RAND() and UUID() are treated differently with respect to subquery
materialization both should be marked as uncacheable, forcing materialization.
Altered Create_func_uuid(_short)::create_builder().
Added comment in header about UNCACHEABLE_RAND meaning also unmergeable.
In MariaDB up to 10.11, the test_if_cheaper_ordering() code (that tries
to optimizer how GROUP BY is executed) assumes that if a table scan is used
then if there is any index usable by GROUP BY it will be used.
The reason MySQL 10.4 provides a better plan is because of two differences:
- Plans using 'ref' has a cost of 1/10 of what it should be (as a
protection against table scans). This is why 'ref' is used in 10.4
and not in 10.5.
- When 'ref' is used, then GROUP BY will not use an index for GROUP BY.
In MariaDB 10.5 the chosen plan is a table scan (as it calculated to be
faster) but as 'ref' is not used, the test_if_cheaper_ordering()
optimizer phase decides (as ref is not usd) to use an index for GROUP BY,
which has bad performance.
Description of fix:
- All new code is protected by the "optimizer_adjust_secondary_key_costs"
variable, which is now a bit map, and is only executed if the option
"disable_forced_index_in_group_by" set.
- Corrects GROUP BY handling in test_if_cheaper_ordering() by making
the choise of using and index with GROUP BY cost based instead of rule
based.
- Adds TIME_FOR_COMPARE to all costs, when using group by, to make
read_time, index_scan_time and range_cost comparable.
Other things:
- Made optimizer_adjust_secondary_key_costs a bit map (compatible with old
code).
Notes:
Current code ignores costs for the algorithm used when doing GROUP
BY on the first table:
- Create an in-memory temporary table for handling group by and doing a
filesort of the result file
We can probably in 10.6 continue to ignore this cost.
This patch should NOT be merged to 11.0 series (not needed in 11.0).
(Variant#3: Allow cross-charset comparisons, use a special
CHARSET_INFO to create lookup keys. Review input addressed.)
Equalities that compare utf8mb{3,4}_general_ci strings, like:
WHERE ... utf8mb3_key_col=utf8mb4_value (MB3-4-CMP)
can now be used to construct ref[const] access and also participate
in multiple-equalities.
This means that utf8mb3_key_col can be used for key-lookups when
compared with an utf8mb4 constant, field or expression using '=' or
'<=>' comparison operators.
This is controlled by optimizer_switch='cset_narrowing=on', which is
OFF by default.
IMPLEMENTATION
Item value comparison in (MB3-4-CMP) is done using utf8mb4_general_ci.
This is valid as any utf8mb3 value is also an utf8mb4 value.
When making index lookup value for utf8mb3_key_col, we do "Charset
Narrowing": characters that are in the Basic Multilingual Plane (=BMP) are
copied as-is, as they can be represented in utf8mb3. Characters that are
outside the BMP cannot be represented in utf8mb3 and are replaced
with U+FFFD, the "Replacement Character".
In utf8mb4_general_ci, the Replacement Character compares as equal to any
character that's not in BMP. Because of this, the constructed lookup value
will find all index records that would be considered equal by the original
condition (MB3-4-CMP).
Approved-by: Monty <monty@mariadb.org>
remove old deprecation helpers that were not used anywhere.
create new deprecation helpers and enforce their usage
this also removes inconsistencies in reporting deprecation:
sometimes it was ER_WARN_DEPRECATED_SYNTAX (1287),
sometimes ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT (1681),
sometimes a warning, sometimes a note.
it should always be
* ER_WARN_DEPRECATED_SYNTAX
* a warning (because it's something actionable, not purely informational)
In particular:
* @@debug
deprecated since 5.5.37
* sr_YU locale
deprecated since 10.0.11
* "engine_condition_pushdown" in the @@optimizer_switch
deprecated since 10.1.1
* @@date_format, @@datetime_format, @@time_format, @@max_tmp_tables
deprecated since 10.1.2
* @@wsrep_causal_reads
deprecated since 10.1.3
* "parser" in mroonga table comment
deprecated since 10.2.11
(Review input addressed)
(Added handling of UPDATE/DELETE and partitioning w/o index)
If the properties of the used collation allow, do the following
equivalent rewrites:
1. UPPER(key_col)=expr -> key_col=expr
expr=UPPER(key_col) -> expr=key_col
(also rewrite both sides of the equality at the same time)
2. UPPER(key_col) IN (constant-list) -> key_col IN (constant-list)
- Mark utf8mb{3,4}_general_ci as collations that allow this.
