Troubleshooting
Problem
As of 11.0.3, the processing of datafiles changed. Before uploaded files were stored directly to the file system. The location is defined in Cognos Configuration, Environment > Data files location.
However as of 11.0.3, uploaded files are stored in Cognos content store. Full details can be found in this blog:
https://community.ibm.com/community/user/businessanalytics/blogs/kevin-mcfaul/2016/08/17/where-is-data-uploaded-into-cognos-analytics-stored
As detailed in the blog, even when the data is stored in the content store or an external object store, it will be automatically extracted to temporary file locations on the Application Tier Component servers when it is being used in dashboards and reports. The default location for these temporary data files is the Data file location defined in Cognos configuration.So how does this work in a distributed environment with multiple dispatchers? Do you need to set a network path/shared location?
Resolving The Problem
You don't need to use a shared network location anymore. Prior to 11.0.3 you did need to use a shared network location so all the dispatchers would have access to the datafiles.
However in 11.0.3 and later versions, the best option is to leave the default location (CA install\data).
Changing the default location to a shared network may hurt performance if access to that location is slower than having each dispatcher storing a local copy.
In Windows environments you may also find issues using UNC paths. This is due to restriction imposed by Hadoop libraries used in this feature.
If you still want to use a shared location and you are on a Windows environment, use a symbolic link instead (see https://www-01.ibm.com/support/docview.wss?uid=swg21980560)
The default configuration will dynamically store a copy of the data on the dispatcher running the query. A dispatcher that never receives a query against the data will not download it from the CM.
If the data file already exists in a dispatcher's cache, that dispatcher will not download the data from the content store again.
The data file will be cleared from cache if it is not queried within one week. This time is configurable, but the data file cannot be deleted immediately after a query.
Related Information
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Document Information
Modified date:
17 May 2021
UID
ibm10792287