Startup Options Used with Binary Logging
System Variables Used with Binary Logging
You can use the mysqld options and system variables that are described in this section to affect the operation of the binary log as well as to control which statements are written to the binary log. For additional information about the binary log, see Section 5.2.4, “The Binary Log”. For additional information about using MySQL server options and system variables, see Section 5.1.3, “Server Command Options”, and Section 5.1.4, “Server System Variables”.
The following list describes startup options for enabling and configuring the binary log. System variables used with binary logging are discussed later in this section.
Command-Line Format | --binlog-row-event-max-size=# | ||
Option-File Format | binlog-row-event-max-size | ||
Permitted Values (<= 5.6.5) | |||
Platform Bit Size | 32 | ||
Type | numeric | ||
Default | 1024 | ||
Range | 256 .. 4294967295 | ||
Permitted Values (<= 5.6.5) | |||
Platform Bit Size | 64 | ||
Type | numeric | ||
Default | 1024 | ||
Range | 256 .. 18446744073709547520 | ||
Permitted Values (>= 5.6.6) | |||
Platform Bit Size | 32 | ||
Type | numeric | ||
Default | 8192 | ||
Range | 256 .. 4294967295 | ||
Permitted Values (>= 5.6.6) | |||
Platform Bit Size | 64 | ||
Type | numeric | ||
Default | 8192 | ||
Range | 256 .. 18446744073709547520 |
Specify the maximum size of a row-based binary log event, in bytes. Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256. The default is 8192 as of MySQL 5.6.6 and 1024 before that. See Section 17.1.2, “Replication Formats”.
Command-Line Format | --log-bin | ||
Option-File Format | log-bin | ||
System Variable Name | log_bin | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values | |||
Type | file name |
Enable binary logging. The server logs all statements that change data to the binary log, which is used for backup and replication. See Section 5.2.4, “The Binary Log”.
The option value, if given, is the basename for the log
sequence. The server creates binary log files in sequence by
adding a numeric suffix to the basename. It is recommended
that you specify a basename (see Section B.5.8, “Known Issues in MySQL”, for
the reason). Otherwise, MySQL uses
as the basename.
host_name
-bin
In MySQL 5.6.5 and later, when the server reads an entry
from the index file, it checks whether the entry contains a
relative path, and if it does, the relative part of the path
in replaced with the absolute path set using the
--log-bin
option. An absolute path remains
unchanged; in such a case, the index must be edited manually
to enable the new path or paths to be used. Previous to
MySQL 5.6.5, manual intervention was required whenever
relocating the binary log or relay log files. (Bug
#11745230, Bug #12133)
Setting this option causes the
log_bin
system variable to
be set to ON
(or 1
),
and not to the basename. Beginning with MySQL 5.6.2, the
binary log filename (with path) is available as the
log_bin_basename
system
variable.
Command-Line Format | --log-bin-index=name | ||
Option-File Format | log-bin-index | ||
Permitted Values | |||
Type | file name |
The index file for binary log file names. See
Section 5.2.4, “The Binary Log”. If you omit the file name, and
if you did not specify one with
--log-bin
, MySQL uses
as the file name.
host_name
-bin.index
--log-bin-trust-function-creators[={0|1}]
Command-Line Format | --log-bin-trust-function-creators | ||
Option-File Format | log-bin-trust-function-creators | ||
System Variable Name | log_bin_trust_function_creators | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
This option sets the corresponding
log_bin_trust_function_creators
system variable. If no argument is given, the option sets
the variable to 1.
log_bin_trust_function_creators
affects how MySQL enforces restrictions on stored function
and trigger creation. See
Section 20.7, “Binary Logging of Stored Programs”.
--log-bin-use-v1-row-events[={0|1}]
Introduced | 5.6.6 | ||
Command-Line Format | --log-bin-use-v1-row-events[={0|1}] | ||
Option-File Format | log-bin-use-v1-row-events | ||
System Variable Name | log_bin_use_v1_row_events | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values (>= 5.6.6) | |||
Type | boolean | ||
Default | 0 |
Version 2 binary log row events are available beginning with
MySQL 5.6.6; however, Version 2 events cannot be read by
previous MySQL Server releases. Setting this option to 1
causes mysqld to write the binary log
using Version 1 logging events, which is the only version of
binary log events used in previous releases, and thus
produce binary logs that can be read by older slaves.
