The default value is 104,857,600 (100MB). For more information about failure-directed search see parameter CP.IntParam.FailureDirectedSearch.

Failure-directed search can sometimes consume a lot of memory, especially when end times of interval variables are not bounded. Therefore it is usually not started immediately, but only when the effective horizon (time period over which CP Optimizer must reason) becomes small enough for failure-directed search to operate inside the memory limit specified by this parameter. For many types of scheduling problems, the effective horizon tends to reduce when CP Optimizer finds a better solution (often most significantly when the initial solution is found). Therefore, when each new solution is found, CP Optimizer decides whether or not to turn on failure-directed search.

Note that this parameter does not influence the effectiveness of failure-directed search, once started. Its purpose is only to control the point at which failure-directed search will begin to function.