Non-Sync Variables

Non-Sync Variable Scopes

Every non-sync variable has one of the following scopes.

• Global. When you set a global variable, its value is effective for your current connection to the node and any other existing or subsequent connections, initiated by any user.

• Session that can also be set globally. When set for the session, the variable’s value is effective for your current connection to the node. When set globally, this variable’s value is NOT effective for your current connection to the node but is effective for any other existing or subsequent connections to the node, initiated by any user.

Most non-sync variables have global scope. Those that instead have the scope session that can also be set globally are indicated in the Description column in the list of non-sync variables.

Note: Use the @@ selector to read the value of a variable. See Reading Variables for more information.

Setting Non-Sync Variables

Non-sync variables with global or session scope can be set globally in the following way.

• SET GLOBAL sets a non-sync variable globally and the variable’s value will not persist if the node is restarted.

  Important

  When you set a session variable using the SET GLOBAL command, you need to additionally run FLUSH CONNECTION POOLS on every aggregator node in the cluster. This will clear the session variable value saved earlier in the connection pools and enable the aggregator and leaf nodes to use the new value.

• To set the variable’s value to take effect when the node starts, run the following command to update the node’s configuration.

  • For SingleStore Toolbox: Run sdb-admin update-config at the Linux command line.

Specify the --all flag if you want to propagate the non-sync variable’s value to all nodes. You can also use the --set-global flag to have the variable’s value take effect immediately (assuming the node is running and the variable can be set at runtime) in addition to when the node restarts.