Setting --log-bin-use-v1-row-events
to 0
(the default) causes mysqld to use
Version 2 binary log events.
The value used for this option can be obtained from the
read-only
log_bin_use_v1_row_events
system variable.
--log-bin-use-v1-row-events
is chiefly of
interest when setting up replication conflict detection and
resolution using NDB$EPOCH_TRANS()
as the
conflict detection function, which requires Version 2 binary
log row events. Thus, this option and
--ndb-log-transaction-id
are
not compatible.
For more information, see Section 18.6.11, “MySQL Cluster Replication Conflict Resolution”.
Command-Line Format | --log-short-format | ||
Option-File Format | log-short-format | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
Log less information to the binary log and slow query log, if they have been activated.
Statement selection options. The options in the following list affect which statements are written to the binary log, and thus sent by a replication master server to its slaves. There are also options for slave servers that control which statements received from the master should be executed or ignored. For details, see Section 17.1.4.3, “Replication Slave Options and Variables”.
Command-Line Format | --binlog-do-db=name | ||
Option-File Format | binlog-do-db | ||
Permitted Values | |||
Type | string |
This option affects binary logging in a manner similar to
the way that
--replicate-do-db
affects
replication.
The effects of this option depend on whether the
statement-based or row-based logging format is in use, in
the same way that the effects of
--replicate-do-db
depend on
whether statement-based or row-based replication is in use.
You should keep in mind that the format used to log a given
statement may not necessarily be the same as that indicated
by the value of
binlog_format
. For example,
DDL statements such as CREATE
TABLE
and ALTER
TABLE
are always logged as statements, without
regard to the logging format in effect, so the following
statement-based rules for --binlog-do-db
always apply in determining whether or not the statement is
logged.
Statement-based logging.
Only those statements are written to the binary log where
the default database (that is, the one selected by
USE
) is
db_name
. To specify more than
one database, use this option multiple times, once for
each database; however, doing so does
not cause cross-database statements
such as UPDATE
to be logged while a different
database (or no database) is selected.
some_db.some_table
SET
foo='bar'
To specify multiple databases you must use multiple instances of this option. Because database names can contain commas, the list will be treated as the name of a single database if you supply a comma-separated list.
An example of what does not work as you might expect when
using statement-based logging: If the server is started with
--binlog-do-db=sales
and you
issue the following statements, the
UPDATE
statement is
not logged:
USE prices; UPDATE sales.january SET amount=amount+1000;
The main reason for this “just check the default
database” behavior is that it is difficult from the
statement alone to know whether it should be replicated (for
example, if you are using multiple-table
DELETE
statements or
multiple-table UPDATE
statements that act across multiple databases). It is also
faster to check only the default database rather than all
databases if there is no need.
Another case which may not be self-evident occurs when a
given database is replicated even though it was not
specified when setting the option. If the server is started
with --binlog-do-db=sales
, the following
UPDATE
statement is logged
even though prices
was not included when
setting --binlog-do-db
:
USE sales; UPDATE prices.discounts SET percentage = percentage + 10;
Because sales
is the default database
when the UPDATE
statement is
issued, the UPDATE
is logged.
Row-based logging.
Logging is restricted to database
db_name
. Only changes to tables
belonging to db_name
are
logged; the default database has no effect on this.
Suppose that the server is started with
--binlog-do-db=sales
and
row-based logging is in effect, and then the following
statements are executed:
USE prices; UPDATE sales.february SET amount=amount+100;
The changes to the february
table in the
sales
database are logged in accordance
with the UPDATE
statement;
this occurs whether or not the
USE
statement was issued.
However, when using the row-based logging format and
--binlog-do-db=sales
, changes
made by the following UPDATE
are not logged:
USE prices; UPDATE prices.march SET amount=amount-25;
Even if the USE prices
statement were
changed to USE sales
, the
UPDATE
statement's
effects would still not be written to the binary log.
