| Event | Serialization/synchronization of |
enq: BF - contention | Access to a bloom filter in a parallel statement. See also init parameter _bloom_pruning_enabled |
enq: CF - contention | Read and write transactions on a controlfile. |
enq: DW - contention | Acquiring the In-Memory Dispenser Latch (Securfile LOBs) |
enq: DX - contention | Distributed transactions |
enq: FB - contention | Block formatting (at most one process can format a block at a time) |
enq: HW - contention | Allocation of space beyond the high water mark of a segment. |
enq: PS - contention | Reservation and synchronization of parallel execution server processes. |
enq: RO - fast object reuse | Operations between foreground process and a background process such as DBWR or CKPT. (aka multiple object reuse). Typically used when objects are dropped or tables are truncated. |
enq: SQ - contention | Access to sequences. |
enq: SS - contention | Access to sort segments. |
enq: ST - contention | Space management of dictionary managed tablespaces |
enq: TO - contention | Access to temporary table objects |
enq: TS - contention | Temporary segment or bitmap tablespace. |
enq: TT - contention | Tablespace operations |
enq: US - contention | Some operations on rollback segments. Always acquired in exclusive mode. |