This commit updates default memory allocations size used with MEM_ROOT
objects to minimize the number of calls to malloc().
Changes:
- Updated MEM_ROOT block sizes in sql_const.h
- Updated MALLOC_OVERHEAD to also take into account the extra memory
allocated by my_malloc()
- Updated init_alloc_root() to only take MALLOC_OVERHEAD into account as
buffer size, not MALLOC_OVERHEAD + sizeof(USED_MEM).
- Reset mem_root->first_block_usage if and only if first block was used.
- Increase MEM_ROOT buffers sized used by my_load_defaults, plugin_init,
Create_tmp_table, allocate_table_share, TABLE and TABLE_SHARE.
This decreases number of malloc calls during queries.
- Use a small buffer for THD->main_mem_root in THD::THD. This avoids
multiple malloc() call for new connections.
I tried the above changes on a complex select query with 12 tables.
The following shows the number of extra allocations that where used
to increase the size of the MEM_ROOT buffers.
Original code:
- Connection to MariaDB: 9 allocations
- First query run: 146 allocations
- Second query run: 24 allocations
Max memory allocated for thd when using with heap table: 61,262,408
Max memory allocated for thd when using Aria tmp table: 419,464
After changes:
Connection to MariaDB: 0 allocations
- First run: 25 allocations
- Second run: 7 allocations
Max memory allocated for thd when using with heap table: 61,347,424
Max memory allocated for thd when using Aria table: 529,168
The new code uses slightly more memory, but avoids memory fragmentation
and is slightly faster thanks to much fewer calls to malloc().
Reviewed-by: Sergei Golubchik <serg@mariadb.org>
Heap tables are allocated blocks to store rows according to
my_default_record_cache (mapped to the server global variable
read_buffer_size).
This causes performance issues when the record length is big
(> 1000 bytes) and the my_default_record_cache is small.
Changed to instead split the default heap allocation to 1/16 of the
allowed space and not use my_default_record_cache anymore when creating
the heap. The allocation is also aligned to be just under a power of 2.
For some test that I have been running, which was using record length=633,
the speed of the query doubled thanks to this change.
Other things:
- Fixed calculation of max_records passed to hp_create() to take
into account padding between records.
- Updated calculation of memory needed by heap tables. Before we
did not take into account internal structures needed to access rows.
- Changed block sized for memory_table from 1 to 16384 to get less
fragmentation. This also avoids a problem where we need 1K
to manage index and row storage which was not counted for before.
- Moved heap memory usage to a separate test for 32 bit.
- Allocate all data blocks in heap in powers of 2. Change reported
memory usage for heap to reflect this.
Reviewed-by: Sergei Golubchik <serg@mariadb.org>
Partial commit of the greater MDEV-34348 scope.
MDEV-34348: MariaDB is violating clang-16 -Wcast-function-type-strict
Reviewed By:
============
Marko Mäkelä <marko.makela@mariadb.com>
Partial commit of the greater MDEV-34348 scope.
MDEV-34348: MariaDB is violating clang-16 -Wcast-function-type-strict
The functions queue_compare, qsort2_cmp, and qsort_cmp2
all had similar interfaces, and were used interchangable
and unsafely cast to one another.
This patch consolidates the functions all into the
qsort_cmp2 interface.
Reviewed By:
============
Marko Mäkelä <marko.makela@mariadb.com>
The code in best_access_path() uses PREV_BITS(uint, N) to
compute a bitmap of all keyparts: {keypart0, ... keypart{N-1}).
The problem is that PREV_BITS($type, N) macro code can't handle the case
when N=<number of bits in $type).
Also, why use PREV_BITS(uint, ...) for key part map computations when
we could have used PREV_BITS(key_part_map) ?
Fixed both:
- Change PREV_BITS(type, N) to handle any N in [0; n_bits(type)].
- Change PREV_BITS() to use key_part_map when computing key_part_map bitmaps.
This patch extends the timestamp from
2038-01-19 03:14:07.999999 to 2106-02-07 06:28:15.999999
for 64 bit hardware and OS where 'long' is 64 bits.
This is true for 64 bit Linux but not for Windows.
This is done by treating the 32 bit stored int as unsigned instead of
signed. This is safe as MariaDB has never accepted dates before the epoch
(1970).
The benefit of this approach that for normal timestamp the storage is
compatible with earlier version.
However for tables using system versioning we before stored a
timestamp with the year 2038 as the 'max timestamp', which is used to
detect current values. This patch stores the new 2106 year max value
as the max timestamp. This means that old tables using system
versioning needs to be updated with mariadb-upgrade when moving them
to 11.4. That will be done in a separate commit.
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.
Warnings are added to net_server.cc when
global_system_variables.log_warnings >= 4.
When the above condition holds then:
- All communication errors from net_serv.cc is also written to the
error log.
- In case of a of not being able to read or write a packet, a more
detailed error is given.