Another important difference in
--binlog-do-db
handling for
statement-based logging as opposed to the row-based logging
occurs with regard to statements that refer to multiple
databases. Suppose that the server is started with
--binlog-do-db=db1
, and the
following statements are executed:
USE db1; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20;
If you are using statement-based logging, the updates to
both tables are written to the binary log. However, when
using the row-based format, only the changes to
table1
are logged;
table2
is in a different database, so it
is not changed by the UPDATE
.
Now suppose that, instead of the USE db1
statement, a USE db4
statement had been
used:
USE db4; UPDATE db1.table1 SET col1 = 10, db2.table2 SET col2 = 20;
In this case, the UPDATE
statement is not written to the binary log when using
statement-based logging. However, when using row-based
logging, the change to table1
is logged,
but not that to table2
—in other
words, only changes to tables in the database named by
--binlog-do-db
are logged,
and the choice of default database has no effect on this
behavior.
Command-Line Format | --binlog-ignore-db=name | ||
Option-File Format | binlog-ignore-db | ||
Permitted Values | |||
Type | string |
This option affects binary logging in a manner similar to
the way that
--replicate-ignore-db
affects
replication.
The effects of this option depend on whether the
statement-based or row-based logging format is in use, in
the same way that the effects of
--replicate-ignore-db
depend
on whether statement-based or row-based replication is in
use. You should keep in mind that the format used to log a
given statement may not necessarily be the same as that
indicated by the value of
binlog_format
. For example,
DDL statements such as CREATE
TABLE
and ALTER
TABLE
are always logged as statements, without
regard to the logging format in effect, so the following
statement-based rules for
--binlog-ignore-db
always apply in
determining whether or not the statement is logged.
Statement-based logging.
Tells the server to not log any statement where the
default database (that is, the one selected by
USE
) is
db_name
.
Prior to MySQL 5.6.12, this option caused any statements
containing fully qualified table names not to be logged if
there was no default database specified (that is, when
SELECT
DATABASE()
returned
NULL
). In MySQL 5.6.12 and later, when
there is no default database, no
--binlog-ignore-db
options are applied, and
such statements are always logged. (Bug #11829838, Bug
#60188)
Row-based format.
Tells the server not to log updates to any tables in the
database db_name
. The current
database has no effect.
When using statement-based logging, the following example
does not work as you might expect. Suppose that the server
is started with
--binlog-ignore-db=sales
and
you issue the following statements:
USE prices; UPDATE sales.january SET amount=amount+1000;
The UPDATE
statement
is logged in such a case because
--binlog-ignore-db
applies
only to the default database (determined by the
USE
statement). Because the
sales
database was specified explicitly
in the statement, the statement has not been filtered.
However, when using row-based logging, the
UPDATE
statement's
effects are not written to the binary
log, which means that no changes to the
sales.january
table are logged; in this
instance,
--binlog-ignore-db=sales
causes all changes made to tables in
the master's copy of the sales
database to be ignored for purposes of binary logging.
To specify more than one database to ignore, use this option multiple times, once for each database. Because database names can contain commas, the list will be treated as the name of a single database if you supply a comma-separated list.
You should not use this option if you are using cross-database updates and you do not want these updates to be logged.
Checksum options. Beginning with MySQL 5.6.2, MySQL supports reading and writing of binary log checksums. These are enabled using the two options listed here:
--binlog-checksum={NONE|CRC32}
Introduced | 5.6.2 | ||
Command-Line Format | --binlog-checksum=type | ||
Option-File Format | binlog-checksum | ||
Permitted Values (<= 5.6.5) | |||
Type | string | ||
Default | NONE | ||
Valid Values | NONE | ||
CRC32 | |||
Permitted Values (>= 5.6.6) | |||
Type | string | ||
Default | CRC32 | ||
Valid Values | NONE | ||
CRC32 |
Enabling this option causes the master to write checksums
for events written to the binary log. Set to
NONE
to disable, or the name of the
algorithm to be used for generating checksums; currently,
only CRC32 checksums are supported. As of MySQL 5.6.6, CRC32
is the default.
This option was added in MySQL 5.6.2.
