1. A query processing method, performed by a search engine server system, comprising: receiving, from a client system distinct from the search engine server system, a search query having one or more query terms; in response to receiving the search query: identifying a set of search result documents in accordance with the search query; generating a content snippet corresponding to content in a respective document of the identified set of search result documents, the content snippet associated with at least one query term of the one or more query terms in the search query; and returning to the client system a response to the search query, the response including information identifying at least the respective search result document and including the content snippet of the respective search result document; wherein generating the content snippet comprises: receiving a set of first token identifiers, comprising compressed content of the respective search result document, from a compressed document repository; performing a first decompression operation by applying one or more first mappings to the set of first token identifiers to provide a set of second token identifiers; and performing a second decompression operation by applying a second mapping to the set of second token identifiers to recover uncompressed content comprising a portion of the respective document; wherein the first decompression operation produces a respective second token identifier for each first token identifier, the set of second token identifiers has a same number of distinct token identifiers as the first set of token identifiers, and the second decompression operation produces a respective uncompressed content item for each second token identifier; and wherein each first token identifier comprises an M bit integer value, and each second token identifier comprises an N bit integer value, N and M are positive integers and N is greater than M.