1 /* 2 package bbolt implements a low-level key/value store in pure Go. It supports 3 fully serializable transactions, ACID semantics, and lock-free MVCC with 4 multiple readers and a single writer. Bolt can be used for projects that 5 want a simple data store without the need to add large dependencies such as 6 Postgres or MySQL. 7 8 Bolt is a single-level, zero-copy, B+tree data store. This means that Bolt is 9 optimized for fast read access and does not require recovery in the event of a 10 system crash. Transactions which have not finished committing will simply be 11 rolled back in the event of a crash. 12 13 The design of Bolt is based on Howard Chu's LMDB database project. 14 15 Bolt currently works on Windows, Mac OS X, and Linux. 16 17 # Basics 18 19 There are only a few types in Bolt: DB, Bucket, Tx, and Cursor. The DB is 20 a collection of buckets and is represented by a single file on disk. A bucket is 21 a collection of unique keys that are associated with values. 22 23 Transactions provide either read-only or read-write access to the database. 24 Read-only transactions can retrieve key/value pairs and can use Cursors to 25 iterate over the dataset sequentially. Read-write transactions can create and 26 delete buckets and can insert and remove keys. Only one read-write transaction 27 is allowed at a time. 28 29 # Caveats 30 31 The database uses a read-only, memory-mapped data file to ensure that 32 applications cannot corrupt the database, however, this means that keys and 33 values returned from Bolt cannot be changed. Writing to a read-only byte slice 34 will cause Go to panic. 35 36 Keys and values retrieved from the database are only valid for the life of 37 the transaction. When used outside the transaction, these byte slices can 38 point to different data or can point to invalid memory which will cause a panic. 39 */ 40 package bbolt 41