--master-verify-checksum={0|1}
Introduced | 5.6.2 | ||
Command-Line Format | --master-verify-checksum=name | ||
Option-File Format | master-verify-checksum | ||
Permitted Values | |||
Type | boolean | ||
Default | OFF |
Enabling this option causes the master to verify events from the binary log using checksums, and to stop with an error in the event of a mismatch. Disabled by default.
This option was added in MySQL 5.6.2.
To control reading of checksums by the slave (from the relay)
log, use the
--slave-sql-verify-checksum
option.
Testing and debugging options. The following binary log options are used in replication testing and debugging. They are not intended for use in normal operations.
Command-Line Format | --max-binlog-dump-events=# | ||
Option-File Format | max-binlog-dump-events | ||
Permitted Values | |||
Type | numeric | ||
Default | 0 |
This option is used internally by the MySQL test suite for replication testing and debugging.
Command-Line Format | --sporadic-binlog-dump-fail | ||
Option-File Format | sporadic-binlog-dump-fail | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
This option is used internally by the MySQL test suite for replication testing and debugging.
--binlog-rows-query-log-events
Introduced | 5.6.2 | ||
Command-Line Format | --binlog-rows-query-log-events | ||
Option-File Format | binlog-rows-query-log-events | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
Added in MySQL 5.6.2, this option enables
binlog_rows_query_log_events
.
Must be set to OFF
(the default) when
generating logs for a MySQL 5.6.1 or earlier slave server or
version of mysqlbinlog.
The following list describes system variables for controlling
binary logging. They can be set at server startup and some of
them can be changed at runtime using
SET
.
Server options used to control binary logging are listed earlier
in this section. For information about the
sql_log_bin
and
sql_log_off
variables, see
Section 5.1.4, “Server System Variables”.
Command-Line Format | --binlog_cache_size=# | ||
Option-File Format | binlog_cache_size | ||
System Variable Name | binlog_cache_size | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Platform Bit Size | 32 | ||
Type | numeric | ||
Default | 32768 | ||
Range | 4096 .. 4294967295 | ||
Permitted Values | |||
Platform Bit Size | 64 | ||
Type | numeric | ||
Default | 32768 | ||
Range | 4096 .. 18446744073709547520 |
The size of the cache to hold changes to the binary log
during a transaction. A binary log cache is allocated for
each client if the server supports any transactional storage
engines and if the server has the binary log enabled
(--log-bin
option). If you
often use large transactions, you can increase this cache
size to get better performance. The
Binlog_cache_use
and
Binlog_cache_disk_use
status variables can be useful for tuning the size of this
variable. See Section 5.2.4, “The Binary Log”.
binlog_cache_size
sets the size for the
transaction cache only; the size of the statement cache is
governed by the
binlog_stmt_cache_size
system variable.
Introduced | 5.6.2 | ||
System Variable Name | binlog_checksum | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values (<= 5.6.5) | |||
Type | string | ||
Default | NONE | ||
Valid Values | NONE | ||
CRC32 | |||
Permitted Values (>= 5.6.6) | |||
Type | string | ||
Default | CRC32 | ||
Valid Values | NONE | ||
CRC32 |
When enabled, this variable causes the master to write a
checksum for each event in the binary log.
binlog_checksum
supports the values
NONE
(disabled) and
CRC32
. The default is
CRC32
as of MySQL 5.6.6,
NONE
before that.
When binlog_checksum
is disabled (value
NONE
), the server verifies that it is
writing only complete events to the binary log by writing
and checking the event length (rather than a checksum) for
each event.
Changing the value of this variable causes the binary log to be rotated; checksums are always written to an entire binary log file, and never to only part of one.
This variable was added in MySQL 5.6.2.
