8. A system in communication, comprising: a processor; and a computer readable storage medium including code executed by the processor to perform operations, the operations comprising: accessing document identifiers for documents including at least one value that is a member of a set of values; generating a number of posting lists associated with a first level, wherein each posting list is associated with a range of consecutive values within the set of values and includes document identifiers for documents including at least one value within the range of consecutive values associated with the posting list, and wherein each document identifier is associated with one value in the set of values included in the document identified by the document identifier; performing at least one iteration of generating posting lists for an additional level, wherein each posting list generated for the additional level is formed by merging at least two posting lists associated with a previous level, wherein each generated posting list at one additional level is associated with consecutive values in the set of values, wherein each document in the generated posting list at the additional level includes one value in the consecutive values associated with the posting list at the additional level, and wherein a new additional level and posting lists associated therewith are generated with each iteration; receiving a query on a query range of values within the set of values; determining a minimum number of posting lists associated with one or more levels having consecutive values that include the query range of values; merging the determined posting lists to form a merged posting list including document identifiers of documents including values within the query range; and returning the document identifiers in the merged posting list.
13. The system of claim 8 , wherein the additional iterations are performed to generate posting lists for a number of levels.