JOIN::cleanup(true) which drops some of
its temporary tables. Calling Item_field::print() that refer to such table
will cause an access to free'd memory.
In this patch, we take into account that query optimization can compute
a subquery and discard its temporary tables. Item_field::print() now
assumes that any temporary table might have already been dropped.
This means QT_DONT_ACCESS_TMP_TABLES flag is not needed - we imply it is
always present.
But we also make one exception: derived tables are not freed in
JOIN::cleanup() call. They are freed later in close_thread_tables(),
at the same time when regular tables are closed.
Because of that, Item_field::print may assume that temp.tables
representing derived tables are available.
Initial patch by: Rex Jonston
Reviewed by: Monty <monty@mariadb.org>
The assertion was to make sure we don't do vers_set_hist_part() for
SELECT (or any non-DML). But actually we must do it if SELECT calls
some function that does DML. Patch moves the assertion to non-routines
only.
