Oracle ATG Web Commerce Search automatically balances load across your engines. If you suspect your search engines may be under- or over-utilized, you can check values in the search response XML.

<answer ... maxThreads="10" loadFactor="0.10" throughputQps="0.13"
avgResponseTimeMs="74.60" expectedResponseTimeMs="149.21">

The loadFactor value provides a summary of search engine load. The formula for calculating the loadFactor is:

(request_queue_length + active_threads) / max_active_threads

A load factor greater than 1 means that the engine is overloaded at the time of the request. Load information is periodically logged.

The throughputQps (queries per second), avgResponseTimes, and expectedResponseTimes can also provide information on how well the server is performing.

If you have reason to be concerned about your search server load, you can adjust the settings used to control how often load information is recorded in the search logs. To change this setting, configure the PerformanceLoggingPeriod element in the AEConfig.xml file located in <ATG10dir>/Search10/SearchEngine/platform/bin. For example:

<PerformanceLoggingPeriod>600</PerformanceLoggingPeriod>

The default is to log every 10 minutes.