If you have a large number of LDAP entries or a slow LDAP connection, you can preload your directory caches to prevent mail from backing up in the system during the initial directory cache building process. Under most circumstances, cache preload is not necessary because the caches can be built gradually during the normal course of operation with satisfactory system performance.
Cache preload is performed on a per-function basis and is supported for the following functions:
Quarantine address resolution
For all functions except routing, a single input file populates all data sources that are enabled for that function. For routing, a separate input file is required to populate each data source.
If you disable a data source, the cache for all enabled functions for that data source is cleared. If you create a new data source or enable a disabled data source you must preload the caches again.