In MySQL 5.6.6 and later, setting this variable on the
master to a value unrecognized by the slave causes the slave
to set its own binlog_checksum
value to
NONE
, and to stop replication with an
error. (Bug #13553750, Bug #61096) If backward compatibility
with older slaves is a concern, you may want to set the
value explicitly to NONE
.
binlog_direct_non_transactional_updates
Command-Line Format | --binlog_direct_non_transactional_updates[=value] | ||
Option-File Format | binlog_direct_non_transactional_updates | ||
System Variable Name | binlog_direct_non_transactional_updates | ||
Variable Scope | Global, Session | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | boolean | ||
Default | OFF |
Due to concurrency issues, a slave can become inconsistent when a transaction contains updates to both transactional and nontransactional tables. MySQL tries to preserve causality among these statements by writing nontransactional statements to the transaction cache, which is flushed upon commit. However, problems arise when modifications done to nontransactional tables on behalf of a transaction become immediately visible to other connections because these changes may not be written immediately into the binary log.
The
binlog_direct_non_transactional_updates
variable offers one possible workaround to this issue. By
default, this variable is disabled. Enabling
binlog_direct_non_transactional_updates
causes updates to nontransactional tables to be written
directly to the binary log, rather than to the transaction
cache.
binlog_direct_non_transactional_updates
works only for statements that are replicated using the
statement-based binary logging format; that is,
it works only when the value of
binlog_format
is
STATEMENT
, or when
binlog_format
is
MIXED
and a given statement is being
replicated using the statement-based format. This variable
has no effect when the binary log format is
ROW
, or when
binlog_format
is set to
MIXED
and a given statement is replicated
using the row-based format.
Before enabling this variable, you must make certain that
there are no dependencies between transactional and
nontransactional tables; an example of such a dependency
would be the statement INSERT INTO myisam_table
SELECT * FROM innodb_table
. Otherwise, such
statements are likely to cause the slave to diverge from
the master.
In MySQL 5.6, this variable has no effect when
the binary log format is ROW
or
MIXED
. (Bug #51291)
Command-Line Format | --binlog-format=format | ||
Option-File Format | binlog-format | ||
System Variable Name | binlog_format | ||
Variable Scope | Global, Session | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | enumeration | ||
Default | STATEMENT | ||
Valid Values | ROW | ||
STATEMENT | |||
MIXED |
This variable sets the binary logging format, and can be any
one of STATEMENT
, ROW
,
or MIXED
. See
Section 17.1.2, “Replication Formats”.
binlog_format
is set by the
--binlog-format
option at
startup, or by the
binlog_format
variable at
runtime.
While you can change the logging format at runtime, it is
not recommended that you change it
while replication is ongoing. This is due in part to the
fact that slaves do not honor the master's
binlog_format
setting; a
given MySQL Server can change only its own logging format.
In MySQL 5.6, the default format is
STATEMENT
.
Exception: For MySQL Cluster NDB 7.3,
the default is MIXED
; statement-based
replication is not supported for MySQL Cluster.
You must have the SUPER
privilege to set either the global or session
binlog_format
value.
The rules governing when changes to this variable take
effect and how long the effect lasts are the same as for
other MySQL server system variables. See
Section 13.7.4, “SET
Syntax”, for more information.
When MIXED
is specified, statement-based
replication is used, except for cases where only row-based
replication is guaranteed to lead to proper results. For
example, this happens when statements contain user-defined
functions (UDF) or the UUID()
function. An exception to this rule is that
MIXED
always uses statement-based
replication for stored functions and triggers.
There are exceptions when you cannot switch the replication format at runtime:
From within a stored function or a trigger.
If the session is currently in row-based replication mode and has open temporary tables.
From within a transaction.
Trying to switch the format in those cases results in an error.
The binary log format affects the behavior of the following server options:
These effects are discussed in detail in the descriptions of the individual options.
Introduced | 5.6.6 | ||
System Variable Name | binlog_max_flush_queue_time | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | numeric | ||
Default | 0 | ||
Range | 0 .. 100000 |
How long in microseconds to keep reading transactions from
the flush queue before proceeding with the group commit (and
syncing the log to disk, if
sync_binlog
is greater than
0). If the value is 0 (the default), there is no timeout and
the server keeps reading new transactions until the queue is
empty.
Normally,
binlog_max_flush_queue_time
can remain set to 0. If the server processes a large number
of connections (for example, 100 or more) and many short
transactions with low-latency requirements, it may be useful
to set the value larger than 0 to force more frequent
flushes to disk.
This variable was added in MySQL 5.6.6.
