New read-only system variables (set at startup, need --log-error):
* log_error_file_buffer_size: error log buffer size, default 0 (off)
* log_error_file_rotate_size: rotate the error log above this size,
default 1073741824
* log_error_file_rotations: number of rotated files kept, default 0
Changes:
* Write the error log through the logger service, which batches writes
in an in-memory buffer, when log_error_file_buffer_size is set.
* print_buffer_to_file() uses one static buffer, allocated on first use
(MAX_LOG_BUFFER_SIZE+1), grown as needed and freed at shutdown.
* vprint_msg_to_log() writes lines longer than 1024 bytes in full, up
to 1 MB.
* Galera messages use the same error log path. Debug messages are
written only if wsrep_debug is set.
* Add mtr tests for the three variables, buffered logging, rotation and
long lines.
Assisted-by: https://mariadb.org/governance/governance-ai-policy/
Removed type aliases and macros defined in my_global.h from my_bit.h,
making it possible to include it in plugins or external code without
pulling in my_global.h
Or max_statement_time limit or MAX_DEPTH.
Correct interuptability and depth checking of:
* JSON_CONTAINS
* JSON_CONTAINS_PATH
* JSON_EXISTS
* JSON_EXTRACT
* JSON_KEYS
* ST_GeomFromGeoJSON
Populate in the json library the killed as a specific
error message. As the json library has a killed_ptr
is approprate it handles it.
As json_report_error now processes the killed there's
no need of thd->check_killed().
Verified that the path after every json_scan_next, the
location of checking the killed_ptr, reports errors
correctly.
Backport to 10.6 without JSON_OVERLAPS
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_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.
Clang upstream bug https://github.com/llvm/llvm-project/issues/173210
shows that a "int x=x" construct will in the intermediate representation
have code to read from x. With this generated sanitizer=undefined and
static analyzers will all see the uninitialized read and write.
Because clang has a stronger implementation of following paths to
uninitialized variables, "#define UNINIT_VAR(x) x" is the which
is what our release binaries use is the ideal path for this compiler.
Clang based compilers with error during compilation if any
uninitialized behaviour is detected at compile time because of
0c80ddb519.
Corrects MDEV-36542 - 6fd57f478f.
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>
When calling buf_flush_ahead() with furious=false, the function
updates the async target buf_flush_async_lsn and, if necessary notifies
the page cleaner thread to start flushing more eagerly, to avoid
a long stall later when checkpoint will be required.
When many threads call buf_flush_ahead() with furious=false, if
the update of buf_flush_async_lsn is gated inside
buf_pool.flush_list_mutex, this can cause significant contention,
just to deliver the new buf_flush_async_lsn value and a potential
notification to the page cleaner thread.
This commit enables, for the non furious case, lock-free update
of buf_flush_async_lsn and lock-free check of the page cleaner idle
flag, to avoid the contention on buf_pool.flush_list_mutex.
The lock is acquired by the CAS-loop winner thread and only
after the page cleaner is observed idle.
The cleaner clears buf_flush_async_lsn via CAS, so a concurrent
lock-free bump is preserved across the clear.
Since the reads are not protected by the mutex, there is a chance that
the decision to not signal the page cleaner thread is wrong.
In the worst case though, under sustained redo-log pressure,
eventually a wakeup signal will be delivered to the page cleaner thread
anyway, so the risk of a long stall is limited.
Similar reasoning applies to the possibly wrong decision taken by the
page cleaner thread to go to idle: eventually it will be woken up.
scripts/fill_help_tables.sql from
https://github.com/mariadb-corporation/mariadb-docs/ as of
3fb208fcdfed06beb52ef9e305017de2387ff012
Other URL changes are taken from the HTTP redirection URL
from the old KB.
Some test cases where impacted:
* ps_missed_cmds{,_bin_prot} - used a topic_id of 0 that is
now used, used MAX_INT instead.
* range_notembedded used the help data as a test case. As its not
a stable table data, replaces with static data. Test case valid
by ensuring the ANALYZE EXPLAIN and optimizer trace had the same
structure. Also valided the MDEV-24739/MDEV-25069 bug fixes from
where the test case originaled, when reverted, exhibited the
previous behavour before the bug fixes.
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.
..passed as argument 2, which is declared to never be null
(dynstr_append_mem).
dynstr_append_mem, uses memcpy to append to the string which in the glibc
library is declared to not take null string as the src. Defensively we
declare dynstr_append_mem to not take a null argument too.
mariadb-test, to prevent it calling dynstr_append_mem with a null
mtr variable value, one that hasn't been initialized, we return an
error if the value is null. The result of this is the $6 in the test
case is never assigned a value and would error.
With this resolved, strchr, if the string isn't found, a null pointer is
returned. UBSAN will complain both about incrementing a pointer beyond
the boundary, and also incrementing if it is null.
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
Lock LOCK_plugin only when the variable is a plugin variable.
Lock LOCK_global_system_variables only when the variable is a
global-only variable or a plugin variable.
Also fix lockless session value for Sys_var_multi_source_ulonglong.
This saves 54 calls to pthread_mutex_lock when constructing the
initial OK packet.
The added testcases do not show the lock savings. They are there to
improve coverage for the MDEV-31609 feature, in light of bugs like
MDEV-39207 and MDEV-39217.
Remove the unscoped #pragma GCC diagnostic ignored
"-Wdeprecated-declarations" from include/violite.h and replace all
sprintf/vsprintf calls with snprintf/vsnprintf across the codebase.
Where possible, pass actual buffer sizes as function parameters
instead of using hardcoded constants or recomputing strlen().
