For plugin startup and for error handling situations is necessary to have fallback from psearch to normal LDAP query mode (and then back to psearch).

If some problem inside psearch occurs:

• switch to normal query mode
• flush and repopulate caches from LDAP DB
• then switch back to psearch mode

While plugin starts:

• psearch dumps whole LDAP DB to plugin's cache.
• In meanwhile use normal queries to answer client requests.

Dumping can be be pretty long operation, if database is large. It's something between several seconds to two minutes or so, it depends.