Embodiments are directed towards receiving and processing search queries directed towards relatively large sets of data. The data is stored in a record based datastore. From the stored data, field names, corresponding field values, and posting values may be determined. Posting values may be employed to locate records in the datastore that include the field names and field values. The field names, field values, and posting values may be employed to generate a lexicon. If queries are received, a lexicon query processor may employ the lexicon separate from the datastore to generate responses to the received queries. Queries may include clauses that may be processed using the lexicon separate from the datastore, such as, where clause expressions, group-by clause expressions, aggregation functions, or the like. A time values array may be used to enable queries to process group-by-time expressions that may return results grouped into sub-sets based on time ranges.