A DELETE containing a single table, an index hint, an impossible WHERE
condition, and a window function will take the multi-delete code path
but never initialize tables for deletion, leading to a crash. Such
a statement would never delete rows from the target table. Record in the
multi_delete whether it was ever initialized for execution, and don't
attempt to delete anything if it wasn't initialized.
The index hint forces the single table DELETE to take the multi-table
codepath. Since this case has an impossible WHERE condition, we set
subq_exit_fl which later causes JOIN::optimize_stage2 to skip the
multi-delete table initialization. It's not safe to attempt
initialization when trying to find a "tableless" subquery plan, so
defend against this case with the new multi-delete flag added by
this commit.
This task loads the stats of the tables that are used in a query,
from the trace into the optimizer. This feature is controlled
by optimizer_replay_context, and points to an user defined variable name,
that has the context information.
The stats such as num_of_records present in the table, indexes if present,
their names, along with the average number of records_per_key
with in each index, cost of reading an index are loaded from the trace.
Additionally, stats from range analysis i.e. ranges, and the
corresponding number of records, along with their costs are also
loaded from the trace.
The trace context which is in JSON format is firstly set into the
user defined session variable, and this variable name is set to
optimizer_replay_context system variable.
Later, when a user issues a query, the contents of the json context is
parsed and an in memory representation is built using the class
Optimizer_context_replay. This class is then used by the optimizer
to update and save original values of the tables, indexes, and range stats
in the methods "set_statistics_for_table()" of sql_statistics.cc, and
"check_quick_select()" of opt_range.cc.
After the query gets finished, the statistics that were updated
in the optimizer are restored back to the saved original values.
The entry point for parsing the json structure is in
"mysql_execute_command()" of sql_parse.cc, and similarly exit point
i.e. to restore the saved stats of the optimizer is at the end
of the same method.
Two new warning/error messages are introduced:
ER_JSON_OPTIMIZER_REPLAY_CONTEXT_PARSE_FAILED, and
ER_JSON_OPTIMIZER_REPLAY_CONTEXT_MATCH_FAILED
This feature stores the basic stats of the base tables that are used in
a query, to the optimizer trace. This feature is also controlled by
optimizer_record_context, and is not enabled by default. The stats
such as num_of_records present in the table, indexes if present
then their names, along with the average number of records_per_key
with in each index are dumped to the trace. Additionally, stats from
range analysis of the queries are also dumped into the trace
The approach taken here is to extend the existing function
store_tables_context_in_trace() and add new dump_table_stats_to_trace()
to opt_trace_ddl_info.cc. For storing the range analysis stats into the
trace, they are first recorded in the hash defined in
Optimizer_Stats_Context_Recorder, and is used later while dumping the
stats into the trace from dump_table_stats_to_trace().
Several new tests are also added to opt_trace_store_stats.test
The "is it my own thread" check compared the login user name
(Security_context::user) and ignored the host, so u1@localhost could see
and kill threads of u1@'127.0.0.1'.
Compare the authenticated account instead:
* all comparisons are done in sctx->is_priv_user() now
* change user_matches() to priv_user_matches(), which uses is_priv_user()
* use it in KILL, KILL USER, SHOW PROCESSLIST, I_S.PROCESSLIST,
COM_PROCESS_INFO and SHOW EXPLAIN/ANALYZE FOR.
* all the remaining places use is_priv_user() directly instead
of doing strcmp: SHOW GRANTS, SHOW CREATE PROCEDURE, I_S.VIEWS,
the DEFINER clause, optimizer trace and change_security_context().
Assisted-by: Claude:claude-5-opus
user_var_entry objects and their names have a connection lifetime,
they exist until the connection ends (or is reset), and then they're
all deleted at once. This is exactly the use case for MEM_ROOT,
let's store them there.
Additionally, let's set MY_ROOT_USE_VMEM flag to keep this memroot
off the general heap where user_var_entry values are stored
and where heap buffer overflows can happen.
The latter makes memory allocations for the MEM_ROOT about 10x more
expensive, so let's always start with an empty memroot (= zero overhead
if no user variables are used) and on THD cleanup let's retain one
memroot block (= zero overhead if the next connection takes THD from the
cache and uses user variables up to one block size).