- Add optimizer_switch='sargable_casefold=ON' to control this.
(ON by default in this patch)
- Cover the rewrite in Optimizer Trace, rewrite name is
"sargable_casefold_removal".
Introduces @@optimizer_switch flag: hash_join_cardinality
When this option is on, use EITS statistics to produce tighter bounds
for hash join output cardinality.
This patch is an extension / replacement to a similar patch in 10.6
New features:
- optimizer_switch hash_join_cardinality is on by default
- records_out is set to fanout when HASH is used
- Fixed bug in is_eits_usable: The function did not work with views
Introduce @@optimizer_switch flag: hash_join_cardinality
When it is on, use EITS statistics to produce tighter bounds for
hash join output cardinality.
Amended by Monty.
Reviewed by: Monty <monty@mariadb.org>
1. system_versioning_insert_history session variable allows
pseudocolumns ROW_START and ROW_END be specified in INSERT,
INSERT..SELECT and LOAD DATA.
2. Cleaned up select_insert::send_data() from setting vers_write as
this parameter is now set on TABLE initialization.
4. Replication of system_versioning_insert_history via option_bits in
OPTIONS_WRITTEN_TO_BIN_LOG.
Underlying causes of all bugs mentioned below are same. This patch fixes
all of them:
1) MDEV-25028: ASAN use-after-poison in
base_list_iterator::next or Assertion `sl->join == 0' upon
INSERT .. RETURNING via PS
2) MDEV-25187: Assertion `inited == NONE || table->open_by_handler'
failed or Direct leak in init_dynamic_array2 upon INSERT .. RETURNING
and memory leak in init_dynamic_array2
3) MDEV-28740: crash in INSERT RETURNING subquery in prepared statements
4) MDEV-27165: crash in base_list_iterator::next
5) MDEV-29686: Assertion `slave == 0' failed in
st_select_lex_node::attach_single
Analysis:
consider this statement:
INSERT(1)...SELECT(2)...(SELECT(3)...) RETURNING (SELECT(4)...)
When RETURNING is encountered, add_slave() changes how selects are linked.
It makes the builtin_select(1) slave of SELECT(2). This causes
losing of already existing slave(3) (which is nested select of SELECT of
INSERT...SELECT). When really, builtin_select (1) shouldn't be slave to
SELECT(2) because it is not nested within it. Also, push_select() to use
correct context also changed how select are linked.
During reinit_stmt_before_use(), we expect the selects to
be cleaned-up and have join=0. Since these selects are not linked correctly,
clean-up doesn't happen correctly so join is not NULL. Hence the crash.
Fix:
IF we are parsing RETURNING, make is_parsing_returning= true for
current select. get rid of add_slave(). In place of push_select(), used
push_context() to have correct context (the context of builtin_select)
to resolve items in item_list. And add these items to item_list of
builtin_select.
rename OPTION_KEEP_LOG -> OPTION_BINLOG_THIS_TRX.
Meaning: transaction cache will be written to binlog even on rollback.
convert log_current_statement to OPTION_BINLOG_THIS_STMT.
Meaning: the statement will be written to binlog (or trx binlog cache)
even if it normally wouldn't be.
setting OPTION_BINLOG_THIS_STMT must always set OPTION_BINLOG_THIS_TRX,
otherwise the statement won't be logged if the transaction is rolled back.
Use OPTION_BINLOG_THIS to set both.
- DISCARD/IMPORT TABLESPACE are the only tablespace commands left
- TABLESPACE arguments for CREATE TABLE and ALTER ... ADD PARTITION are
ignored.
- Tablespace names are not shown anymore in .frm and not shown in
information schema
Other things
- Removed end spaces from sql/CMakeList.txt
When converting a table (test.s3_table) from S3 to another engine, the
following will be logged to the binary log:
DROP TABLE IF EXISTS test.t1;
CREATE OR REPLACE TABLE test.t1 (...) ENGINE=new_engine
INSERT rows to test.t1 in binary-row-log-format
The bug is that the above statements are logged one by one to the binary
log. This means that a fast slave, configured to use the same S3 storage
as the master, would be able to execute the DROP and CREATE from the
binary log before the master has finished the ALTER TABLE.
In this case the slave would ignore the DROP (as it's on a S3 table) but
it will stop on CREATE of the local tale, as the table is still exists in
S3. The REPLACE part will be ignored by the slave as it can't touch the
S3 table.
