The section gives you information on the key features of memory guard and data model properties.
The full set of properties is listed in Configuring Memory Guard & Data Model Properties. The properties enable you to protect against out of memory errors and enhance data processing by setting controls such as:
Maximum data size for reports
Maximum data size for scheduled reports
SQL pruning for unused data set columns
Time out for SQL queries and also for reporting
The following section highlights some of the properties and provides detail on how the system responds to the settings:
By restricting the data size allowed for report processing you can prevent out of memory errors when a query returns more data than the system can handle.
Specify a Maximum Data Size Allowed for Online Processing
Property: Maximum report data size for online reports.
This property enables you to specify a maximum data size allowed for online report viewing. When you set a maximum data size, the following occurs when a user opens a report for online viewing:
A user submits a report to view online in the browser.
The data engine generates the data for the report.
Before document generation, the size of the data (in bytes) is inspected.
If the data generated is larger than the maximum setting, the report processing is ended. The user gets the following message:
The report you are trying to run exceeds the data limit set for this server. Either re-run with parameters that reduce the data or schedule this report. Contact your Administrator if you have questions.
The user can then either set parameters (if available for the report) to limit the data and resubmit online; or use the BI Publisher scheduler to submit the report.
The default value for this property is 300 MB.
Specify a Maximum Data Size Allowed for Offline (Scheduled Report) Processing
Property: Maximum report data size for offline (scheduled) reports.
This feature enables you to specify a maximum data size allowed for scheduled reports. When you set a maximum data size, the following occurs when a scheduled report job executes:
The scheduler commences processing of a report job.
The data engine generates the data for the report.
If the data generated is larger than the maximum setting, the report processing is ended. The scheduled report job fails with the following status message:
Report data size exceeds the maximum limit (<nnn> bytes). Stopped processing.
The user can then set parameters (if available for the report) to limit the data.
The default value for this property is 500 MB.
This set of properties helps you to protect against out of memory conditions by establishing a minimum available free memory space.
This set of properties enables your system to automatically protect free memory availability and intelligently process reports with large data sets based on this availability.
Specify A Minimum Free Memory Threshold for Report Processing
Specify Maximum Report Data Size Under the Free Memory Threshold
Set Maximum Wait Time for Free Memory to Come Back Above the Threshold
Specify A Minimum Free Memory Threshold for Report Processing
Property: Free memory threshold
This setting enables you to specify a minimum value for free JVM space. This enables you to control whether to run a report based on two factors: current usage and the size of the report data. This feature requires the setting of several properties that work together. You specify the threshold JVM space, the report maximum report size that will be allowed when the JVM falls below the threshold, and the maximum wait time to pause the report to wait for more JVM free space to become available.
When you set these properties, the following occurs when a user opens a report for online viewing:
A user submits a report to view online in the browser.
The data engine generates the data for the report.
JVM memory is inspected. If the available JVM memory is above the Free memory threshold property value, the report processes as usual and there is no system intervention.
If the available JVM memory is below the threshold value, the size of the report data is inspected and compared to the property setting for Maximum report data size under the free memory threshold. If the report data is below this threshold, then the report continues processing.
If the report data size exceeds the threshold, then the report is paused to wait for free memory to become available. The report will wait for the time specified in the property Maximum Wait Time for Free Memory to Come Back Above Threshold Value. If the free memory does not rise back above the minimum in the wait period specified, the report request is rejected.
The default value for this property is 500 MB.
Specify Maximum Report Data Size Under the Free Memory Threshold
Property: Maximum report data size under the free memory threshold
Default value: (value of Free Memory Threshold)/10
Maximum single report data size allowed when free JVM memory is under the specified threshold value set in Free memory threshold. For example (assuming the default setting), if the data generated for a single report exceeds one-tenth of the value set for Free memory threshold, then processing is terminated. Therefore if the Free memory threshold is set to 100 MB and a single report data extract exceeds 10 MB, then the report processing is terminated.
This property takes effect only when Free memory threshold is set to be a positive value.
Set Minimum Time Span Between Garbage Collection Runs
Minimum time span in seconds between any two subsequent garbage collection runs. Set this value to avoid overrunning JVM garbage collection. The server enforces the minimum of 120 seconds, which means the value will be reset to 120 seconds if it falls below the minimum.
The default is 300 seconds.
Set Maximum Wait Time for Free Memory to Come Back Above the Threshold
The maximum time in seconds that a run-report request will wait for free JVM memory to come back above the threshold value. This property value takes effect only when a positive value for Free memory threshold is specified.
If the free memory becomes available within the time specified, the request will proceed immediately to generate the document. If free memory is still below the threshold value after the time specified, the request is rejected. For online requests, the larger this property value, the longer the browser will wait for a request to run.
The default for this property is 30 seconds.
The data engine property settings provide additional points to protect your system against out of memory errors.
These include:
Set Maximum Data Size That Can Be Generated by the Data Engine
This property is used only when you generate XML data via data model editor. In a normal report generation scenario, since template is chosen always, memory guard side properties (maximum report data size for online/offline for each template type) take precedence over this property.
Setting maximum data size sets an absolute limit to the data that can be generated from the execution of a data model. This setting applies to both online report requests and to requests submitted through the scheduler. When the size of the file generated by the data engine exceeds the limit, the data engine terminates execution of the data model and throws the exception:
"oracle.xdo.dataengine.diagnostic.XMLSizeLimitException: XML Output (NNNNNNbytes) generated exceeds specified file size limit (NNNNNbytes)..!!!!!!!".
If the report request was submitted through the scheduler, the job will show as failed in the Report Job History page. The exception error noted above displays when you rest your cursor over the status. If the report request was submitted online, the user will get the error "Unable to retrieve the data XML."
Set Maximum Sample Data Size
A sample data set is required for all data models. The sample data is used during template design. Sample data can be generated by the data model editor or uploaded to the data model. Large sample data sets can impact the performance of the design tools.
Set this property to limit the size of the sample data file that can be uploaded to the data model.
Set Automatic Database Fetch Size
This setting calculates and sets database fetch size at run time depending on total number of data set columns and total number of query columns. Setting this property will override the server-level and data model-level database fetch size properties. When set, this property takes effect for all data models and can significantly slow processing time. This setting is recommended for implementations of BI Publisher that frequently process complex queries of hundreds of columns, such as Oracle Fusion Applications implementations. This setting is not recommended for most general implementations of BI Publisher.