parallel_servers_target

parallel_servers_target specifies the queue condition for parallel queries on each server. When the number of threads taken by Parallel eXecution (PX) of multiple SQL queries exceeds the specified queue condition, subsequent SQL queries for PX must wait in a queue.

The parallel_servers_target variable takes effect at the tenant level. The value 0 of the parallel_servers_target variable does not have any special meaning. The value of the variable is automatically set when you create a tenant.

When you create a tenant, note that:

1. If you specify the value of the parallel_servers_target variable in the statement, the tenant sets the parallel_servers_target variable based on the specified value.

   You can use the following statement to specify the value of the parallel_servers_target variable when you create a tenant:

   obclient > CREATE TENANT IF NOT EXISTS <tenant_name> CHARSET='utf8mb4', ZONE_LIST=('zone1'), PRIMARY_ZONE='zone1', RESOURCE_POOL_LIST=('<pool_name>') set parallel_servers_target = <specified value>;
   

2. If you do not specify the value of the parallel_servers_target variable, the system automatically specifies a value based on the value of max_cpu when you create a tenant in an OBServer node. To view this value, log on to the tenant and execute the show variables like 'parallel_servers_target' statement.