InnoDB
Startup Options and System Variables
1253
Version Introduced
5.0.82
Command-Line Format
--innodb_use_legacy_cardinality_algorithm=#
Option-File Format
innodb_use_legacy_cardinality_algorithm
Option Sets Variable
Yes,
innodb_use_legacy_cardinality_algorithm
[1252]
Variable Name
innodb_use_legacy_cardinality_algorithm
Variable Scope
Global
Dynamic Variable
Yes
Permitted Values
Type
boolean
Default
ON
InnoDB
uses random numbers to generate dives into indexes for calculating index cardinality.
However, under certain conditions, the algorithm does not generate random numbers, so
ANALYZE TABLE
sometimes does not update cardinality estimates properly. An alternative
algorithm was introduced in MySQL 5.0.82 with better randomization properties, and the
innodb_use_legacy_cardinality_algorithm
[1252]
, system variable which algorithm to
use. The default value of the variable is 1 (
ON
), to use the original algorithm for compatibility with
existing applications. The variable can be set to 0 (
OFF
) to use the new algorithm with improved
randomness.
•
sync_binlog
[1472]
Version Introduced
5.0.1
Command-Line Format
--sync-binlog=#
Option-File Format
sync_binlog
Option Sets Variable
Yes,
sync_binlog
[1472]
Variable Name
sync_binlog
Variable Scope
Global
Dynamic Variable
Yes
Permitted Values
Platform
Bit Size
32
Type
numeric
Default
0
Range
0 .. 4294967295
Permitted Values
Platform
Bit Size
64
Type
numeric
Default
0
Range
0 .. 18446744073709547520
If the value of this variable is greater than 0, the MySQL server synchronizes its binary log to disk
(using
fdatasync()
) after every
sync_binlog
[1472]
writes to the binary log. There is one write
to the binary log per statement if autocommit is enabled, and one write per transaction otherwise.
The default value of
sync_binlog
[1472]
is 0, which does no synchronizing to disk. A value of 1
is the safest choice, because in the event of a crash you lose at most one statement or transaction
Содержание 5.0
Страница 1: ...MySQL 5 0 Reference Manual ...
Страница 18: ...xviii ...
Страница 60: ...40 ...
Страница 396: ...376 ...
Страница 578: ...558 ...
Страница 636: ...616 ...
Страница 844: ...824 ...
Страница 1234: ...1214 ...
Страница 1426: ...MySQL Proxy Scripting 1406 The following diagram shows an overview of the classes exposed by MySQL Proxy ...
Страница 1427: ...MySQL Proxy Scripting 1407 ...
Страница 1734: ...1714 ...
Страница 1752: ...1732 ...
Страница 1783: ...Configuring Connector ODBC 1763 ...
Страница 1793: ...Connector ODBC Examples 1773 ...
Страница 1839: ...Connector Net Installation 1819 2 You must choose the type of installation to perform ...
Страница 1842: ...Connector Net Installation 1822 5 Once the installation has been completed click Finish to exit the installer ...
Страница 1864: ...Connector Net Visual Studio Integration 1844 Figure 20 24 Debug Stepping Figure 20 25 Function Stepping 1 of 2 ...
Страница 2850: ...2830 ...
Страница 2854: ...2834 ...
Страница 2928: ...2908 ...
Страница 3000: ...2980 ...
Страница 3122: ...3102 ...
Страница 3126: ...3106 ...
Страница 3174: ...3154 ...
Страница 3232: ...3212 ...