public long getBackgroundFrequency(BytesRef termBytes) {
assert termsEnum
!= null; // having failed to find a field in the index we don't expect any calls for
// frequencies
long result = 0;
try {
if (termsEnum.seekExact(termBytes)) {
result = termsEnum.docFreq();
}
} catch (IOException e) {
throw new ElasticsearchException("IOException loading background document frequency info", e);
}
return result;
}
/**
* Creates the TermsEnum (if not already created) and must be called before any calls to
* getBackgroundFrequency
*
* @param context The aggregation context
* @return The number of documents in the index (after an optional filter might have been applied)
*/
public long prepareBackground(AggregationContext context) {
if (termsEnum != null) {
// already prepared - return
return termsEnum.getNumDocs();
}
SearchContext searchContext = context.searchContext();
IndexReader reader = searchContext.searcher().getIndexReader();
try {
if (numberOfAggregatorsCreated == 1) {
// Setup a termsEnum for sole use by one aggregator
termsEnum = new FilterableTermsEnum(reader, indexedFieldName, PostingsEnum.NONE, filter);
} else {
// When we have > 1 agg we have possibility of duplicate term frequency lookups
// and so use a TermsEnum that caches results of all term lookups
termsEnum =
new FreqTermsEnum(
reader, indexedFieldName, true, false, filter, searchContext.bigArrays());
}
} catch (IOException e) {
throw new ElasticsearchException("failed to build terms enumeration", e);
}
return termsEnum.getNumDocs();
}