In rare cases, due to a problem in the Java 6 JDK, if you are using multiplexed routing under extremely heavy load, Oracle ATG Web Commerce Search may throw a Null Pointer Exception. If this happens, your error logs will contain this message:

This server is under too much load for the multiplexed strategy on
Windows. This is a known problem with Sun's JDK (sun bug 5076772); reduce
load IMMEDIATELY or switch to searchStrategy=serialized.

Multiplexed and serialized are options used by search routing to optimize handling of multi-partition indexes. If using the multiplexed strategy (the default for a multi-partition index), routing addresses all search engines simultaneously. If using the serialized strategy, routing contacts engines one after another.

To change your routing strategy to serialized, create a Configuration.properties file in /atg/servername/localconfig/atg/search/routing with this line:

strategyType=serialized

Then rebuild and redeploy your Oracle ATG Web Commerce application EAR file.