Introduced | 5.6.6 | ||
System Variable Name | binlog_order_commits | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | boolean | ||
Default | ON |
If this variable is enabled (the default), transactions are committed in the same order they are written to the binary log. If disabled, transactions may be committed in parallel. In some cases, disabling this variable might produce a performance increment.
This variable was added in MySQL 5.6.6.
Introduced | 5.6.2 | ||
Command-Line Format | --binlog-row-image=image_type | ||
Option-File Format | binlog_row_image | ||
System Variable Name | binlog_row_image=image_type | ||
Variable Scope | Global, Session | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | enumeration | ||
Default | full | ||
Valid Values | full (Log all columns) | ||
minimal (Log only changed columns, and columns needed to identify rows) | |||
noblob (Log all columns, except for unneeded BLOB and TEXT columns) |
In MySQL row-based replication, each row change event contains two images, a “before” image whose columns are matched against when searching for the row to be updated, and an “after” image containing the changes. Normally, MySQL logs full rows (that is, all columns) for both the before and after images. However, it is not strictly necessary to include every column in both images, and we can often save disk, memory, and network usage by logging only those columns which are actually required.
When deleting a row, only the before image is logged, since there are no changed values to propagate following the deletion. When inserting a row, only the after image is logged, since there is no existing row to be matched. Only when updating a row are both the before and after images required, and both written to the binary log.
For the before image, it is necessary only that the minimum
set of columns required to uniquely identify rows is logged.
If the table containing the row has a primary key, then only
the primary key column or columns are written to the binary
log. Otherwise, if the table has a unique key all of whose
columns are NOT NULL
, then only the
columns in the unique key need be logged. (If the table has
neither a primary key nor a unique key without any
NULL
columns, then all columns must be
used in the before image, and logged.) In the after image,
it is necessary to log only the columns which have actually
changed.
In MySQL 5.6, you can cause the server to log full or
minimal rows using the binlog_row_image
system variable. This variable actually takes one of three
possible values, as shown in the following list:
full
: Log all columns in both the
before image and the after image.
minimal
: Log only those columns in
the before image that are required to identify the row
to be changed; log only those columns in the after image
that are actually changed.
noblob
: Log all columns (same as
full
), except for
BLOB
and
TEXT
columns that are not
required to identify rows, or that have not changed.
This variable is not supported by MySQL Cluster; setting
it has no effect on the logging of
NDB
tables. (Bug #16316828)
The default value is full
. In MySQL 5.5
and earlier, full row images are always used for both before
images and after images. If you need to replicate from a
MySQL 5.6 (or later) master to a slave running a previous
version of MySQL, the master should always use this value.
When using minimal
or
noblob
, deletes and updates are
guaranteed to work correctly for a given table if and only
if the following conditions are true for both the source and
destination tables:
All columns must be present and in the same order; each column must use the same data type as its counterpart in the other table.
The tables must have identical primary key definitions.
(In other words, the tables must be identical with the possible exception of indexes that are not part of the tables' primary keys.)
If these conditions are not met, it is possible that the primary key column values in the destination table may prove insufficient to provide a unique match for a delete or update. In this event, no warning or error is issued; the master and slave silently diverge, thus breaking consistency.
Setting this variable has no effect when the binary logging
format is STATEMENT
. When
binlog_format
is
MIXED
, the setting for
binlog_row_image
is applied to changes
that are logged using row-based format, but this setting no
effect on changes logged as statements.
Setting binlog_row_image
on either the
global or session level does not cause an implicit commit;
this means that this variable can be changed while a
transaction is in progress without affecting the
transaction.
Introduced | 5.6.2 | ||
System Variable Name | binlog_rows_query_log_events | ||
Variable Scope | Global, Session | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
The
binlog_rows_query_log_events
system variable affects row-based logging only. When
enabled, it causes a MySQL 5.6.2 or later server to write
informational log events such as row query log events into
its binary log. This information can be used for debugging
and related purposes; such as obtaining the original query
issued on the master when it cannot be reconstructed from
the row updates.
