Amit,
When pulling data, it is Async : - SF -> PI -> Target.
We can also perform a lookup/query on SF. It is Sync : - Source <-> PI <-> SF. XML for this is
<?xml version='1.0' encoding='utf-8'?><urn:query xmlns:urn='urn:sfobject.sfapi.successfactors.com'><urn:queryString>SELECT person, personal_information FROM CompoundEmployee</urn:queryString></urn:query>