MetaMatrix System
MetaMatrix Query Configuration Properties
The following configuration properties control the execution of MetaMatrix Query. These properties are stored in the file referenced by the dqp.configFile property, defined in the bootstrap properties file.
These properties can be manipulated using the Administrative API. Note however that updated properties do not take effect until the query engine is re-started.
Processor Properties
These properties control query processing.
| Property | Description | Type | Default |
|---|---|---|---|
| ProcessPoolMaxThreads | Process pool maximum thread count. | integer | 64 |
| ProcessPoolThreadTTL | The maximum length of time a processor pool thread may live in idle state, in milliseconds. | integer - millisec | 120000 |
| ProcessorTimeslice | Query processor time slice, in milliseconds. | integer - millisec | 2000 |
| MinFetchSize | Minimum allowed fetch size, set via JDBC. User requested value ignored below this value. | integer | 100 |
| MaxFetchSize | Maximum allowed fetch size, set via JDBC. User requested value ignored above this value. | integer | 20000 |
| MaxPlanCacheSize | The maximum number of query plans that are cached. | integer | 100 |
Buffer Manager Properties
These properties are related to the MetaMatrix buffer manager. All these properties begin with the prefix "dqp.buffer".
| Property | Description | Type | Default |
|---|---|---|---|
| connectorBatchSize | The max size of a batch sent between connector and query service. Should be even multiple of processorBatchSize. |
integer | 2000 |
| processorBatchSize | The max size of a batch sent internally within the query processor. Should be <= the connectorBatchSize. |
integer | 2000 |
| useDisk | Defines whether to use disk buffering or not. | boolean | true |
| dir | The location to store temporary buffers too large to fit in memory. If this is not defined, the user's temp directory will be used. | string | ./buffer |
| memory | The numeric memory size in MB, to be used before disk buffering kicks in | integer - MB | 64 |
Caching Properties
These properties control caching in the MetaMatrix query engine.
| Property | Description | Type | Default |
|---|---|---|---|
| MaxCodeTables | Maximum number of cached code tables. | integer | 50 |
| MaxCodeTableRecords | Maximum number of records in ALL code tables, combined. | integer | 10000 |
| ResultSetCacheEnabled | Denotes whether or not result set caching is enabled. | integer | 0 (not enabled) |
| ResultSetCacheSize | The maximum size the result set cache will be allowed to grow to before objects are removed. | integer - MB | 0 (no limit) |
| ResultSetCacheMaxAge | The maximum time a result set will be kept in cache before being automatically cleared. | integer - millisec | 0 (no limit) |
| ResultSetCacheScope | Defines whether caching is restricted to a specific session (‘session’) or a specific VDB version (‘vdb’). | string | vdb |
Common Connector Properties
These properties are common to all connectors.
| Property | Description | Type | Default |
|---|---|---|---|
| ConnectorBindingName | The name of the connector binding. Must be unique across all connector bindings. This property is not editable, and is not seen in the Designer in the connector properties table. | string | |
| ConnectorClass | The class name of the custom connector class that connects to the data source. Required. Not editable. | string | |
| ConnectorClassPath | The class path of the custom connector class that connects to the data source. Required. | string | |
| ConnectorMaxThreads | The maximum number of connector worker threads. Required. | integer | |
| ConnectorThreadTTL | The maximum length of time a connector thread may live in idle state. Required. | integer - milliseconds | |
| ExceptionOnMaxRows | Specifies whether or not an exception is thrown when the number of rows for a query exceeds the value of MaxResultRows. If this flag is set to false, then no more rows than MaxResultRows will be returned, but no exception will be thrown. | boolean | |
| MaxResultRows | The maximum number of rows to be processed by the connector from a source. A custom connector should stop adding rows to the ResultsCollector when the number of rows reaches this value. Optional – if not specified, all rows will be processed. | integer |