Wait Event

Performance views which is related to the wait event is as follows.

• v$system_event V$SYSTEM_EVENT

• v$session_event V$SESSION_EVENT

• v$session_wait V$SESSION_WAIT

• v$wait_event_name V$WAIT_EVENT_NAME

• v$wait_event_class_name V$WAIT_EVENT_CLASS_NAME

Class of Wait Event

• Administrative: Waits resulting from DBA commands that cause users to wait (for example, an index rebuild)

• Application: Waits resulting from user application code (for example, lock waits caused by row level locking or explicit lock commands)

• Cluster: Waits related to cluster resources (for example, global cache resources )

• Commit: This wait class only comprises one wait event - wait for redo log write confirmation after a commit (that is, 'log file sync')

• Concurrency: Waits for internal database resources (for example, latches)

• Configuration: Waits caused by inadequate configuration of database or instance resources (for example, undersized log file sizes, shared pool size)

• Idle: Waits that signify the session is inactive, waiting for work (for example, 'gsql message from client')

• Network: Waits related to network messaging

• Other: Waits which should not typically occur on a system

• Scheduler: Resource manager related waits

• System IO: Waits for background process IO

• User IO: Waits for user IO

Item of Wait Event

ENQUEUE: GDISPATCHER REQUEST

It is the time of which GDISPATCHER enqueues a request in a shared mode.
Parameter: None

ENQUEUE: SHARED-SERVER RESPONSE

It is the time of which a shared server enqueues a response in a shared mode.
Parameter: None

DEQUEUE: SHARED-SERVER REQUEST

It is the time of which a shared server dequeues a request in a shared mode.
Parameter: None

DEQUEUE: GDISPATCHER RESPONSE

It is the time of which GDISPATCHER dequeues a response in a shared mode.
Parameter: None

SEND: DEDICATE-SERVER SPOOLED RESPONSE

It is the time of which a dedicate server sends the spooled response to the client in a dedicate mode.

SEND: DEDICATE-SERVER RESPONSE

It is the time of which a dedicate server sends a response to the client in a dedicate mode.

RECV: DEDICATE-SERVER REQUEST

It is the time of which a dedicate server receives a request from the client in a dedicate mode.
Parameter: None

SEND: GDISPATCHER RESPONSE

It is the time of which GDISPATCHER sends a response to a client in a shared mode.

RECV: GDISPATCHER REQUEST

It is the time of which GDISPATCHER receives a request from a client in a shared mode.
Parameter: None

ENQUEUE: CLUSTER REQUEST

It is the time of enqueuing a request of cluster.
Parameter: None

ENQUEUE: CLUSTER BROADCAST REQUEST

It is the time of enqueuing a broadcast request of cluster.
Parameter: None

DEQUEUE: CLUSTER RESPONSE

It is the time of dequeuing a response of cluster.
Parameter: None

SEND: CDISPATCHER

It is the time of sending in cluster CDISPATCHER.
Parameter: None

RECV: CDISPATCHER

It is the time of receiving in cluster CDISPATCHER.
Parameter: None

GMASTER: ARCHIVE LOG

It is the time of processing archive logs in gmaster.
Parameter: None

GMASTER: CHECKPOINT

It is the time of processing checkpoints in gmaster.
Parameter: None

GMASTER: IO SLAVE

It is the time of processing IO slave in gmaster.
Parameter: None

GMASTER: LOG FLUSH

It is the time of processing archive logs in gmaster.
Parameter: None

GMASTER: PAGE FLUSH

It is the time of processing page flush in gmaster.
Parameter: None

WRITE: TRACE LOG

It is the time of writing trace logs.
Parameter: None

WRITE: COPY ARCHIVING LOG

It is the time of copying archiving logs.
Parameter: None

WRITE: BACKUP CTRL FILE

It is the time of backing up control files.
Parameter: None

WRITE: RESTORE CTRL FILE

It is the time of restoring the control file.
Parameter: None

READ: ARCHIVE LOG

It is the time of reading archive log files.
Parameter: None

READ: CTRL FILE

It is the time of reading the control file.
Parameter: None

WRITE: LOG FILE

It is the time of writing log files.
Parameter: None

WRITE: PAGE FILE

It is the time of writing page files.
Parameter: None

WRITE: CTRL FILE

It is the time of writing the control file.
Parameter: None

WRITE: REMOVE DATA FILE

It is the time of removing the data file.
Parameter: None

WRITE: JOURNAL BUFFER

It is the time of writing journal buffers.
Parameter: None

READ: JOURNAL BUFFER

It is the time of reading journal buffers.
Parameter: None

WAIT TRANSACTION

It is the time of waiting for transactions.

WAIT OTHER TRANSACTION

It is the time of waiting for other transactions to be terminated.

WAIT ENABLE LOGGING

It is the time of waiting until when the logging is available.
Parameter: None

WAIT LOG FLUSHER

It is the time of waiting for the log flusher.

WAIT PAGE FLUSHER

It is the time of waiting for the page flusher.

WAIT XA CONTEXT

It is the time of waiting for the XA context.
Parameter: None

LATCH: LOG BUFFER

It is the time of waiting for the log buffer latch.

LATCH: PROCESS MANAGER

It is the time of waiting for the process manager latch.

LATCH: ENV MGR

It is the time of waiting for the env manager latch.

