This is a document for PGroonga 2.X and 3.X. See PGroonga 1.x document when you're using old PGroonga.
pgroonga.match_escalation_threshold parameterpgroonga.match_escalation_threshold parameter controls when match escalation is occurred.
Match escalation is auto loose search. If the number of matched records is equal or less than the threshold specified by pgroonga.match_escalation_threshold parameter, loose search is done automatically. It's match escalation.
The default threshold is 0. It means that no records are matched, loose search is done automatically.
You can disable match escalation by specifying -1.
Normally, you don't need to change this parameter. Auto loose search is useful for users.
See also pgroonga.force_match_escalation parameter.
In SQL:
SET pgroonga.match_escalation_threshold = threshold;
In postgresql.conf:
pgroonga.match_escalation_threshold = threshold
threshold is a number value.
Here is an example to disable match escalation:
SET pgroonga.match_escalation_threshold = -1;