The fix is to ensure that all the above statements is written to binary
log AFTER the table has been deleted from S3.
MDEV-21605 Clean up and speed up interfaces for binary row logging
MDEV-21617 Bug fix for previous version of this code
The intention is to have as few 'if' as possible in ha_write() and
related functions. This is done by pre-calculating once per statement the
row_logging state for all tables.
Benefits are simpler and faster code both when binary logging is disabled
and when it's enabled.
Changes:
- Added handler->row_logging to make it easy to check it table should be
row logged. This also made it easier to disabling row logging for system,
internal and temporary tables.
- The tables row_logging capabilities are checked once per "statements
that updates tables" in THD::binlog_prepare_for_row_logging() which
is called when needed from THD::decide_logging_format().
- Removed most usage of tmp_disable_binlog(), reenable_binlog() and
temporary saving and setting of thd->variables.option_bits.
- Moved checks that can't change during a statement from
check_table_binlog_row_based() to check_table_binlog_row_based_internal()
- Removed flag row_already_logged (used by sequence engine)
- Moved binlog_log_row() to a handler::
- Moved write_locked_table_maps() to THD::binlog_write_table_maps() as
most other related binlog functions are in THD.
- Removed binlog_write_table_map() and binlog_log_row_internal() as
they are now obsolete as 'has_transactions()' is pre-calculated in
prepare_for_row_logging().
- Remove 'is_transactional' argument from binlog_write_table_map() as this
can now be read from handler.
- Changed order of 'if's in handler::external_lock() and wsrep_mysqld.h
to first evaluate fast and likely cases before more complex ones.
- Added error checking in ha_write_row() and related functions if
binlog_log_row() failed.
- Don't clear check_table_binlog_row_based_result in
clear_cached_table_binlog_row_based_flag() as it's not needed.
- THD::clear_binlog_table_maps() has been replaced with
THD::reset_binlog_for_next_statement()
- Added 'MYSQL_OPEN_IGNORE_LOGGING_FORMAT' flag to open_and_lock_tables()
to avoid calculating of binary log format for internal opens. This flag
is also used to avoid reading statistics tables for internal tables.
- Added OPTION_BINLOG_LOG_OFF as a simple way to turn of binlog temporary
for create (instead of using THD::sql_log_bin_off.
- Removed flag THD::sql_log_bin_off (not needed anymore)
- Speed up THD::decide_logging_format() by remembering if blackhole engine
is used and avoid a loop over all tables if it's not used
(the common case).
- THD::decide_logging_format() is not called anymore if no tables are used
for the statement. This will speed up pure stored procedure code with
about 5%+ according to some simple tests.
- We now get annotated events on slave if a CREATE ... SELECT statement
is transformed on the slave from statement to row logging.
- In the original code, the master could come into a state where row
logging is enforced for all future events if statement could be used.
This is now partly fixed.
Other changes:
- Ensure that all tables used by a statement has query_id set.
- Had to restore the row_logging flag for not used tables in
THD::binlog_write_table_maps (not normal scenario)
- Removed injector::transaction::use_table(server_id_type sid, table tbl)
as it's not used.
- Cleaned up set_slave_thread_options()
- Some more DBUG_ENTER/DBUG_RETURN, code comments and minor indentation
changes.
- Ensure we only call THD::decide_logging_format_low() once in
mysql_insert() (inefficiency).
- Don't annotate INSERT DELAYED
- Removed zeroing pos_in_table_list in THD::open_temporary_table() as it's
already 0
MDEV-19964 S3 replication support
Added new configure options:
s3_slave_ignore_updates
"If the slave has shares same S3 storage as the master"
s3_replicate_alter_as_create_select
"When converting S3 table to local table, log all rows in binary log"
This allows on to configure slaves to have the S3 storage shared or
independent from the master.
Other thing:
Added new session variable '@@sql_if_exists' to force IF_EXIST to DDL's.
This patch introduces the optimization that allows range optimizer to
consider index range scans that are built employing NOT NULL predicates
inferred from WHERE conditions and ON expressions.
The patch adds a new optimizer switch not_null_range_scan.
The MDEV-17262 commit 26432e49d3
was skipped. In Galera 4, the implementation would seem to require
changes to the streaming replication.
In the tests archive.rnd_pos main.profiling, disable_ps_protocol
for SHOW STATUS and SHOW PROFILE commands until MDEV-18974
has been fixed.
