有时候看到数据库报告中的enq:xxx不知道什么意思，现在列出来以供参考。
| enq: AD – allocate AU@H_301_11@ | Synchronizes accesses to a specific OSM disk AU@H_301_11@ |
| enq: AD – deallocate AU@H_301_11@ | Synchronizes accesses to a specific OSM disk AU@H_301_11@ |
| enq: AF – task serialization@H_301_11@ | This enqueue is used to serialize access to an advisor task@H_301_11@ |
| enq: AG – contention@H_301_11@ | Synchronizes generation use of a particular workspace@H_301_11@ |
| enq: AO – contention@H_301_11@ | Synchronizes access to objects and scalar variables@H_301_11@ |
| enq: AS – contention@H_301_11@ | Synchronizes new service activation@H_301_11@ |
| enq: AT – contention@H_301_11@ | Serializes ‘alter tablespace’ operations@H_301_11@ |
| enq: AW – AW$ table lock@H_301_11@ | Global access synchronization to the AW$ table@H_301_11@ |
| enq: AW – AW generation lock@H_301_11@ | In-use generation state for a particular workspace@H_301_11@ |
| enq: AW – user access for AW@H_301_11@ | Synchronizes user accesses to a particular workspace@H_301_11@ |
| enq: AW – AW state lock@H_301_11@ | Row lock synchronization for the AW$ table@H_301_11@ |
| enq: BR – file shrink@H_301_11@ | Lock held to prevent file from decreasing in physical size during RMAN backup@H_301_11@ |
| enq: BR – proxy-copy@H_301_11@ | Lock held to allow cleanup from backup mode during an RMAN proxy-copy backup@H_301_11@ |
| enq: CF – contention@H_301_11@ | Synchronizes accesses to the controlfile@H_301_11@ |
| enq: CI – contention@H_301_11@ | Coordinates cross-instance function invocations@H_301_11@ |
| enq: CL – drop label@H_301_11@ | Synchronizes accesses to label cache when dropping a label@H_301_11@ |
| enq: CL – compare labels@H_301_11@ | Synchronizes accesses to label cache for label comparison@H_301_11@ |
| enq: CM – gate@H_301_11@ | Serialize access to instance enqueue@H_301_11@ |
| enq: CM – instance@H_301_11@ | Indicate OSM disk group is mounted@H_301_11@ |
| enq: CT – global space management@H_301_11@ | Lock held during change tracking space management operations that affect the entire change tracking file@H_301_11@ |
| enq: CT – state@H_301_11@ | Lock held while enabling or disabling change tracking,to ensure that it is only enabled or disabled by one user at a time@H_301_11@ |
| enq: CT – state change gate 2@H_301_11@ | Lock held while enabling or disabling change tracking in RAC@H_301_11@ |
| enq: CT – reading@H_301_11@ | Lock held to ensure that change tracking data remains in existence until a reader is done with it@H_301_11@ |
| enq: CT – CTWR process start/stop@H_301_11@ | Lock held to ensure that only one CTWR process is started in a single instance@H_301_11@ |
| enq: CT – state change gate 1@H_301_11@ | Lock held while enabling or disabling change tracking in RAC@H_301_11@ |
| enq: CT – change stream ownership@H_301_11@ | Lock held by one instance while change tracking is enabled,to guarantee access to thread-specific resources@H_301_11@ |
| enq: CT – local space management@H_301_11@ | Lock held during change tracking space management operations that affect just the data for one thread@H_301_11@ |
| enq: CU – contention@H_301_11@ | Recovers cursors in case of death while compiling@H_301_11@ |
| enq: DB – contention@H_301_11@ | Synchronizes modification of database wide supplemental logging attributes@H_301_11@ |
| enq: DD – contention@H_301_11@ | Synchronizes local accesses to ASM disk groups@H_301_11@ |
| enq: DF – contention@H_301_11@ | Enqueue held by foreground or DBWR when a datafile is brought online in RAC@H_301_11@ |
| enq: DG – contention@H_301_11@ | Synchronizes accesses to ASM disk groups@H_301_11@ |
| enq: DL – contention@H_301_11@ | Lock to prevent index DDL during direct load@H_301_11@ |
| enq: DM – contention@H_301_11@ | Enqueue held by foreground or DBWR to synchronize database mount/open with other operations@H_301_11@ |
