IQ Shared Temporary Dbspace

A single dbspace for the IQ shared temporary store, IQ_SHARED_TEMP, is created when you create or upgrade a database to SAP Sybase IQ 16.0. This dbspace stores temporary structures that are shared among nodes for distributed query processing.

Initially, this dbspace contains no files. To add files, use ALTER DBSPACE ADD FILE. Allocating files to this dbspace is optional and required only for distributed query processing in multiplex servers.

When you set the TEMP_DATA_IN_SHARED_TEMP logical server policy option ON, all temporary table data and eligible scratch data writes to the shared temporary store, provided that the shared temporary store is not empty. You must restart secondary nodes after setting this option or after adding a read-write file to the shared temporary store. If the shared temporary store contains no read-write file, or if you do not restart secondary nodes, data instead writes to IQ_SYSTEM_TEMP. When OFF, all temporary table data and scratch data writes to the local temporary store.

Shared System Temporary Store

A multiplex configuration with shared temporary storage can use the IQ_SHARED_TEMP dbspace as a shared system temporary store instead of requiring a separate local store for each secondary server. The shared system temporary store simplifies multiplex configuration, improves performance, and supports distributed query processing.

On multiplex systems:

When you set the logical server policy option TEMP_DATA_IN_SHARED_TEMP ON, SAP Sybase IQ creates all temporary objects on the IQ_SHARED_TEMP dbspace. You must restart secondary nodes after setting this option or after adding a read-write file to the shared temporary store. (If the shared temporary store contains no read-write file, or if you do not restart secondary nodes, data instead writes to IQ_SYSTEM_TEMP.)
Temporary user objects (such as tables or table indexes) that you create using the IN IQ_SYSTEM_TEMP clause go in either IQ_SYSTEM_TEMP or IQ_SHARED_TEMP, depending on the value of the logical server option TEMP_DATA_IN_SHARED_TEMP:
- If TEMP_DATA_IN_SHARED_TEMP is 'OFF', objects go in IQ_SYSTEM_TEMP.
- If TEMP_DATA_IN_SHARED_TEMP is set 'ON', objects go in IQ_SHARED_TEMP.
SAP Sybase IQ does not support creating temporary user objects using the IN IQ_SHARED_TEMP clause.
The WITH STOP SERVER clause automatically shuts down all servers in the logical server. These statements support WITH STOP SERVER:
- ALTER LOGICAL SERVER
- ALTER LS POLICY
- CREATE LOGICAL SERVER
- DROP LOGICAL SERVER
If you use ALTER LS POLICY ... WITH STOP SERVER to change the TEMP_DATA_IN_SHARED_TEMP option 'ON|OFF', all servers in that logical server shut down automatically. You must restart the servers to force the logical server to place temporary data in the store specified by the TEMP_DATA_IN_SHARED_TEMP option.
If you use ALTER LS POLICY to set TEMP_DATA_IN_SHARED_TEMP 'OFF', the logical server starts placing temporary data in the SYSTEM temporary area after the next normal server startup.
You can also change the TEMP_DATA_IN_SHARED_TEMP value indirectly using CREATE LOGICAL SERVER, ALTER LOGICAL SERVER, or DROP LOGICAL SERVER statements and the WITH STOP SERVER clause.