Notable API changes:
- get_date(): added to_len parameter for buffer size
- nice_time(), end_timer() in client/mysql.cc: added buff_size
- generate_new_name(): added name_size parameter
- calc_md5(): added buffer_size parameter (fixes off-by-one)
- MD5_HASH_TO_STRING macro: added _size parameter
- Added MYSQL_UDF_MAX_RESULT_LENGTH constant in mysql_com.h
Also fixed a pre-existing bug in sql/rpl_mi.cc where the ellipsis
"..." was written to the wrong buffer (dbuff instead of buff).
Vendored code is excluded: extra/readline, extra/wolfssl,
wsrep-lib, libmariadb, storage/mroonga/vendor, zlib.
Remove function checks that are guaranteed by C89/C99 standards to
reduce the excessive time spent during CMake configuration step. Also,
clean up related compatibility code.
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.
Replaced macros with optimized inline functions, that use memcpy
instead of unaligned access (translates to single instruction
on architectures we support). Used compiler byteswap intrinsics
where appropriate.
Removed byte_order_generic.h as well as Intel specific headers
byte_order_generic_{x86|x86_64}.h
Added some casts to places where intNstore writes into "const char*".
my_large_virtual_alloc(): If large page allocation fails, clear
my_use_large_pages. Outside large page allocation (and IBM AIX),
invoke mmap(2) with PROT_NONE so that no page table entries will
have to be allocated. Also, fix the error reporting.
my_virtual_mem_commit(): Do not set the Linux specific flag MAP_POPULATE
because it would introduce a performance regression on startup.
There is a better, system-wide way to disable the overcommit:
sudo sysctl vm.overcommit_memory=2
HAVE_UNACCESSIBLE_AFTER_MEM_DECOMMIT: Remove. We will always make
the virtual memory unaccessible, so that the operating system
can deallocate the page table entries.
buf_pool_t::create(): Skip the my_virtual_mem_commit() on AIX only.
buf_pool_t::page_guess(): Unconditionally check if the pointer is
within the currently allocated buffer pool.
innodb_buffer_pool_size_max: On 64-bit systems other than IBM AIX,
we will default to 8 TiB.
On 32-bit systems, we retain the default innodb_buffer_pool_size_max=0,
that is, by default, SET GLOBAL innodb_buffer_pool_size=... will be
unable to increase from the initial value.
There is no functional change to the startup logic that adjusts
innodb_buffer_pool_size_max to be at least innodb_buffer_pool_size
rounded up to the extent size (2 MiB on 32-bit, 8 MiB on 64-bit).
Problem:
=========
An assertion failure occurs in InnoDB during consecutive
ALTER TABLE operations using the COPY algorithm. The crash
happens during the table rename phase because the
source table (dict_table_t::n_ref_count) is non-zero, despite
the thread holding an exclusive Metadata Lock (MDL).
Reason:
========
When ALTER IGNORE TABLE is executed via the COPY algorithm,
it generates undo logs for every row inserted into the
intermediate table (e.g., #sql-alter-...). The background Purge
Thread, responsible for cleaning up these undo logs, attempts
to take an MDL on the table to prevent the table from
being dropped while in use.
Race condition:
==================
First ALTER: Creates #sql-alter-, copies data, and renames it to t1.
Purge Activation: The Purge thread picks up the undo logs from step 1.
It takes an MDL on the temporary name (#sql-alter-) and increments
the table's n_ref_count.
Identity Shift: InnoDB renames the physical table object to t1, but
the Purge thread still holds a reference to this object.
Second ALTER: Starts a new copy process. When it attempts to rename
the "new" t1 to a backup name, it checks if n_ref_count == 0.
Because the Purge thread is still "pinning" the object to
clean up logs from the first ALTER, the count is > 0,
triggering the assertion failure.
Solution:
========
ALTER IGNORE TABLE needs row-level undo logging to easily
roll back the last inserted row in case of duplicate key errors.
By discarding the last undo log record after inserting each row,
purge will not process any log records generated by
ALTER IGNORE TABLE, preventing unexpected access from the purge
subsystem during subsequent DDL operations.
Make skip_alter_undo (1-bit) to (2-bit enum)
to support different ALTER operation modes:
- NO_UNDO (0): Normal mode with standard undo logging
- SKIP_UNDO (1): ALTER mode that skips undo logging
- IGNORE_UNDO (2): ALTER IGNORE mode that rewrites undo blocks
trx_undo_report_row_operation(): Add ALTER IGNORE undo
rewriting logic. Store old undo record info before writing
new records for IGNORE_UNDO mode. Reset undo top_offset
to maintain only latest insert undo
row_ins_clust_index_entry_low(): Prevent ALTER IGNORE from
using bulk insert optimization. since it requires to write
undo log for each row operation that's incompatible with
existing bulk operation.
On IA-32 and AMD64 (x86-64) CPU implementations, the latency of the
PAUSE instruction (REPZ NOP that was repurposed from a no-operation
on the Intel Pentium 4) can vary a lot, and we may adjust the
my_cpu_relax_multiplier accordingly. Let us display the value of
that variable on startup if --log-warnings=3 or larger was specified.
Microsoft Windows is available for multiple instruction set architectures.
Therefore, we had better not assume that defined(_WIN32) implies the
availability of a PAUSE instruction.
Reviewed by: Sergey Vojtovich
- Scoped partial optimization for MDEV-21543 improving
PAD SPACE collations for multibyte character sets in
HA_KEYTYPE_VARTEXT1.
- This keeps the old behavior for other cases until
MDEV-38712 is resolved.
- Benchmark: see zulip topic in the PR description
- Results:
- ~3.1% lower wall-clock time
- ~2.1% fewer CPU cycles
- ~0.5% fewer retired instructions
- ~0.7% fewer branch mispredictions
