extract all clauses from a conjunction query.
When clauses from a conjunction are extracted the number of clauses is
also stored in an internal doc values field (minimum_should_match field).
This field is used by the CoveringQuery and allows the percolator to
reduce the number of false positives when selecting candidate matches and
in certain cases be absolutely sure that a conjunction candidate match
will match and then skip MemoryIndex validation. This can greatly improve
performance.
Before this change only a single clause was extracted from a conjunction
query. The percolator tried to extract the clauses that was rarest in order
(based on term length) to attempt less candidate queries to be selected
in the first place. However this still method there is still a very high
chance that candidate query matches are false positives.
This change also removes the influencing query extraction added via #26081
as this is no longer needed because now all conjunction clauses are extracted.
https://www.elastic.co/guide/en/elasticsearch/reference/6.x/percolator.html#_influencing_query_extractionCloses#26307
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