gcache.size

Overview

Defines the amount of disk space the node should use in caching writesets

The wsrep_provider_options system variable applies to MariaDB Enterprise Cluster, powered by Galera and to Galera Cluster available with MariaDB Community Server. This page relates specifically to the gcache.size wsrep_provider_options.

See also: wsrep Provider Options for MariaDB Enterprise Server 10.6, in 10.5 ES, in 10.4 ES, in 10.3 ES, in 10.2 ES, in 10.6 CS, in 10.5 CS, in 10.4 CS, in 10.3 CS, and in 10.2 CS

USAGE

DETAILS

When nodes receive state transfers, they cannot process incoming write-sets until they finish updating their state. Under certain methods, the node that sends the state transfer is similarly blocked. To prevent the database from falling further behind, GCache saves the incoming write-sets on memory-mapped files to disk.

The gcache.size option defines the amount of disk space to allocate for the present ring buffer storage. The node allocates this space when it starts the database server.

Attribute

Value

Option Name

gcache.size

Default Value

128M

Dynamic

NO

Debug

NO

SYNONYMS

SCHEMA

PARAMETERS

SKYSQL

PRIVILEGES

EXAMPLES

Display Current Value

wsrep_provider_options define optional settings the node passes to the wsrep provider.

To display current wsrep_provider_options values:

SHOW GLOBAL VARIABLES LIKE 'wsrep_provider_options';

The expected output will display the option and the value. Options with no default value, for example SSL options, will not be displayed in the output.

Set in Configuration File

When changing a setting for a wsrep_provider_options in the config file, you must list EVERY option that is to have a value other than the default value. Options that are not explicitly listed are reset to the default value.

Options are set in the my.cnf configuration file. Use the ; delimiter to set multiple options.

The configuration file must be updated on each node. A restart to each node is needed for changes to take effect.

Use a quoted string that includes every option where you want to override the default value. Options that are not in the list will reset to their default value.

To set the option in the configuration file:

wsrep_provider_options='gcache.size=168M;gcache.debug=YES;gcs.fc_limit=NO;socket.send_buf_size=NO;evs.keepalive_period=PT3S'

Set Dynamically

The gcache.size option cannot be set dynamically. It can only be set in the configuration file.

Trying to change a non-dynamic option with SET results in an error:

ERROR 1210 (HY000): Incorrect arguments to SET

ERROR HANDLING

FEATURE INTERACTION

RESPONSES

DIAGNOSIS

ISO 9075:2016

CHANGE HISTORY

Release Series

History

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

10.6 Community

  • Present starting in MariaDB Community Server 10.6.0.

10.5 Enterprise

  • Present starting in MariaDB Enterprise Server 10.5.3-1.

10.5 Community

  • Present starting in MariaDB Community Server 10.5.0.

10.4 Enterprise

  • Present starting in MariaDB Enterprise Server 10.4.6-1.

10.4 Community

  • Present starting in MariaDB Community Server 10.4.0.

10.3 Enterprise

  • Present starting in MariaDB Enterprise Server 10.3.16-1.

10.3 Community

  • Present starting in MariaDB Community Server 10.3.0.

10.2 Enterprise

  • Present starting in MariaDB Enterprise Server 10.2.25-1.

10.2 Community

  • Present starting in MariaDB Community Server 10.2.0.

EXTERNAL REFERENCES