on disable_indexes(HA_KEY_SWITCH_NONUNIQ_SAVE) the engine does
not know that the long unique is logically unique, because on the
engine level it is not. And the engine disables it,
Change the disable_indexes/enable_indexes API. Instead of the enum
mode, send a key_map of indexes that should be enabled. This way the
server will decide what is unique, not the engine.
Starting with clang-16, MemorySanitizer appears to check that
uninitialized values not be passed by value nor returned.
Previously, it was allowed to copy uninitialized data in such cases.
get_foreign_key_info(): Remove a local variable that was passed
uninitialized to a function.
DsMrr_impl: Initialize key_buffer, because DsMrr_impl::dsmrr_init()
is reading it.
test_bind_result_ext1(): MYSQL_TYPE_LONG is 32 bits, hence we must
use a 32-bit type, such as int. sizeof(long) differs between
LP64 and LLP64 targets.
When computing vcol expression some items use current_thd and that was
not set in MyISAM repair thread. Since all the repair threads belong
to one connection and items should not write into THD we can utilize
table THD for that.
Also fixes: MDEV-30050 Inconsistent results of DISTINCT with NOPAD
Problem:
Key segments for CHAR columns where compared using strnncollsp()
for engines MyISAM and Aria.
This did not work correct in case if the engine applyied trailing
space compression.
Fix:
Replacing ha_compare_text() calls to new functions:
- ha_compare_char_varying()
- ha_compare_char_fixed()
- ha_compare_word()
- ha_compare_word_prefix()
- ha_compare_word_or_prefix()
The code branch corresponding to comparison of CHAR column keys
(HA_KEYTYPE_TEXT segment type) now uses ha_compare_char_fixed()
which calls strnncollsp_nchars().
This patch does not change the behavior for the rest of the code:
- comparison of VARCHAR/TEXT column keys
(HA_KEYTYPE_VARTEXT1, HA_KEYTYPE_VARTEXT2 segments types)
- comparison in the fulltext code
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>
HA_UNIQUE_CHECK was
* only used internally by MyISAM/Aria
* only used for internal temporary tables (for DISTINCT)
* never saved in frm
* saved in MYI/MAD but only for temporary tables
* only set, never checked
it's safe to remove it and free the bit (there are only 16 of them)
The reason for ASAN report was that the MERGE and MYISAM file
had different key definitions, which is not allowed.
Fixed by ensuring that the MERGE code is not copying more key stats
than what is in the MyISAM file.
Other things:
- Give an error if different MyISAM files has different number of
key parts.
The cause of the crash was that test was setting
aria_sort_buffer_size to MAX_LONG_LONG, which caused an overflow in
my_malloc() when trying to allocate the buffer + 8 bytes.
Fixed by reducing max size of sort_buffer for Aria and MyISAM
Other things:
- Added code in maria_repair_parallell() to not allocate a big sort buffer
for small files.
- Updated size of minumim sort buffer in Aria
This patch also fixes some bugs detected by valgrind after this
patch:
- Not enough copy_func elements was allocated by Create_tmp_table() which
causes an memory overwrite in Create_tmp_table::add_fields()
I added an ASSERT() to be able to detect this also without valgrind.
The bug was that TMP_TABLE_PARAM::copy_fields was not correctly set
when calling create_tmp_table().
- Aria::empty_bits is not allocated if there is no varchar/char/blob
fields in the table. Fixed code to take this into account.
This cannot cause any issues as this is just a memory access
into other Aria memory and the content of the memory would not be used.
- Aria::last_key_buff was not allocated big enough. This may have caused
issues with rtrees and ma_extra(HA_EXTRA_REMEMBER_POS) as they
would use the same memory area.
- Aria and MyISAM didn't take extended key parts into account, which
caused problems when copying rec_per_key from engine to sql level.
- Mark asan builds with 'asan' in version strihng to detect these in
not_valgrind_build.inc.
This is needed to not have main.sp-no-valgrind fail with asan.
This patch is the result of running
run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' .
Code style changes have been done on top. The result of this change
leads to the following improvements:
1. Binary size reduction.
* For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by
~400kb.
* A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb.
2. Compiler can better understand the intent of the code, thus it leads
to more optimization possibilities. Additionally it enabled detecting
unused variables that had an empty default constructor but not marked
so explicitly.
Particular change required following this patch in sql/opt_range.cc
result_keys, an unused template class Bitmap now correctly issues
unused variable warnings.
Setting Bitmap template class constructor to default allows the compiler
to identify that there are no side-effects when instantiating the class.
Previously the compiler could not issue the warning as it assumed Bitmap
class (being a template) would not be performing a NO-OP for its default
constructor. This prevented the "unused variable warning".
As of now innodb does not store trx_id for each record in secondary index.
The idea behind is following: let us store only per-page max_trx_id, and
delete-mark the records when they are deleted/updated.
If the read starts, it rememders the lowest id of currently active
transaction. Innodb refers to it as trx->read_view->m_up_limit_id.
See also ReadView::open.
When the page is fetched, its max_trx_id is compared to m_up_limit_id.
If the value is lower, and the secondary index record is not delete-marked,
then this page is just safe to read as is. Else, a clustered index could be
needed ato access. See page_get_max_trx_id call in row_search_mvcc, and the
corresponding switch (row_search_idx_cond_check(...)) below.
Virtual columns are required to be updated in case if the record was
delete-marked. The motivation behind it is documented in
Row_sel_get_clust_rec_for_mysql::operator() near
row_sel_sec_rec_is_for_clust_rec call.
This was basically a description why virtual column computation can
normally happen during SELECT, and, generally, a vcol index access.
Sometimes stats tables are updated by innodb. This starts a new
transaction, and it can happen that it didn't finish to the moment of
SELECT execution, forcing virtual columns recomputation. If the result was
a something that normally outputs a warning, like division by zero, then
it could be outputted in a racy manner.
The solution is to suppress the warnings when a column is computed
for the described purpose.
ignore_wrnings argument is added innobase_get_computed_value.
Currently, it is only true for a call from
row_sel_sec_rec_is_for_clust_rec.
Adding debug output for key and keyseg flags at ha_myisam::open() time.
So now there are three points of debug output:
1. In the very end of mysql_prepare_create_table()
2. In ha_myisam::create(), after the table2myisam() call
3. In ha_myisan::open(), after the mi_open() call
mi_create(), which is is called between 2 and 3, modifies flags for
some data types, so the output in 2 and 3 is different.
In commit 28325b0863
a compile-time option was introduced to disable the macros
DBUG_ENTER and DBUG_RETURN or DBUG_VOID_RETURN.
The parameter name WITH_DBUG_TRACE would hint that it also
covers DBUG_PRINT statements. Let us do that: WITH_DBUG_TRACE=OFF
shall disable DBUG_PRINT() as well.
A few InnoDB recovery tests used to check that some output from
DBUG_PRINT("ib_log", ...) is present. We can live without those checks.
Reviewed by: Vladislav Vaintroub