Other things:
- Added detection of slaves that has hangup to Ack_receiver::run()
- vio_close() is now first marking the socket closed before closing it.
The reason for this is to ensure that the connection that gets a read
error can check if the reason was that the socket was closed.
- Add a new state to vio to be able to detect if vio is acive, shutdown or
closed. This is used to detect if socket is closed by another thread.
- Testing of the new warnings is done in rpl_get_lock.test
- Suppress some of the new warnings in mtr to allow one to run some of
the tests with -mysqld=--log-warnings=4. All test in the 'rpl' suite
can now be run with this option.
- Ensure that global.log_warnings are restored at test end in a way
that allows one to use mtr --mysqld=--log-warnings=4.
Reviewed-by: <serg@mariadb.org>,<brandon.nesterenko@mariadb.com>
This makes it easier to compare different costs and also allows
the optimizer to optimizer different storage engines more reliably.
- Added tests/check_costs.pl, a tool to verify optimizer cost calculations.
- Most engine costs has been found with this program. All steps to
calculate the new costs are documented in Docs/optimizer_costs.txt
- User optimizer_cost variables are given in microseconds (as individual
costs can be very small). Internally they are stored in ms.
- Changed DISK_READ_COST (was DISK_SEEK_BASE_COST) from a hard disk cost
(9 ms) to common SSD cost (400MB/sec).
- Removed cost calculations for hard disks (rotation etc).
- Changed the following handler functions to return IO_AND_CPU_COST.
This makes it easy to apply different cost modifiers in ha_..time()
functions for io and cpu costs.
- scan_time()
- rnd_pos_time() & rnd_pos_call_time()
- keyread_time()
- Enhanched keyread_time() to calculate the full cost of reading of a set
of keys with a given number of ranges and optional number of blocks that
need to be accessed.
- Removed read_time() as keyread_time() + rnd_pos_time() can do the same
thing and more.
- Tuned cost for: heap, myisam, Aria, InnoDB, archive and MyRocks.
Used heap table costs for json_table. The rest are using default engine
costs.
- Added the following new optimizer variables:
- optimizer_disk_read_ratio
- optimizer_disk_read_cost
- optimizer_key_lookup_cost
- optimizer_row_lookup_cost
- optimizer_row_next_find_cost
- optimizer_scan_cost
- Moved all engine specific cost to OPTIMIZER_COSTS structure.
- Changed costs to use 'records_out' instead of 'records_read' when
recalculating costs.
- Split optimizer_costs.h to optimizer_costs.h and optimizer_defaults.h.
This allows one to change costs without having to compile a lot of
files.
- Updated costs for filter lookup.
- Use a better cost estimate in best_extension_by_limited_search()
for the sorting cost.
- Fixed previous issues with 'filtered' explain column as we are now
using 'records_out' (min rows seen for table) to calculate filtering.
This greatly simplifies the filtering code in
JOIN_TAB::save_explain_data().
This change caused a lot of queries to be optimized differently than
before, which exposed different issues in the optimizer that needs to
be fixed. These fixes are in the following commits. To not have to
change the same test case over and over again, the changes in the test
cases are done in a single commit after all the critical change sets
are done.
InnoDB changes:
- Updated InnoDB to not divide big range cost with 2.
- Added cost for InnoDB (innobase_update_optimizer_costs()).
- Don't mark clustered primary key with HA_KEYREAD_ONLY. This will
prevent that the optimizer is trying to use index-only scans on
the clustered key.
- Disabled ha_innobase::scan_time() and ha_innobase::read_time() and
ha_innobase::rnd_pos_time() as the default engine cost functions now
works good for InnoDB.
Other things:
- Added --show-query-costs (\Q) option to mysql.cc to show the query
cost after each query (good when working with query costs).
- Extended my_getopt with GET_ADJUSTED_VALUE which allows one to adjust
the value that user is given. This is used to change cost from
microseconds (user input) to milliseconds (what the server is
internally using).
- Added include/my_tracker.h ; Useful include file to quickly test
costs of a function.
- Use handler::set_table() in all places instead of 'table= arg'.
- Added SHOW_OPTIMIZER_COSTS to sys variables. These are input and
shown in microseconds for the user but stored as milliseconds.
This is to make the numbers easier to read for the user (less
pre-zeros). Implemented in 'Sys_var_optimizer_cost' class.
- In test_quick_select() do not use index scans if 'no_keyread' is set
for the table. This is what we do in other places of the server.
- Added THD parameter to Unique::get_use_cost() and
check_index_intersect_extension() and similar functions to be able
to provide costs to called functions.
- Changed 'records' to 'rows' in optimizer_trace.
- Write more information to optimizer_trace.
- Added INDEX_BLOCK_FILL_FACTOR_MUL (4) and INDEX_BLOCK_FILL_FACTOR_DIV (3)
to calculate usage space of keys in b-trees. (Before we used numeric
constants).
