MongoDB Documentation, Release 3.0.4 • 2.6.1 Changelog (page 846). • All issues closed in 2.6.1$^{667}$. The following changes in MongoDB affect both the standard and Enterprise editions: The aggregation pipeline adds the ability to return result sets of any size, either by returning a cursor or writing the output to a collection. Additionally, the aggregation pipeline supports variables and adds new operations to handle sets and redact data. Text search is now enabled by default, and the query system, including the aggregation pipeline $match stage, includes the $text operator, which resolves text-search queries. MongoDB 2.6 includes an updated text index (page 500) format and deprecates the text command. Improvements to the update and insert systems include additional operations and improvements that increase consis- tency of modified data. Text Search Integration Insert and Update Improvements Aggregation Enhancements Major Changes • The db.collection.aggregate() now returns a cursor, which enables the aggregation pipeline to return result sets of any size. • Aggregation pipelines now support an explain operation to aid analysis of aggregation operations. • Aggregation can now use a more efficient external-disk-based sorting process. • New pipeline stages: – $out stage to output to a collection. – $redact stage to allow additional control to accessing the data. • New or modified operators: – set expression operators . – $let and $map operators to allow for the use of variables. – $literal operator and $size operator. – $cond expression now accepts either an object or an array. • MongoDB preserves the order of the document fields following write operations except for the following cases: – The _id field is always the first field in the document. – Updates that include renaming of field names may result in the reordering of fields in the document. • New or enhanced update operators: – $bit operator supports bitwise xor operation. $^{667}$https://jira.mongodb.org/issues/?jql=fixVersion%20%3D%20%222.6.1%22%20AND%20project%20%3D%20SERVER 851 12.2. Previous Stable Releases