Tamino has about 30 database parameters, some of which influence overall performance. In the following table, you will find a short description of the parameters that influence performance and recommendations about how to set them. For a general description of database parameters, see Tamino Manager, Creating a Database.
| Name | Description/Performance |
|---|---|
| Server Properties | |
| Buffer pool size | This is the size of the buffer pool of the Tamino
Server. The higher this value is set, the shorter the I/O waiting times. The
maximum should not exceed the size of physical memory in order to avoid
swapping (keep other memory consuming resources in mind!). If Tamino starts
receiving regular page faults, the value is probably too high compared to the
size of the physical memory.
Tip: |
| Dynamic pool size | This is the size of the internal dynamic working pool of the Tamino server. It is used to keep result sets and for sorting. If this parameter is set too low, information will be written to temporary working space which leads to disk I/O. |
| Request log file maximum size | XML request logging may degrade performance to a small extent. Hence, performance data gained from XML request logging should be handled with care. |
| XML Properties | |
| XML work threads (XWT) | This is the number of threads used to process XML commands, which can be processed in parallel. If no XWT is available (too many parallel requests), the request will be kept in a queue. The thread is busy until the result is sent or an error occurs. If the value is too high, the threads may impede each other. On the other hand, if the value is too low, applications doing updates may become too slow due to locking. |
| Word fragment index |
This specifies whether Tamino should create a word fragment index
when the search type is set for text indexing. This accelerates the resolution
of queries involving text strings such as The index can be switched on and off with the Tamino Manager. The change is effective from the next start of the Tamino server. Note that switching on this parameter for a database that already contains data will result in very long startup times for the first server start after the enabling of the index. If you switch the word fragment index on or off, we recommend that you shut down and start up the database and then take a backup before you make any content changes to the database. |
| XML maximum request duration |
The maximum duration of each request is limited to the specified number of seconds. If a request takes longer than the limit that is specified with this parameter, the request will be aborted, and an error message is returned. |
| XQuery document cache size | This parameter defines the capacity of the document cache that is used for XQuery processing for each request. Document caching improves the performance of certain queries like join queries or sort-by queries where the sorting is not done via an index. Also certain XQuery update statements can benefit from a big document cache. The capacity of the XQuery document cache is specified in MB. The default capacity is 20 MB. For applications with a high parallel query load it may be necessary to reduce the parameter. |
