Addressing web service response time delays in IBM Business Process Manager Advanced V8.x
Nakul Bharade 270004XHV7 Visits (1938)
This blog covers the solution to response time delays that may be seen with web service calls in IBM Business Process Manager Advanced V8.x. The problem and its solution that are discussed in this blog apply to IBM Business Process Manager Advanced topology that is configured with DB2.
As covered in Martin and Geza's article Para
With Assured Persistent QoS, comes a significant overhead of database transactions to the messaging database on each outbound web service request. This leads to increased database logging activity. Now, if the messaging database is set up for log archiving, with each log archiving event, the database log manager searches the history file (db2rhist.asc) for when the log was generated. It searches the file in order to update the entry with when the log is being archived as well as where it is being archived. The larger the size of this history file, the longer it takes for the log manager to search for an appropriate log entry in this file. As the log manager searches for the right entry, it holds a lock on the history file. While the log manager holds this lock, it precludes the log writer from updating the history file with an entry for a new log file. Commit and rollback activity, and possibly other database operations, are blocked until the log writer can add the history file entry and continue normal processing. The blocked log writer leads to response time spikes, which are seen in the previous response time graph.
To mitigate this issue, it is important that the size of the history file is managed appropriately. Typically, it is recommended that the history file size must not exceed 4MB. Following factors should be considered in order to limit the size of the history file:
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