Query processor service
The single-phase commit query processor service is assigned to the QP service class. The task name for the QP service class is CACQP.
The query processor is the subcomponent of the Classic data server that processes SQL requests. The SQL requests can access a single database or file system or reference multiple types of databases or file systems.
The single-phase commit query processor accesses and joins information from multiple data sources and performs updates to a single data source.
The following table summarizes the configuration parameters that define query processor services in the QP service class.
| Parameter | Default value | Description |
|---|---|---|
| BTREEBUFFS | 4 | Number of in-memory B-tree buffer caches used before data is written out |
| CALLCAPTUREXITS | FALSE | Controls whether capture service system exits are called when accessing IMS or VSAM data |
| CPUGOVERNOR | None | CPU governor |
| IDLETIMEOUT | 5M | The amount of time that a service remains idle before it polls the local message queue for messages that are to be processed |
| INITIALTHREADS | 5 | Number of instances of this service that the region controller starts during initialization of the Classic data server |
| JOINTABLES | 4 | Join optimization |
| MAXROWSEXAMINED | 0 | Maximum rows examined |
| MAXROWSEXCACTION | 1 = RETURN | Maximum rows exceeded action |
| MAXROWSRETURNED | 0 | Maximum number of rows returned |
| MAXTHREADS | 10 | Maximum number of instances of this service that the region controller is allowed to start |
| MAXUSERS | 20 | Maximum number of user connections |
| RESPONSETIMEOUT | 5M | Maximum amount of time to wait for response before terminating a connection |
| SAFEXIT | None | System Authorization Facility (SAF) system exit |
| SEQBUFNO | 0 | Effective BUFNO value for a given file. |
| SEQBUFNOCALC | 0 | Method to use for determining the BUFNO value when accessing sequential files. |
| SEQUENCE | 0 | Sequence number that is assigned to services |
| SMFEXIT | None | System Management Facility (SMF) accounting exit that reports clock time and CPU time for a user session |
| STMTRETENTION | 0 = SYNCPOINT | Statement retention that defines the behavior of a prepared statement when a commit or rollback operation occurs |
| TEMPFILESPACE | HIPERSPACE,
INIT=8M, MAX=2048M, EXTEND=8M |
Temporary file space in megabytes |
| TRACELEVEL | 4 | Trace level |
| USERSUBPOOLMAX | 8192 | User pool maximum |
| VSAMAMPARMS | None | VSAM buffering information for VSAM files |
| WLMUOW | None | Workload Manager (WLM) unit of work activities |