This is a document for PGroonga 2.0.0 or later. See PGroonga 1.X document when you're using PGroonga 1.X.
pgroonga_crash_safer.max_recovery_threads parameterSince 3.1.9.
pgroonga_crash_safer.max_recovery_threads parameter specifies the number of threads for recovery of broken Groonga indexes.
0: The default. It disables parallel recovery.
-1: Use the all CPUs in the environment.
1 or larger: Use the specified number of CPUs.
In postgresql.conf:
pgroonga_crash_safer.max_recovery_threads = number_of_threads
Here is an example to specify -1 to use all available CPUs:
pgroonga_crash_safer.max_recovery_threads = -1