The event buffers per engine Adaptive Server configuration parameter specifies the maximum number of events to be buffered per engine. The default is 100, a number which most users will need to increase. Trade-offs are involved in selecting an optimal buffer size, since a low number forces more frequent scans by the Monitor Server, but a large buffer size reduces the amount of memory available for other uses, such as procedure cache.
You should balance the possibility of event loss against the memory costs of a large number of event buffers. The following calculation determines how much Adaptive Server memory your setting will use:
Adaptive Server = 100 bytes * number of * number of memory (bytes) event buffers active engines
The recommended procedure is to first reset the event buffer size to a somewhat larger number. A size of 2000 usually is large enough to avoid event buffer overruns.
For very active servers, you may need to set this parameter to a considerably higher number to avoid event loss.
You may want to increase the event buffer size beyond the minimum size that prevents overruns because larger event buffers decrease the frequency of scans by Monitor Server.