Oracle: bitmap index and deadlock-2

Oracle: bitmap index and deadlock-2 The bitmap index is stored as a compressed index value, which contains a ROWID in the range, therefore, ORACLE must lock the ROWID in all ranges for a given value. Row-level locking is not supported. Another method: When a bitmap index is used, a key points to multiple rows (hundreds of rows). If a bitmap index key is updated, the bitmap index fields corresponding to other rows are locked at the same time! Compared with B-Tree indexes, www.2cto.com stores bitmaps in a compressed format. Therefore, the occupied disk space is much smaller than that of B-Tree indexes. Disadvantages: this lock is costly and may cause some DML statements to have a "lock wait", which seriously affects the efficiency of insertion, update, and deletion. It is not applicable to high-concurrency systems. Usage principle of Bitmap indexes: Bitmap indexes are mainly used to support system or static data and do not support row-level locking of indexes.