| enq: DN – contention@H_301_11@ | Serializes group number generations@H_301_11@ |
| enq: DP – contention@H_301_11@ | Synchronizes access to LDAP parameters@H_301_11@ |
| enq: DR – contention@H_301_11@ | Serializes the active distributed recovery operation@H_301_11@ |
| enq: DS – contention@H_301_11@ | Prevents a database suspend during LMON reconfiguration@H_301_11@ |
| enq: DT – contention@H_301_11@ | Serializes changing the default temporary table space and user creation@H_301_11@ |
| enq: DV – contention@H_301_11@ | Synchronizes access to lower-version Diana (PL/sql intermediate representation)@H_301_11@ |
| enq: DX – contention@H_301_11@ | Serializes tightly coupled distributed transaction branches@H_301_11@ |
| enq: FA – access file@H_301_11@ | Synchronizes accesses to open ASM files@H_301_11@ |
| enq: FB – contention@H_301_11@ | Ensures that only one process can format data blocks in auto segment space managed tablespaces@H_301_11@ |
| enq: FC – open an ACD thread@H_301_11@ | LGWR opens an ACD thread@H_301_11@ |
| enq: FC – recover an ACD thread@H_301_11@ | SMON recovers an ACD thread@H_301_11@ |
| enq: FD – Marker generation@H_301_11@ | Synchronization@H_301_11@ |
| enq: FD – Flashback coordinator@H_301_11@ | Synchronization@H_301_11@ |
| enq: FD – Tablespace flashback on/off@H_301_11@ | Synchronization@H_301_11@ |
| enq: FD – Flashback on/off@H_301_11@ | Synchronization@H_301_11@ |
| enq: FG – serialize ACD relocate@H_301_11@ | Only 1 process in the cluster may do ACD relocation in a disk group@H_301_11@ |
| enq: FG – LGWR redo generation enq race@H_301_11@ | Resolve race condition to acquire Disk Group Redo Generation Enqueue@H_301_11@ |
| enq: FG – FG redo generation enq race@H_301_11@ | Resolve race condition to acquire Disk Group Redo Generation Enqueue@H_301_11@ |
| enq: FL – Flashback database log@H_301_11@ | Synchronization@H_301_11@ |
| enq: FL – Flashback db command@H_301_11@ | Enqueue used to synchronize Flashback Database and deletion of flashback logs.@H_301_11@ |
| enq: FM – contention@H_301_11@ | Synchronizes access to global file mapping state@H_301_11@ |
| enq: FR – contention@H_301_11@ | Begin recovery of disk group@H_301_11@ |
| enq: FS – contention@H_301_11@ | Enqueue used to synchronize recovery and file operations or synchronize dictionary check@H_301_11@ |
| enq: FT – allow LGWR writes@H_301_11@ | Allow LGWR to generate redo in this thread@H_301_11@ |
| enq: FT – disable LGWR writes@H_301_11@ | Prevent LGWR from generating redo in this thread@H_301_11@ |
| enq: FU – contention@H_301_11@ | This enqueue is used to serialize the capture of the DB Feature,Usage and High Water Mark Statistics@H_301_11@ |
| enq: HD – contention@H_301_11@ | Serializes accesses to ASM SGA data structures@H_301_11@ |
| enq: HP – contention@H_301_11@ | Synchronizes accesses to queue pages@H_301_11@ |
| enq: HQ – contention@H_301_11@ | Synchronizes the creation of new queue IDs@H_301_11@ |
| enq: HV – contention@H_301_11@ | Lock used to broker the high water mark during parallel inserts@H_301_11@ |
| enq: HW – contention@H_301_11@ | Lock used to broker the high water mark during parallel inserts@H_301_11@ |
| enq: IA – contention@H_301_11@ | |
| enq: ID – contention@H_301_11@ | Lock held to prevent other processes from performing controlfile transaction while NID is running@H_301_11@ |
| enq: IL – contention@H_301_11@ | Synchronizes accesses to internal label data structures@H_301_11@ |
| enq: IM – contention for blr@H_301_11@ | Serializes block recovery for IMU txn@H_301_11@ |
| enq: IR – contention@H_301_11@ | Synchronizes instance recovery@H_301_11@ |
| enq: IR – contention2@H_301_11@ | Synchronizes parallel instance recovery and shutdown immediate@H_301_11@ |
| enq: IS – contention@H_301_11@ | Enqueue used to synchronize instance state changes@H_301_11@ |
