Key-range locking with index trees

摘要: A database-management system (10) generates bounded-disorder indexes on its database keys. In such an index, the leaf nodes (51, 62) are large and divided into a number of buckets (52, 54, 56, 58), only one which ordinarily is accessed in any given single-record operation. The key values node distributed among node's accordance with hashing function. lockable ranges locked for scanning functions defined key-valued locking, each range bounded by successive that exist database. But multiple-bucket accesses would otherwise be required, because hash-function distribution several buckets, avoided sequence bucket rather than node. addition to existing values, moreover, buckets' key-value limits also employed bound ranges, even if no records contain those limits. This prevents end-of-bucket insertions deletions from needing further I/O operations order identify modify.