These events are normally ignored by MySQL 5.6.2 and later
programs reading the binary log and so cause no issues when
replicating or restoring from backup. This is not true for a
mysqld or mysqlbinlog
from MySQL 5.6.1 or earlier: When the older version of the
program reading the log encounters an informational log
event, it fails, and stops reading at that point. To make
the binary log readable by slave replication MySQL servers
and other readers (for example,
mysqlbinlog) from a MySQL 5.6.1 or
earlier distribution,
binlog_rows_query_log_events
must be disabled during logging.
Introduced | 5.6.1 | ||
Command-Line Format | --binlog_stmt_cache_size=# | ||
Option-File Format | binlog_stmt_cache_size | ||
System Variable Name | binlog_stmt_cache_size | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Platform Bit Size | 32 | ||
Type | numeric | ||
Default | 32768 | ||
Range | 4096 .. 4294967295 | ||
Permitted Values | |||
Platform Bit Size | 64 | ||
Type | numeric | ||
Default | 32768 | ||
Range | 4096 .. 18446744073709547520 |
This variable determines the size of the cache for the
binary log to hold nontransactional statements issued during
a transaction. Separate binary log transaction and statement
caches are allocated for each client if the server supports
any transactional storage engines and if the server has the
binary log enabled (--log-bin
option). If you often use large nontransactional statements
during transactions, you can increase this cache size to get
better performance. The
Binlog_stmt_cache_use
and
Binlog_stmt_cache_disk_use
status variables can be useful for tuning the size of this
variable. See Section 5.2.4, “The Binary Log”.
The binlog_cache_size
system variable sets the size for the transaction cache.
System Variable Name | log_bin | ||
Variable Scope | Global | ||
Dynamic Variable | No |
Whether the binary log is enabled. If the
--log-bin
option is used,
then the value of this variable is ON
;
otherwise it is OFF
. This variable
reports only on the status of binary logging (enabled or
disabled); it does not actually report the value to which
--log-bin
is set.
Introduced | 5.6.2 | ||
System Variable Name | log_bin_basename | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values | |||
Type | file name | ||
Default | datadir + '/' + hostname + '-bin' |
Holds the name and complete path to the binary log file.
Unlike the log_bin
system
variable, log_bin_basename
reflects the name set with the
--log-bin
server option.
The log_bin_basename
system
variable was added in MySQL 5.6.2.
Introduced | 5.6.4 | ||
System Variable Name | log_bin_index | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values | |||
Type | file name |
The index file for binary log file names.
The log_bin_index
system
variable was added in MySQL 5.6.4.
Introduced | 5.6.6 | ||
Command-Line Format | --log-bin-use-v1-row-events[={0|1}] | ||
Option-File Format | log_bin_use_v1_row_events | ||
System Variable Name | log_bin_use_v1_row_events | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values (>= 5.6.6) | |||
Type | boolean | ||
Default | 0 |
Shows whether Version 2 binary logging, available beginning with MySQL 5.6.6, is in use. A value of 1 shows that the server is writing the binary log using Version 1 logging events (the only version of binary log events used in MySQL 5.6.5 and previous MySQL Server releases), and thus producing a binary log that can be read by older slaves. 0 indicates that Version 2 binary log events are in use.
This variable is read-only. To switch between Version 1 and
Version 2 binary event binary logging, it is necessary to
restart mysqld with the
--log-bin-use-v1-row-events
option.
Other than when performing upgrades of MySQL Cluster
Replication, --log-bin-use-v1-events
is
chiefly of interest when setting up replication conflict
detection and resolution using
NDB$EPOCH_TRANS()
, which requires Version
2 binary row event logging. Thus, this option and
--ndb-log-transaction-id
are
not compatible.
MySQL Cluster NDB 7.3 uses Version 2 binary log row events by default. You should keep this mind when planning upgrades or downgrades, and for setups using MySQL Cluster Replication.
For more information, see Section 18.6.11, “MySQL Cluster Replication Conflict Resolution”.
Command-Line Format | --log-slave-updates | ||
Option-File Format | log_slave_updates | ||
System Variable Name | log_slave_updates | ||
Variable Scope | Global | ||
Dynamic Variable | No | ||
Permitted Values | |||
Type | boolean | ||
Default | FALSE |
Whether updates received by a slave server from a master server should be logged to the slave's own binary log. Binary logging must be enabled on the slave for this variable to have any effect. See Section 17.1.4, “Replication and Binary Logging Options and Variables”.