Assisted-By: Claude:claude-4.8-opus
This patch to mysqldump is only merged partially:
commit 666ff1db36
Author: Monty <monty@mariadb.org>
Date: Fri May 15 16:39:35 2026 +0300
MDEV-39519 Change mariadb-dump to use SHOW REPLICA STATUS instead of SHOW SLAVE STATUS
The functionality for --dump-slave cannot be merged as the underlying
functionality was removed in this commit:
commit 21c940d599
Author: ParadoxV5 <paradox.ver5@gmail.com>
Date: Thu Dec 4 21:22:20 2025 -0700
MDEV-37146 mariadb-dump: Replace SHOW SLAVE STATUS usage with information_schema.SLAVE_STATUS
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
On THD::reset, typecast the result of query_start_sec_part() to
tv_usec in a more portable way. Previously, we assumed that the
left hand side was always long-compatible but that isn't the case
on mac.
- Change thd->backup_commit_lock from MDL_request* to MDL_ticket*,
and convert related call sites in handler.cc, log.cc, sql_class.cc,
and xa.cc to use MDL_ACQUIRE_LOCK.
- Convert reload_acl_and_cache() in sql_reload.cc, purge_master_logs()
and reset_master() in sql_repl.cc to MDL_ACQUIRE_LOCK, holding the
ticket in a local MDL_ticket* (these functions used a local
MDL_request originally and should not touch thd->backup_commit_lock).
- Convert acquire_lock() in partition_info.cc to MDL_ACQUIRE_LOCK.
- Add MDL_REQUEST_LIST_ADD() helper for enqueuing lock requests into
MDL_request_list, and convert call sites in sql_base.cc and sp.cc.
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.
GROUP_CONCAT is limited by group_concat_max_len,
but also, as a string function it must respect max_allowed_packet.
Let's introduce THD::gconcat_max_len() helper to simplify checks.
Also:
* make max group_concat_max_len value the same as max max_allowed_packet
* use the same MY_MIN((ulonglong) ..., UINT_MAX32) in
Item_func_json_objectagg as in Item_func_group_concat
* use overflow-safe type for lengths in Item_func_quote
(MAX_MAX_ALLOWED_PACKET is 1G so uint cannot overflow yet, but it's
a fragile assumption)
The json_engine killed_ptr was of type uchar however the enum
in the server is dependant on the architecture. On big-endian
architectures like IBM Z, retreiving a uchar* retreived the
unmodifed part of the THD->kill enum location and was always 0.
As C++11 allows enums to inherit a type, used uint32_t as the base
class of killed_state type in the server and used uint32_t in the
json library.
reload_acl_and_cache required an expression change to avoid
the compile error:
sql/sql_reload.cc:472:24: error: enumerated and non-enumerated
type in conditional expression [-Werror=enum-conversion]
472 | return result || (thd ? thd->killed : 0);
Added the kill_ptr assignment the following functions can be
killed:
* Item_func_json_depth::val_int
* Item_func_json_type::val_str
* Item_func_json_length::val_int
Item_func_json_array_append::val_str, check_killed() only applied
to json_error: label and not return_null.
Item_func_json_overlaps::val_bool ensure check_killed() is called.
Item_func_json_format::val_str(), corresponding to the SQL,
json_compact, json_detailed, json_loose - add debug instrumentation
for the func_json_notembedded test.
MDEV-26726 (fcd345de48) added a json_pause_execution sync point
however the test case used debug_max_statement_time, which doesn't
exist. Fix the sync point name in the test.
The tool is named mariadb-migrate-config-file.
The main purpose of the tool is to change MySQL option
files to work both for MySQL and MariaDB.
There are options to do the changes in the options file inline,
or at-end-of-file. One can also remove or comment unknown options.
The list of supported options is generated compile time from
mariadbd --help. All server options, including compiled plugins, are
supported.
The bulk of the code comes from Väinö.
Monty has updated it with a lot of extra options.
Wlad helped with cmake integration
Other things:
- Fixed a memory leak in sql_plugin.cc
- plugin-load will now in case of errors try to load all given plugins
before aborted
- If silent-startup is used, plugin-load will not give errors for
plugins it cannot load or warnings about plugin marturity level.
- my_rm_tree() will now delete symlinks, not the actual file, if
MY_NOSYMLINK flag is used.
- my_stat() will now give data for symlink if MY_NOSYMLINKS is used.
