Manually Moving Queries to Different Resource Pools
If you are the database administrator, you can move queries to another resource pool mid-execution using the MOVE_STATEMENT_TO_RESOURCE_POOL meta-function.
You might want to use this feature if a single query is using a large amount of resources, preventing smaller queries from executing.
What Happens When a Query Moves to a Different Resource Pool
When a query is moved from one resource pool to another, it continues executing, provided the target pool has enough resources to accommodate the incoming query. If sufficient resources cannot be assigned in the target pool on at least one node, Vertica cancels the query and attempts to re-plan the query. If Vertica cannot re-plan the query, the query is canceled indefinitely.
When you successfully move a query to a target resource pool, its resources will be accounted for by the target pool and released on the first pool.
If you move a query to a resource pool with PRIORITY HOLD, Vertica cancels the query and queues it on the target pool. This cancellation remains in effect until you change the PRIORITY or move the query to another pool without PRIORITY HOLD. You can use this option if you want to store long-running queries for later use.
You can view the RESOURCE_ACQUISITIONS or RESOURCE_POOL_STATUS system tables to determine if the target pool can accommodate the query you want to move. Be aware that the system tables may change between the time you query the tables and the time you invoke the MOVE_STATEMENT_TO_RESOURCE_POOL meta-function.
When a query successfully moves from one resource pool to another mid-execution, it executes until the greater of the existing and new
RUNTIMECAP is reached. For example, if the
RUNTIMECAP on the initial pool is greater than that on the target pool, the query can execute until the initial
RUNTIMECAP is reached.
Using the MOVE_STATEMENT_TO_RESOURCE_POOL Function
To manually move a query from its current resource pool to another resource pool, use the MOVE_STATEMENT_TO_RESOURCE_POOL meta-function. Provide the session id, transaction id, statement id, and target resource pool name, as shown:
=> SELECT MOVE_STATEMENT_TO_RESOURCE_POOL ('v_vmart_node0001.example.-31427:0x82fbm', 45035996273711993, 1, 'my_target_pool');