SET LEAF

Sets a sync variable to propagate to all leaves in the cluster.

Syntax

SET LEAF variable_name = value

Arguments

  • variable_name: name of the sync variable.

  • value: value to be assigned to the sync variable.

Remarks

  • variable_name must be a sync variable that can sync to all nodes (aggregators and leaves).

  • You cannot this command on a non-sync variable.

  • This command must be run on the master aggregator.

Examples

Example 1

The following example syncs the variable regexp_format to all leaves. SET LEAF can be run on regexp_format because regexp_format is a variable that can sync to all nodes (leaves and aggregators).

This is indicated in the last sentence of the Description column for the variable.

SET LEAF regexp_format = "extended";

Retrieve the variable’s value:

SELECT @@regexp_format;
+-----------------+
| @@regexp_format |
+-----------------+
| extended        |
+-----------------+

Example 2

The following example attempts to sync the variable auto_attach to all leaves. SET LEAF fails because auto_attach is a variable that can sync to all aggregators, only.

This is indicated in the last sentence of the Description column for the variable.

SET LEAF auto_attach = 1;
ERROR 2324 (HY000): This cluster-wide variable exists only on 
aggregators, it's not possible to set a value for leaves

Last modified: June 22, 2022

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