| enq: IT – contention@H_301_11@ | Synchronizes accesses to a temp object’s Metadata@H_301_11@ |
| enq: JD – contention@H_301_11@ | Synchronizes dates between job queue coordinator and slave processes@H_301_11@ |
| enq: JI – contention@H_301_11@ | Lock held during materialized view operations (like refresh,alter) to prevent concurrent operations on the same materialized view@H_301_11@ |
| enq: JQ – contention@H_301_11@ | Lock to prevent multiple instances from running a single job@H_301_11@ |
| enq: JS – contention@H_301_11@ | Synchronizes accesses to the job cache@H_301_11@ |
| enq: JS – coord post lock@H_301_11@ | Lock for coordinator posting@H_301_11@ |
| enq: JS – global wdw lock@H_301_11@ | Lock acquired when doing wdw ddl@H_301_11@ |
| enq: JS – job chain evaluate lock@H_301_11@ | Lock when job chain evaluated for steps to create@H_301_11@ |
| enq: JS – q mem clnup lck@H_301_11@ | Lock obtained when cleaning up q memory@H_301_11@ |
| enq: JS – slave enq get lock2@H_301_11@ | Get run info locks before slv objget@H_301_11@ |
| enq: JS – slave enq get lock1@H_301_11@ | Slave locks exec pre to sess strt@H_301_11@ |
| enq: JS – running job cnt lock3@H_301_11@ | Lock to set running job count epost@H_301_11@ |
| enq: JS – running job cnt lock2@H_301_11@ | Lock to set running job count epre@H_301_11@ |
| enq: JS – running job cnt lock@H_301_11@ | Lock to get running job count@H_301_11@ |
| enq: JS – coord rcv lock@H_301_11@ | Lock when coord receives msg@H_301_11@ |
| enq: JS – queue lock@H_301_11@ | Lock on internal scheduler queue@H_301_11@ |
| enq: JS – job run lock – synchronize@H_301_11@ | Lock to prevent job from running elsewhere@H_301_11@ |
| enq: JS – job recov lock@H_301_11@ | Lock to recover jobs running on crashed RAC inst@H_301_11@ |
| enq: KK – context@H_301_11@ | Lock held by open redo thread,used by other instances to force a log switch@H_301_11@ |
| enq: KM – contention@H_301_11@ | Synchronizes varIoUs Resource Manager operations@H_301_11@ |
| enq: KP – contention@H_301_11@ | Synchronizes kupp process startup@H_301_11@ |
| enq: KT – contention@H_301_11@ | Synchronizes accesses to the current Resource Manager plan@H_301_11@ |
| enq: MD – contention@H_301_11@ | Lock held during materialized view log DDL statements@H_301_11@ |
| enq: MH – contention@H_301_11@ | Lock used for recovery when setting Mail Host for AQ e-mail notifications@H_301_11@ |
| enq: ML – contention@H_301_11@ | Lock used for recovery when setting Mail Port for AQ e-mail notifications@H_301_11@ |
| enq: MN – contention@H_301_11@ | Synchronizes updates to the LogMiner dictionary and prevents multiple instances from preparing the same LogMiner session@H_301_11@ |
| enq: MR – contention@H_301_11@ | Lock used to coordinate media recovery with other uses of datafiles@H_301_11@ |
| enq: MS – contention@H_301_11@ | Lock held during materialized view refresh to setup MV log@H_301_11@ |
| enq: MW – contention@H_301_11@ | This enqueue is used to serialize the calibration of the manageability schedules with the Maintenance Window@H_301_11@ |
| enq: OC – contention@H_301_11@ | Synchronizes write accesses to the outline cache@H_301_11@ |
| enq: OL – contention@H_301_11@ | Synchronizes accesses to a particular outline name@H_301_11@ |
| enq: OQ – xsoqhiAlloc@H_301_11@ | Synchronizes access to olapi history allocation@H_301_11@ |
| enq: OQ – xsoqhiClose@H_301_11@ | Synchronizes access to olapi history closing@H_301_11@ |
| enq: OQ – xsoqhistrecb@H_301_11@ | Synchronizes access to olapi history globals@H_301_11@ |
| enq: OQ – xsoqhiFlush@H_301_11@ | Synchronizes access to olapi history flushing@H_301_11@ |
| enq: OQ – xsoq*histrecb@H_301_11@ | Synchronizes access to olapi history parameter CB@H_301_11@ |
| enq: PD – contention@H_301_11@ | Prevents others from updating the same property@H_301_11@ |
| enq: PE – contention@H_301_11@ | Synchronizes system parameter updates@H_301_11@ |
