Withing this task the following changes were made:
- Added sending of metadata info in prepare phase for the admin related
command (check table, checksum table, repair, optimize, analyze).
- Refactored implmentation of HELP command to support its execution in
PS mode
- Added support for execution of LOAD INTO and XA- related statements
in PS mode
- Modified mysqltest.cc to run statements in PS mode unconditionally
in case the option --ps-protocol is set. Formerly, only those statements
were executed using PS protocol that matched the hard-coded regular expression
- Fixed the following issues:
The statement
explain select (select 2)
executed in regular and PS mode produces different results:
MariaDB [test]> prepare stmt from "explain select (select 2)";
Query OK, 0 rows affected (0,000 sec)
Statement prepared
MariaDB [test]> execute stmt;
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
| 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used |
| 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used |
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
2 rows in set (0,000 sec)
MariaDB [test]> explain select (select 2);
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
| 1 | SIMPLE | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used |
+------+-------------+-------+------+---------------+------+---------+------+------+----------------+
1 row in set, 1 warning (0,000 sec)
In case the statement
CREATE TABLE t1 SELECT * FROM (SELECT 1 AS a, (SELECT a+0)) a
is run in PS mode it fails with the error
ERROR 1054 (42S22): Unknown column 'a' in 'field list'.
- Uniform handling of read-only variables both in case the SET var=val
statement is executed as regular or prepared statememt.
- Fixed assertion firing on handling LOAD DATA statement for temporary tables
- Relaxed assert condition in the function lex_end_stage1() by adding
the commands SQLCOM_ALTER_EVENT, SQLCOM_CREATE_PACKAGE,
SQLCOM_CREATE_PACKAGE_BODY to a list of supported command
- Removed raising of the error ER_UNSUPPORTED_PS in the function
check_prepared_statement() for the ALTER VIEW command
- Added initialization of the data memember st_select_lex_unit::last_procedure
(assign NULL value) in the constructor
Without this change the test case main.ctype_utf8 fails with the following
report in case it is run with the optoin --ps-protocol.
mysqltest: At line 2278: query 'VALUES (_latin1 0xDF) UNION VALUES(_utf8'a' COLLATE utf8_bin)' failed: 2013: Lost connection
- The following bug reports were fixed:
MDEV-24460: Multiple rows result set returned from stored
routine over prepared statement binary protocol is
handled incorrectly
CONC-519: mariadb client library doesn't handle server_status and
warnign_count fields received in the packet
COM_STMT_EXECUTE_RESPONSE.
Reasons for these bug reports have the same nature and caused by
missing loop iteration on results sent by server in response to
COM_STMT_EXECUTE packet.
Enclosing of statements for processing of COM_STMT_EXECUTE response
in the construct like
do
{
...
} while (!mysql_stmt_next_result());
fixes the above mentioned bug reports.
This feature adds the functionality of ignorability for indexes.
Indexes are not ignored be default.
To control index ignorability explicitly for a new index,
use IGNORE or NOT IGNORE as part of the index definition for
CREATE TABLE, CREATE INDEX, or ALTER TABLE.
Primary keys (explicit or implicit) cannot be made ignorable.
The table INFORMATION_SCHEMA.STATISTICS get a new column named IGNORED that
would store whether an index needs to be ignored or not.
- multi_range_read_info_const now uses the new records_in_range interface
- Added handler::avg_io_cost()
- Don't calculate avg_io_cost() in get_sweep_read_cost if avg_io_cost is
not 1.0. In this case we trust the avg_io_cost() from the handler.
- Changed test_quick_select to use TIME_FOR_COMPARE instead of
TIME_FOR_COMPARE_IDX to align this with the rest of the code.
- Fixed bug when using test_if_cheaper_ordering where we didn't use
keyread if index was changed
- Fixed a bug where we didn't use index only read when using order-by-index
- Added keyread_time() to HEAP.
The default keyread_time() was optimized for blocks and not suitable for
HEAP. The effect was the HEAP prefered table scans over ranges for btree
indexes.
- Fixed get_sweep_read_cost() for HEAP tables
- Ensure that range and ref have same cost for simple ranges
Added a small cost (MULTI_RANGE_READ_SETUP_COST) to ranges to ensure
we favior ref for range for simple queries.
- Fixed that matching_candidates_in_table() uses same number of records
as the rest of the optimizer
- Added avg_io_cost() to JT_EQ_REF cost. This helps calculate the cost for
HEAP and temporary tables better. A few tests changed because of this.
- heap::read_time() and heap::keyread_time() adjusted to not add +1.
This was to ensure that handler::keyread_time() doesn't give
higher cost for heap tables than for normal tables. One effect of
this is that heap and derived tables stored in heap will prefer
key access as this is now regarded as cheap.
- Changed cost for index read in sql_select.cc to match
multi_range_read_info_const(). All index cost calculation is now
done trough one function.
- 'ref' will now use quick_cost for keys if it exists. This is done
so that for '=' ranges, 'ref' is prefered over 'range'.
- scan_time() now takes avg_io_costs() into account
- get_delayed_table_estimates() uses block_size and avg_io_cost()
- Removed default argument to test_if_order_by_key(); simplifies code
This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range
conditions over indexes. In many cases usage of such filters reduce
the number of disk seeks spent for fetching table rows.
In this implementation the choice of what possible filter to be applied
(if any) is made purely on cost-based considerations.
This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.
Besides this patch contains a better implementation of the generic
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.
This patch supports the feature for InnoDB and MyISAM.
