Size the SQT Cache

Use the sqt_max_cache_size Replication Server configuration parameter and the dsi_sqt_max_cache_size database connection configuration parameter to size the SQT cache.

Monitor SQT cache usage by reviewing counter 24005 – CacheMemUsed. Instead, monitor counter 24009 – TransRemoved. If TransRemoved remains zero, indicating that transactions are not being flushed from the cache to make room for others, you may not need to adjust sqt_max_cache_size.

Warning! Setting the sqt_max_cache_size too high can cause the server to shutdown and can affect the overall resources of the Replication Server if the server memory_limit is not set high enough to accommodate the SQT cache sizing.

sqt_max_cache_size applies to all SQT caches supporting DIST clients, and provides a default value for SQT caches that support DSI clients. The DISTs can push through transactions rapidly; their SQT caches do not need to be as large as SQT caches for DSIs. Thus, it is advisable to set SQT cache sizes for DSIs individually using the connection configuration parameter dsi_sqt_max_cache_size, and using sqt_max_cache_size for DIST SQT caches only.

Note: In versions of Replication Server earlier than 15.5, setting sqt_max_cache_size too high can slow down replication. This advice does not apply to Replication Server 15.5 and later.