- Removed code that assumed that b-trees has similar costs as binary
trees. Replaced with engine calls that returns the cost.
- Added Bitmap::find_first_bit()
- Added timings to join_cache for ANALYZE table (patch by Sergei Petrunia).
- Added records_init and records_after_filter to POSITION to remember
more of what best_access_patch() calculates.
- table_after_join_selectivity() changed to recalculate 'records_out'
based on the new fields from best_access_patch()
Bug fixes:
- Some queries did not update last_query_cost (was 0). Fixed by moving
setting thd->...last_query_cost in JOIN::optimize().
- Write '0' as number of rows for const tables with a matching row.
Some internals:
- Engine cost are stored in OPTIMIZER_COSTS structure. When a
handlerton is created, we also created a new cost variable for the
handlerton. We also create a new variable if the user changes a
optimizer cost for a not yet loaded handlerton either with command
line arguments or with SET
@@global.engine.optimizer_cost_variable=xx.
- There are 3 global OPTIMIZER_COSTS variables:
default_optimizer_costs The default costs + changes from the
command line without an engine specifier.
heap_optimizer_costs Heap table costs, used for temporary tables
tmp_table_optimizer_costs The cost for the default on disk internal
temporary table (MyISAM or Aria)
- The engine cost for a table is stored in table_share. To speed up
accesses the handler has a pointer to this. The cost is copied
to the table on first access. If one wants to change the cost one
must first update the global engine cost and then do a FLUSH TABLES.
This was done to be able to access the costs for an open table
without any locks.
- When a handlerton is created, the cost are updated the following way:
See sql/keycaches.cc for details:
- Use 'default_optimizer_costs' as a base
- Call hton->update_optimizer_costs() to override with the engines
default costs.
- Override the costs that the user has specified for the engine.
- One handler open, copy the engine cost from handlerton to TABLE_SHARE.
- Call handler::update_optimizer_costs() to allow the engine to update
cost for this particular table.
- There are two costs stored in THD. These are copied to the handler
when the table is used in a query:
- optimizer_where_cost
- optimizer_scan_setup_cost
- Simply code in best_access_path() by storing all cost result in a
structure. (Idea/Suggestion by Igor)
The MDEV-25004 test innodb_fts.versioning is omitted because ever since
commit 685d958e38 InnoDB would not allow
writes to a database where the redo log file ib_logfile0 is missing.
Fix build failure in comp_err, if git is configured with default,
platform-specific EOL.
The error happens because comp_err is not prepared to handle extraneous
CR characters from errmgs-utf8.txt. Use fopen in text mode to fix.
Table_cache_instance: Define the structure aligned at
the CPU cache line, and remove a pad[] data member.
Krunal Bauskar reported this to improve performance on ARMv8.
aligned_malloc(): Wrapper for the Microsoft _aligned_malloc()
and the ISO/IEC 9899:2011 <stdlib.h> aligned_alloc().
Note: The parameters are in the Microsoft order (size, alignment),
opposite of aligned_alloc(alignment, size).
Note: The standard defines that size must be an integer multiple
of alignment. It is enforced by AddressSanitizer but not by GNU libc
on Linux.
aligned_free(): Wrapper for the Microsoft _aligned_free() and
the standard free().
HAVE_ALIGNED_ALLOC: A new test. Unfortunately, support for
aligned_alloc() may still be missing on some platforms.
We will fall back to posix_memalign() for those cases.
HAVE_MEMALIGN: Remove, along with any use of the nonstandard memalign().
PFS_ALIGNEMENT (sic): Removed; we will use CPU_LEVEL1_DCACHE_LINESIZE.
PFS_ALIGNED: Defined using the C++11 keyword alignas.
buf_pool_t::page_hash_table::create(),
lock_sys_t::hash_table::create():
lock_sys_t::hash_table::resize(): Pad the allocation size to an
integer multiple of the alignment.
Reviewed by: Vladislav Vaintroub
CreateServiceA, OpenServiceA, and couple of other functions do not work
correctly with non-ASCII character, in the special case where application
has defined activeCodePage=UTF8.
Workaround by redefining affected ANSI functions to own wrapper, which
works by converting narrow(ANSI) to wide, then calling wide function.
Deprecate original ANSI service functions, via declspec, so that we can catch
their use.
Workaround Windows' bug in services "ANSI" when process ANSI codepage is
UTF8.
They turn out to work unlike any other API .
Expected behavior : strings be converted from GetACP() to Unicode,
and "wide" function would be then called.
Actual current behavior :
it seems to handle strings as-if they would be encoded in system-default
ACP, rather than process-specific GetACP()
Fix: redefine the OpenService,CreateService and ChangeServiceConfig
and do ANSI-Wide conversion outselves.
Tell compiler to deprecate some ANSI service functions.
xxx