LATCH: SESSION ENV MGR

It is the time of waiting for the session env manager latch.

LATCH: PCH

It is the time of waiting for the Page Control Header (PCH) latch.

LATCH: PAGE

It is the time of waiting for the page latch.

LATCH: PENDING LOG

It is the time of waiting for the pending log latch.

LATCH: ALLOC TRANS

It is the time of waiting for the allocate transaction latch.

LATCH: UNDO SEGMENT

It is the time of waiting for the undo segment latch.

LATCH: CLUSTER LOCATION

It is the time of waiting for the cluster location latch.

LATCH: DICT HASH ELEMENT AGING

It is the time of waiting for the dict hash element aging latch.

LATCH: DICT HASH RELATED AGING

It is the time of waiting for the dict hash related aging latch.

LATCH: FILE MANAGER

It is the time of waiting for the file manager latch.

LATCH: TRACE LOG

It is the time of waiting for the trace log latch.

LATCH: STATIC HASH

It is the time of waiting for the static hash latch.

LATCH: STATIC HASH BUCKET

It is the time of waiting for the static hash bucket latch.

LATCH: SQL HANDLE

It is the time of waiting for SQL handle latch.

LATCH: XA CONTEXT HASH

It is the time of waiting for XA context hash latch.

LATCH: PLAN CLOCK

It is the time of waiting for the plan clock latch.

LATCH: XA CONTEXT

It is the time of waiting for XA context latch.

LATCH: MEM CONTROLLER

It is the time of waiting for the memory controller latch.

LATCH: DYNAMIC MEM

It is the time of waiting for the dynamic memory latch.

LATCH: PROPERTY

It is the time of waiting for the property latch.

LATCH: ATTACH SHM

It is the time of waiting for the attack shared memory latch.

LATCH: BACKUP TBS

It is the time of waiting for the backup tablespace latch.

LATCH: DATABASE COMPONENT

It is the time of waiting for the database component latch.

LATCH: TABLESPACE

It is the time of waiting for the tablespace latch.

LATCH: BACKUP DATABASE

It is the time of waiting for the backup database latch.

LATCH: JOURNAL BUFFER

It is the time of waiting for the journal buffer latch.

LATCH: JOURNAL BUFFER ENTRY

It is the time of waiting for the journal buffer entry latch.

LATCH: JOURNAL WRITE BUFFER

It is the time of waiting for the journal write buffer latch.

LATCH: LOCK ITEM

It is the time of waiting for the lock item latch.

LATCH: RECORD HASH

It is the time of waiting for the record hash latch.

LATCH: DEADLOCK

It is the time of waiting for the deadlock latch.

LATCH: SEQUENCE

It is the time of waiting for the sequence latch.

LATCH: LOG STREAM

It is the time of waiting for the log stream latch.

LATCH: BUILD AGABLE SCN

It is the time of waiting for the build agable SCN latch.

LATCH: TRANSACTION TABLE

It is the time of waiting for the transaction table latch.

LATCH: SESSION LINK HASH

It is the time of waiting for the session link hash latch.

LATCH: ALLOC XA CONTEXT

It is the time of waiting for the allocate XA context latch.

LATCH: SEQUENCE GLOBALX

It is the time of waiting for the sequence global latch X.

LATCH: SEQUENCE GLOBALY

It is the time of waiting for the sequence global latch Y.

LATCH: TRANSACTION LOG FILE

It is the time of waiting for the transaction logfile latch.

ASYNC RESPONSE

It is the time of waiting for the response from the remote node in the cluster environment.
Parameter: None

ASYNC TRANSACTION

It is the time of waiting for the response for the ASYNC TRANSACTION's COMMIT from the remote node in the cluster environment.
Parameter: None

ASYNC COMMIT

N/A

GMASTER: BUFFER FLUSH

It is the time of executing the buffer flush by the io slave of gmaster.
Parameter: None

LATCH: BUFFER HASH BUCKET

It is the time of waiting for the buffer hash bucket's latch.

READ: PAGE FILE

It is the time of reading pages from the disk to read the disk tablespace's pages.
Parameter: None

LATCH: BUFFER CHECKPOINT LIST

N/A

WRITE: CHANGE TRACKING FILE

It is the time of writing the disk tablespace's change tracking file.
Parameter: None

WAIT FREE BUFFER

It is the time of waiting for the free buffer, to read the pages in the disk tablespace.
Parameter: None

GLOBAL SEQUENCE: LOCK AND QUERY

It is the time of waiting for the global latch by all members to synchronize the global sequence in cluster, and the time of waiting to get the latest information of the global sequence.
Parameter: None

GLOBAL SEQUENCE: SYNC

It is the time of synchronizing the global sequence in cluster.
Parameter: None

LATCH: SEQUENCE GLOBAL NEXT

It is the time of waiting for the sequence global next latch in cluster.

LATCH: BUFFER LRU LIST

It is the time of waiting for the buffer lru list latch.

WAIT DIRTY PAGE LIMIT

It is the time of waiting until the number of dirty pages in the system becomes smaller than BUFFER_DIRTY_PAGE_LIMIT to access the pages cached in the buffer. 
Parameter: None

WAIT BUFFER READ COMPLETE

It is the time of waiting for the disk read to be completed to access the page of the disk tablespace.
Parameter: None