Why are children of the and-filter cached?

According to


filters inside an and-filter don't use a BitSet but only check the
conditions inside the iterated documents.

When I look at the explanation of

GET megacorp/employee/_search?explain=1
{
"query": {
"filtered": {
"filter": {
"and": [
{ "term": { "age": "25" } },
{ "term": { "last_name": "smith" } }
]
}
}
}
}

it says:

"_explanation": {
"value": 1,
"description": "ConstantScore(+cache(age:[25 TO 25])
+cache(last_name:smith)), product of:",
"details": [
{ "value": 1, "description": "boost" }, { "value": 1, "description":
"queryNorm" }
]
}

What does that "cache()" actually mean and how is it beneficial to check
conditions in each document?

--
You received this message because you are subscribed to the Google Groups "elasticsearch" group.
To unsubscribe from this group and stop receiving emails from it, send an email to elasticsearch+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/5d020da5-f1ea-4250-adc7-50a0efe77db1%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.