| enq: PF – contention@H_301_11@ | Synchronizes accesses to the password file@H_301_11@ |
| enq: PG – contention@H_301_11@ | Synchronizes global system parameter updates@H_301_11@ |
| enq: PH – contention@H_301_11@ | Lock used for recovery when setting Proxy for AQ HTTP notifications@H_301_11@ |
| enq: PI – contention@H_301_11@ | Communicates remote Parallel Execution Server Process creation status@H_301_11@ |
| enq: PL – contention@H_301_11@ | Coordinates plug-in operation of transportable tablespaces@H_301_11@ |
| enq: PR – contention@H_301_11@ | Synchronizes process startup@H_301_11@ |
| enq: PS – contention@H_301_11@ | Parallel Execution Server Process reservation and synchronization@H_301_11@ |
| enq: PT – contention@H_301_11@ | Synchronizes access to ASM PST Metadata@H_301_11@ |
| enq: PV – syncstart@H_301_11@ | Synchronizes slave start shutdown@H_301_11@ |
| enq: PV – syncshut@H_301_11@ | Synchronizes instance shutdown_slvstart@H_301_11@ |
| enq: PW – perwarm status in dbw0@H_301_11@ | DBWR 0 holds enqueue indicating prewarmed buffers present in cache@H_301_11@ |
| enq: PW – flush prewarm buffers@H_301_11@ | Direct Load needs to flush pre-warmed buffers if DBWR 0 holds enqueue@H_301_11@ |
| enq: RB – contention@H_301_11@ | Serializes OSM rollback recovery operations@H_301_11@ |
| enq: RF – synch: per-SGA Broker Metadata@H_301_11@ | Ensures r/w atomicity of DG configuration Metadata per unique SGA@H_301_11@ |
| enq: RF – synchronization: critical ai@H_301_11@ | Synchronizes critical apply instance among primary instances@H_301_11@ |
| enq: RF – new AI@H_301_11@ | Synchronizes selection of the new apply instance@H_301_11@ |
| enq: RF – synchronization: chief@H_301_11@ | Anoints 1 instance’s DMON as chief to other instances’ DMONs@H_301_11@ |
| enq: RF – synchronization: HC master@H_301_11@ | Anoints 1 instance’s DMON as health check master@H_301_11@ |
| enq: RF – synchronization: aifo master@H_301_11@ | Synchronizes apply instance failure detection and fail over operation@H_301_11@ |
| enq: RF – atomicity@H_301_11@ | Ensures atomicity of log transport setup@H_301_11@ |
| enq: RN – contention@H_301_11@ | Coordinates nab computations of online logs during recovery@H_301_11@ |
| enq: RO – contention@H_301_11@ | Coordinates flushing of multiple objects@H_301_11@ |
| enq: RO – fast object reuse@H_301_11@ | Coordinates fast object reuse@H_301_11@ |
| enq: RP – contention@H_301_11@ | Enqueue held when resilvering is needed or when data block is repaired from mirror@H_301_11@ |
| enq: RS – file delete@H_301_11@ | Lock held to prevent file from accessing during space reclamation@H_301_11@ |
| enq: RS – persist alert level@H_301_11@ | Lock held to make alert level persistent@H_301_11@ |
| enq: RS – write alert level@H_301_11@ | Lock held to write alert level@H_301_11@ |
| enq: RS – read alert level@H_301_11@ | Lock held to read alert level@H_301_11@ |
| enq: RS – prevent aging list update@H_301_11@ | Lock held to prevent aging list update@H_301_11@ |
| enq: RS – record reuse@H_301_11@ | Lock held to prevent file from accessing while reusing circular record@H_301_11@ |
| enq: RS – prevent file delete@H_301_11@ | Lock held to prevent deleting file to reclaim space@H_301_11@ |
| enq: RT – contention@H_301_11@ | Thread locks held by LGWR,DBW0,and RVWR to indicate mounted or open status@H_301_11@ |
| enq: SB – contention@H_301_11@ | Synchronizes Logical Standby Metadata operations@H_301_11@ |
| enq: SF – contention@H_301_11@ | Lock used for recovery when setting Sender for AQ e-mail notifications@H_301_11@ |
| enq: SH – contention@H_301_11@ | Should seldom see this contention as this Enqueue is always acquired in no-wait mode@H_301_11@ |
| enq: SI – contention@H_301_11@ | Prevents multiple streams table instantiations@H_301_11@ |
| enq: SK – contention@H_301_11@ | Serialize shrink of a segment@H_301_11@ |
