"When the heapallindexed argument to verification functions is true, an additional phase of verification is performed against the table associated with the target index relation. This consists of a “dummy” CREATE INDEX operation, which checks for the presence of all hypothetical new index tuples against a temporary, in-memory summarizing structure (this is built when needed during the basic first phase of verification). The summarizing structure “fingerprints” every tuple found within the target index. The high level principle behind heapallindexed verification is that a new index that is equivalent to the existing, target index must only have entries that can be found in the existing structure."
