Distributed Query Processing

Distributed query processing (DQP) improves performance in IQ multiplex configurations by spreading work across multiple nodes in the cluster.

You need not set any configuration options to activate distributed query processing. Unless you disable DQP by setting the DQP_ENABLED logical server policy option to 0, DQP occurs automatically for qualifying queries when:

The server is part of a multiplex where servers have established MIPC (multiplex interprocess communication) connections. Servers establish these connections automatically on startup. To verify, run sp_iqmpxinfo and look for active status in the mipc_public_state column.

If you configured private interconnect on the multiplex and expect DQP to run on private interconnect, run sp_iqmpxinfo and look for active status in the mipc_private_state column.
The logical server of the current connection has at least one other member node available.
Note: To control which multiplex nodes participate in distributed query processing, partition nodes into logical servers.
The shared temporary dbspace has writable files available. See IQ Shared Temporary Dbspace in Administration: Database.
Note: To use DQP without configuring a shared temporary dbspace, set the DQP_ENABLED logical server policy option to 2 to enable DQP over the network.

Use temporary database options to control DQP for the current connection. Setting the temporary database option DQP_ENABLED to OFF disables DQP for all queries executed on the current connection.

If the DQP_ENABLED logical server policy option is set to 1 and the DQP_ENABLED database option is set to ON, setting DQP_ENABLED_OVER_NETWORK to ON forces queries executed on the current connection to use DQP over the network.

If the DQP_ENABLED logical server policy option is set to 2 to force all queries to use DQP over the network, setting the database option DQP_ENABLED to OFF forces queries executed on the current connection to run in simplex mode.

If you enable DQP over the network at the connection level, the only way to disable it at the connection level is to set DQL_ENABLED database option OFF. This forces all queries run on the connection to run in simplex mode. If you enable DQL over the network, no queries use the shared temporary store.