System Tables Caching

System metadata table caching allows for improving system performance and speeding up opening of complex reports that use a number of data sources in the web application by reducing the time of reading system tables from database. Each startup of BI server process is accompanied with creating a cache for a specific process.

IMPORTANT. System metadata table caching is allowed only in the production version. When caching is used, data in system metadata tables must not be changed.

Cache includes metadata system tables, which contents can be set up.

Cache is stored in RAM and used during repository login and while working with objects. Cache is local for BI server and is global for active sessions within the running BI server process. If a BI server cluster is used, cache is created for each cluster's work node and is not synchronized with each other.

Creating a cache requires the ADMIN scheme owner or the user with system table read permissions.

Cache update without BI server restart is available only via Fore.

To force clear system table cache during BI server work, use methods of the IMetabaseManager interface. If BI server is stopped or restarted, cache is reset automatically, additional cache clearing is not needed.

NOTE. To set up system metadata table caching, see or contact the technical support by sending an email at support@fsight.ru or via technical support services, which are available after registration at the website.

Caching constraints:

Memory volume for BLOB data in each table is limited to 256 MB, and each value should not exceed 16 MB. If the current BLOB value exceeds 16 Mb, the current record is skipped and will be read from the database. If the total volume of BLOB memory exceeds 256 Mb the current table stops to be written to cache. Corresponding messages are displayed in the MBCACHE category in debug info:
Starting of the Apache2 web server, on which the BI server is installed, may be interrupted due to process timeouts determined in the operating system. To ensure correct caching, increase startup timeout values.