Concurrent Query Execution
By default, IBM® Cognos® software executes queries in a report sequentially. You can do this by setting advanced server properties for the report service, the batch report service, or both. When concurrent query execution is enabled, the report server determines which queries in the report can be run concurrently.
The report author must specify the queries in a report that are candidates for concurrent execution. For more information, see the IBM Cognos Report Studio User Guide.
RSVP.CONCURRENTQUERY.NUMHELPERSPERPROCESS
Use this parameter to enable concurrent query execution and set the maximum number of query execution helpers for each report service or batch report service process.
The default value is 0, meaning that the concurrent query execution disabled.
Each query execution helper results in an additional data source connection. For example, a report service has four processes with two high affinity connections and two low affinity connections:
- If the maximum number of query execution helpers is set to 0 (disabled), the maximum number of data source connections created by the report service is 16 (two low affinity connections plus two high affinity connections plus zero query execution helpers times four processes).
- If the maximum number of query execution helpers is set to 2, the maximum number of data source connections created by the report service is 24 (two low affinity connections plus two high affinity connections plus two query execution helpers times four processes).
RSVP.CONCURRENTQUERY.MAXNUMHELPERSPERREPORT
Use this parameter to specify the maximum number of query execution helpers for each report. This parameter is used to prevent a single report from consuming all available query execution helpers.
For example, a report has eight queries that can run concurrently:
- If RSVP.CONCURRENTQUERY.NUMHELPERSPERPROCESS and RSVP.CONCURRENTQUERY.MAXNUMHELPERSPERREPORT are both set to four, the report consumes all query helpers when executed. No other report is able to run queries concurrently until the report has finished executing.
- If RSVP.CONCURRENTQUERY.MAXNUMHELPERSPERREPORT is set to two instead, the report consumes two query helpers, leaving two for other reports to use.
The default value for this parameter is 1.
This setting has no effect unless RSVP.CONCURRENTQUERY.NUMHELPERSPERPROCESS is set to greater than 0.
RSVP.CONCURRENTQUERY.ENABLEDFORINTERACTIVEOUTPUT
Use this parameter to enable concurrent query execution when the report service is producing interactive output.
For interactive reports, if concurrent query execution is enabled, some queries may be unnecessarily executed because the results are not used. For example, all the queries for a multi-page report may execute with at least one query on each page, but the user may view only the first page. If you do not want to use resources for results that are not used in interactive reports, disable this parameter.
Authored prompt pages are not interactive output and are not affected by this setting.
The default value for this parameter is false, meaning disabled.
RSVP.PROMPT.EFFECTIVEPROMPTINFO.IGNORE
Use this parameter to disable the issuing of effectivePromptInfo attribute in metadata requests and effectively disable moving the prompt information from under the caption attribute of a level to the level itself.
The default value for this parameter is false, meaning disabled.