Increasing RAPCache Subscriber Message-Loading Performance

Improve message-loading performance of the RAPCache subscriber.

Note: Sybase recommends that the subscriber configuration directory that contains the XML-based message template definitions (for example, <RAP>/RAPCacheSubscriber/templates) should contain only definitions for the messages that are being loaded by the subscriber into the RAPCache database. This is because the RAPCache subscriber allocates database connections and other system resources for processing each message definition template. Remove the extraneous message template definition files to prevent the allocation of these resources.

RAPCache subscriber configuration
Parameters	Description
TDS Packet Size	The TDS packet size affects the maximum size of the packets that are transmitted between the RAPCache subscriber and RAPCache database. Larger values (8K or 16K) reduce network communication overhead between the subscriber and the RAPCache, and thus help improve system performance.
Bulk Insert Array Size	Affects the amount of buffer that the RAPCache subscriber uses before transferring data to the RAPCache. Large values for this parameter, with a large TDS packet size can result in reduced network overhead between the RAPCache and the subscriber. The value set for this parameter is constrained by overall system memory.
Bulk Batch Size	Information loaded into the RAPCache is periodically committed to the database and made available to readers. The bulk batch size controls how much information can be loaded into the RAPCache before it is committed. Higher values increase system latency, and require a larger number of locks in the RAPCache to accommodate larger database transactions. Smaller values for this parameter introduce the extra overhead of frequently committing transactions to the database and result in slower load performance.
Idle Buffer Write Delay	Determines the number of milliseconds to wait before data is transferred to the RAPCache when the system is not receiving data from the publisher. Low values of this parameter ensure lower system latency in periods where the data flow is not steady.
Buffer Age Limit	Determines the number of milliseconds to wait before data is transferred to the RAPCache when the system is receiving a relatively small amount of data from the publisher at very low frequencies, for example, if one message is received every second. Low values of the buffer age limit ensure lower system latency in periods where the data flow is at a low rate.