- Added 'number of lines' option to mysqltest --cat_file
@Authors: Väinö Mäkelä <vaino.makela@iki.fi>,monty@mariadb.com
introduce a dedicated enum type for sql_command_flags
to simplify debugging:
(gdb) p sql_command_flags[SQLCOM_SELECT]
$2 = (CF_REEXECUTION_FRAGILE | CF_CAN_GENERATE_ROW_EVENTS | CF_PREOPEN_TMP_TABLES | CF_CAN_BE_EXPLAINED | CF_OPTIMIZER_TRACE)
The patch introduces the OLD_VALUE() expression to reference the value
of a column before it was updated. The parser is extended to support
RETURNING and OLD_VALUE(), and RETURNING expressions are stored in a
separate returning_list in SELECT_LEX with independent wildcard tracking.
RETURNING is rejected for multi-table UPDATE.
During setup of RETURNING fields, THD::is_setting_returning is used
when resolving fields, particularly for updates through views.
When resolving view fields, Item_direct_view_ref may point to the
view's item_list, losing the information about whether the value
should be old or new. The original item in returning_list still
contains the correct is_old_value_reference flag, which is copied
back to the resolved item.
OLD_VALUE() is implemented by extending Item_field with a new
Item_old_field class. Item_field::set_field() initializes
Field::ptr_old to the corresponding location in record[1],
which stores the old row during UPDATE execution.
When sending result rows, Item_old_field::send() temporarily switches
the field pointer from record[0] (current row) to ptr_old so
OLD_VALUE() returns the value before the update.
The UPDATE execution path is modified to send a result set when
RETURNING is present instead of an OK packet.
MDL_context_owner was introduced in MySQL for gtest unit testing of MDL,
which MariaDB doesn't use. Its virtual methods (enter_cond, exit_cond,
is_killed, get_thd, notify_shared_lock) are not MDL-specific - they are
part of THD and were only encapsulated in MDL_context_owner as a
misleading abstraction.
This is a cleanup that:
- Removes the MDL_context_owner class entirely
- Removes THD's inheritance from MDL_context_owner
- Changes MDL to use THD* directly instead of MDL_context_owner*
- Removes the redundant MDL_context::get_owner() method
- Moves ENTER_COND/EXIT_COND macros to sql_class.h near THD_ENTER_COND
removed:
* DES encryption
* --secure-auth
* --old
* spider table options: bfz, btt, cmd, ctp, cwg, isa, ilm, ios, smd, stc, stl
extended under old-mode:
* YEAR(2), still available when old-mode=2_DIGIT_YEAR
un-deprecated:
* keep_files_on_create, originally (MDEV-23570) the idea was to make it
TRUE and deprecate. It cannot be removed when FALSE, but TRUE breaks
mariabackup.aria_backup where a table is altered from Aria to InnoDB
during a backup, so both t.MAD/t.MAI and t.ibd gets into a backup.
Adding support for cursors on prepared statements.
- SQL Standard way:
DECLARE c CURSOR FOR stmt;
PREPARE stmt FROM 'SELECT ?';
OPEN c USING 1;
- Oracle-style way with SYS_REFCURSOR variables:
DECLARE
c SYS_REFCURSOR;
BEGIN
OPEN c FOR 'SELECT ?' USING 1;
don't create a permanent stack of paths on the heap and in THD.
Do it on the stack like for sql_mode, sctx, abort_on_warning, and
other THD properties that often need to be changed temporarily.
Fix Sql_path constructor.
Definition
==========
Implement the SET PATH statement.
```
SET PATH 'schema1, schema2, schema3';
```
Function
--------
In MariaDB, the SQL-path will also be used to lookup packages in
package routine invocations, so the following script:
SET PATH 'sys';
SELECT UTL_ENCODE.BASE64_DECODE('data');
invokes SYS.UTL_ENCODE.BASE64_DECODE('data'), i.e. the function
BASE64_DECODE() in the packge UTL_ENCODE in the database SYS
(if such package and package routine exist).
MariaDB implementation details
------------------------------
The ticket's requirement stated the grammar should support delimited
identifiers with backticks or double quotes within the string quote,
ie: the single tick. A simple parser was implemented to handle this
requirement in Sql_path::from_text.
Only 16 schemas are supported per session - we do not want too many
schemas in the path anyway since it will impact performance. This also
means that the path cache is a simple static array for easier memory
management.
