Patent ID: 7577658
Filing Date: 2009-08-18
Classification: G06F,Y10S

Abstract:
1. A database system including a processing unit and memory, comprising: a set of lock modes for use in locking a first key, a gap between the first key and a next key, and the combination of the first key and the gap in a B-tree index, the set of lock modes including: key shared (SØ) including a shared lock on the first key and no lock on the gap, gap shared (ØS) including no lock on the first key and a shared lock on the gap, key exclusive (XØ) including an exclusive lock on the first key and no lock on the gap, gap exclusive (ØX) including no lock on the first key and an exclusive lock on the gap, key shared gap exclusive (SX) including a shared lock on the first key and an exclusive lock on the gap, and key exclusive gap shared (XS) including an exclusive lock on the first key and a shared lock on the gap, wherein the set of lock modes enables concurrent operations by a first transaction and a second transaction that affect the first key and the gap.