| enq: SQ – contention@H_301_11@ | Lock to ensure that only one process can replenish the sequence cache@H_301_11@ |
| enq: SR – contention@H_301_11@ | Coordinates replication / streams operations@H_301_11@ |
| enq: SS – contention@H_301_11@ | Ensures that sort segments created during parallel DML operations aren’t prematurely cleaned up@H_301_11@ |
| enq: ST – contention@H_301_11@ | Synchronizes space management activities in dictionary-managed tablespaces@H_301_11@ |
| enq: SU – contention@H_301_11@ | Serializes access to SaveUndo Segment@H_301_11@ |
| enq: SW – contention@H_301_11@ | Coordinates the ‘alter system suspend’ operation@H_301_11@ |
| enq: TA – contention@H_301_11@ | Serializes operations on undo segments and undo tablespaces@H_301_11@ |
| enq: TB – sql Tuning Base Cache Update@H_301_11@ | Synchronizes writes to the sql Tuning Base Existence Cache@H_301_11@ |
| enq: TB – sql Tuning Base Cache Load@H_301_11@ | Synchronizes writes to the sql Tuning Base Existence Cache@H_301_11@ |
| enq: TC – contention@H_301_11@ | Lock held to guarantee uniqueness of a tablespace checkpoint@H_301_11@ |
| enq: TC – contention2@H_301_11@ | Lock of setup of a unique tablespace checkpoint in null mode@H_301_11@ |
| enq: TD – KTF dump entries@H_301_11@ | KTF dumping time/scn mappings in SMON_SCN_TIME table@H_301_11@ |
| enq: TE – KTF broadcast@H_301_11@ | KTF broadcasting@H_301_11@ |
| enq: TF – contention@H_301_11@ | Serializes dropping of a temporary file@H_301_11@ |
| enq: TL – contention@H_301_11@ | Serializes threshold log table read and update@H_301_11@ |
| enq: TM – contention@H_301_11@ | Synchronizes accesses to an object@H_301_11@ |
| enq: TO – contention@H_301_11@ | Synchronizes DDL and DML operations on a temp object@H_301_11@ |
| enq: TQ – TM contention@H_301_11@ | TM access to the queue table@H_301_11@ |
| enq: TQ – DDL contention@H_301_11@ | TM access to the queue table@H_301_11@ |
| enq: TQ – INI contention@H_301_11@ | TM access to the queue table@H_301_11@ |
| enq: TS – contention@H_301_11@ | Serializes accesses to temp segments@H_301_11@ |
| enq: TT – contention@H_301_11@ | Serializes DDL operations on tablespaces@H_301_11@ |
| enq: TW – contention@H_301_11@ | Lock held by one instance to wait for transactions on all instances to finish@H_301_11@ |
| enq: TX – contention@H_301_11@ | Lock held by a transaction to allow other transactions to wait for it@H_301_11@ |
| enq: TX – row lock contention@H_301_11@ | Lock held on a particular row by a transaction to prevent other transactions from modifying it@H_301_11@ |
| enq: TX – allocate ITL entry@H_301_11@ | Allocating an ITL entry in order to begin a transaction@H_301_11@ |
| enq: TX – index contention@H_301_11@ | Lock held on an index during a split to prevent other operations on it@H_301_11@ |
| enq: UL – contention@H_301_11@ | Lock used by user applications@H_301_11@ |
| enq: US – contention@H_301_11@ | Lock held to perform DDL on the undo segment@H_301_11@ |
| enq: WA – contention@H_301_11@ | Lock used for recovery when setting Watermark for memory usage in AQ notifications@H_301_11@ |
| enq: WF – contention@H_301_11@ | This enqueue is used to serialize the flushing of snapshots@H_301_11@ |
| enq: WL – contention@H_301_11@ | Coordinates access to redo log files and archive logs@H_301_11@ |
| enq: WP – contention@H_301_11@ | This enqueue handles concurrency between purging and baselines@H_301_11@ |
| enq: XH – contention@H_301_11@ | Lock used for recovery when setting No Proxy Domains for AQ HTTP notifications@H_301_11@ |
| enq: XR – quiesce database@H_301_11@ | Lock held during database quiesce@H_301_11@ |
| enq: XR – database force logging@H_301_11@ | Lock held during database force logging mode@H_301_11@ |
| enq: XY – contention@H_301_11@ | Lock used for internal testing@H_301_11@ |
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