See Top Children Query
QueryBuilder qb = topChildrenQuery( "blog_tag", termQuery("tag", "something") ) .score("max") .factor(5) .incrementalFactor(2);
field
query
max, sum or avg
max
sum
avg
how many hits are asked for in the first child query run (defaults to 5)
if not enough parents are found, and there are still more child docs to query, then the child search hits are expanded by multiplying by the incremental_factor (defaults to 2).