Introduced | 5.6.2 | ||
System Variable Name | master_verify_checksum | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | boolean | ||
Default | OFF |
Enabling this variable causes the master to examine
checksums when reading from the binary log.
master_verify_checksum
is disabled by
default; in this case, the master uses the event length from
the binary log to verify events, so that only complete
events are read from the binary log.
This variable was added in MySQL 5.6.2.
Command-Line Format | --max_binlog_cache_size=# | ||
Option-File Format | max_binlog_cache_size | ||
System Variable Name | max_binlog_cache_size | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | numeric | ||
Default | 18446744073709547520 | ||
Range | 4096 .. 18446744073709547520 |
If a transaction requires more than this many bytes of memory, the server generates a Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage error. The minimum value is 4096. The maximum possible value is 16EB (exabytes). The maximum recommended value is 4GB; this is due to the fact that MySQL currently cannot work with binary log positions greater than 4GB.
Prior to MySQL 5.6.7, 64-bit Windows platforms truncated the stored value for this variable to 4G, even when it was set to a greater value (Bug #13961678).
max_binlog_cache_size
sets the size for
the transaction cache only; the upper limit for the
statement cache is governed by the
max_binlog_stmt_cache_size
system variable.
In MySQL 5.6, the visibility to sessions of
max_binlog_cache_size
matches that of the
binlog_cache_size
system
variable; in other words, changing its value effects only
new sessions that are started after the value is changed.
Command-Line Format | --max_binlog_size=# | ||
Option-File Format | max_binlog_size | ||
System Variable Name | max_binlog_size | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | numeric | ||
Default | 1073741824 | ||
Range | 4096 .. 1073741824 |
If a write to the binary log causes the current log file size to exceed the value of this variable, the server rotates the binary logs (closes the current file and opens the next one). The minimum value is 4096 bytes. The maximum and default value is 1GB.
A transaction is written in one chunk to the binary log, so
it is never split between several binary logs. Therefore, if
you have big transactions, you might see binary log files
larger than
max_binlog_size
.
If max_relay_log_size
is 0,
the value of
max_binlog_size
applies to
relay logs as well.
Introduced | 5.6.1 | ||
Command-Line Format | --max_binlog_stmt_cache_size=# | ||
Option-File Format | max_binlog_stmt_cache_size | ||
System Variable Name | max_binlog_stmt_cache_size | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Type | numeric | ||
Default | 18446744073709547520 | ||
Range | 4096 .. 18446744073709547520 |
If nontransactional statements within a transaction require more than this many bytes of memory, the server generates an error. The minimum value is 4096. The maximum and default values are 4GB on 32-bit platforms and 16EB (exabytes) on 64-bit platforms.
Prior to MySQL 5.6.7, 64-bit Windows platforms truncated the stored value for this variable to 4G, even when it was set to a greater value (Bug #13961678).
max_binlog_stmt_cache_size
sets the size
for the statement cache only; the upper limit for the
transaction cache is governed exclusively by the
max_binlog_cache_size
system variable.
Command-Line Format | --sync-binlog=# | ||
Option-File Format | sync_binlog | ||
System Variable Name | sync_binlog | ||
Variable Scope | Global | ||
Dynamic Variable | Yes | ||
Permitted Values | |||
Platform Bit Size | 64 | ||
Type | numeric | ||
Default | 0 | ||
Range | 0 .. 4294967295 |
If the value of this variable is greater than 0, the MySQL
server synchronizes its binary log to disk (using
fdatasync()
) after
sync_binlog
commit groups
are written to the binary log. The default value of
sync_binlog
is 0, which
does no synchronizing to disk—in this case, the server
relies on the operating system to flush the binary
log's contents from time to time as for any other file.
A value of 1 is the safest choice because in the event of a
crash you lose at most one commit group from the binary log.
However, it is also the slowest choice (unless the disk has
a battery-backed cache, which makes synchronization very
fast).
User Comments