Today I will be sharing the member wait events present in wait event classes. By looking into the list one can conclude to which parent class the occurring events belong to and narrow down the investigation.
Oracle Wait Events are conditions where a session is waiting for something to happen. A wait event can be caused by many things, from slow read/write speeds on the disk, to locking situations caused by the architecture, to various kinds of Oracle contentions. Waits are either system-level or session-level. A session-level wait event is an event that affects a single user activity within the database. System-level wait events affect the entire database system.
Administrative
JS kill job wait
JS coord start wait
Backup: sbtinit
Backup: sbtopen
Backup: sbtread
Backup: sbtwrite
Backup: sbtclose
Backup: sbtinfo
Backup: sbtremove
Backup: sbtbackup
Backup: sbtclose2
Backup: sbtcommand
Backup: sbtend
Backup: sbterror
Backup: sbtinfo2
Backup: sbtinit2
Backup: sbtread2
Backup: sbtremove2
Backup: sbtrestore
Backup: sbtwrite2
Backup: sbtpcbackup
Backup: sbtpccancel
Backup: sbtpccommit
Backup: sbtpcend
Backup: sbtpcquerybackup
Backup: sbtpcqueryrestore
Backup: sbtpcrestore
Backup: sbtpcstart
Backup: sbtpcstatus
Backup: sbtpcvalidate
Backup: sbtgetbuf
Backup: sbtrelbuf
Backup: sbtmapbuf
Backup: sbtbufinfo
multiple dbwriter suspend/resume for file offline
buffer pool resize
switch logfile command
wait for possible quiesce finish
switch undo – offline
alter rbs offline
enq: TW – contention
index (re)build online start
index (re)build online cleanup
index (re)build online merge
alter system set dispatcher
connection pool wait
enq: DB – contention
enq: ZG – contention
ASM COD rollback operation completion
ASM mount : wait for heartbeat
JS kgl get object wait
Application
enq: PW – flush prewarm buffers
WCR: replay lock order
enq: RO – fast object reuse
enq: KO – fast object checkpoint
enq: TM – contention
enq: TX – row lock contention
Wait for Table Lock
enq: RC – Result Cache: Contention
Streams capture: filter callback waiting for ruleset
Streams: apply reader waiting for DDL to apply
SQLNet break/reset to client SQLNet break/reset to dblink
enq: UL – contention
OLAP DML Sleep
enq: RO – contention
Cluster
ASM PST query : wait for [PM][grp][0] grant
gc claim
retry contact SCN lock master
gc buffer busy acquire
gc buffer busy release
pi renounce write complete
gc current request
gc cr request
gc cr disk request
gc cr multi block request
gc current multi block request
gc block recovery request
gc cr block 2-way
gc cr block 3-way
gc cr block busy
gc cr block congested
gc cr failure
gc cr block lost
gc cr block unknown
gc current block 2-way
gc current block 3-way
gc current block busy
gc current block congested
gc current retry
gc current block lost
gc current split
gc current block unknown
gc cr grant 2-way
gc cr grant busy
gc cr grant congested
gc cr grant unknown
gc cr disk read
gc current grant 2-way
gc current grant busy
gc current grant congested
gc current grant unknown
gc freelist
gc remaster
gc quiesce
gc object scan
gc current cancel
gc cr cancel
gc assume
gc domain validation
gc recovery free
gc recovery quiesce
Lock remastering
Commit
log file sync
Enq: BB – 2PC across RAC instances
Concurrency
latch: MQL Tracking Latch
enq: WG – lock fso
latch: row cache objects
row cache lock
row cache read
cursor: mutex X
cursor: mutex S
cursor: pin S wait on X
latch: shared pool
library cache pin
library cache lock
library cache load lock
library cache: mutex X
library cache: mutex S
resmgr:internal state change
resmgr:internal state cleanup
resmgr:sessions to exit
pipe put
logout restrictor
os thread startup
Shared IO Pool Memory
latch: cache buffers chains
buffer busy waits
latch: In memory undo latch
enq: TX – index contention
latch: Undo Hint Latch
Configuration
enq: TX – allocate ITL entry
statement suspended, wait error to be cleared
enq: HW – contention
enq: SS – contention
sort segment request
enq: SQ – contention
Global transaction acquire instance locks
wait for EMON to process ntfns
free buffer waits
checkpoint completed
write complete waits
latch: redo writing
latch: redo copy
log buffer space
log file switch (checkpoint incomplete)
log file switch (private strand flush incomplete)
log file switch (archiving needed)
log file switch completion
enq: ST – contention
undo segment extension
undo segment tx slot
Network
remote db operation
TEXT: URL_DATASTORE network wait
remote db file write
ARCH wait for netserver start
ARCH wait for netserver init 1
ARCH wait for netserver init 2
ARCH wait for flow-control
ARCH wait for netserver detach
ARCH wait for net re-connect
LNS wait on ATTACH
LNS wait on SENDREQ
LNS wait on DETACH
LNS wait on LGWR
LGWR wait on ATTACH
LGWR wait on SENDREQ
LGWR wait on DETACH
LGWR wait on LNS
ARCH wait on ATTACH
ARCH wait on SENDREQ
ARCH wait on DETACH
TCP Socket (KGAS)
dispatcher listen timer
dedicated server timer
SQLNet message to client SQLNet message to dblink
SQLNet more data to client SQLNet more data to dblink
SQLNet more data from client SQLNet message from dblink
SQLNet more data from dblink SQLNet vector data to client
SQLNet vector data from client SQLNet vector data to dblink
SQL*Net vector data from dblink
remote db file read
Queueing
Streams capture: resolve low memory condition
Streams AQ: enqueue blocked on low memory
APPENDIX C: A COMPLETE LIST OF ALL WAIT EVENTS IN ORACLE 11g 653
Streams AQ: enqueue blocked due to flow control
Streams capture: waiting for subscribers to catch up
Scheduler
resmgr:cpu quantum
resmgr:I/O prioritization
resmgr:become active
System I/O
control file single write
control file parallel write
control file sequential read
io done
Network file transfer
Standby redo I/O
RMAN backup & recovery I/O
Log archive I/O
ksfd: async disk IO
ARCH sequential i/o
db file parallel write
log file parallel write
log file single write
log file sequential read
ARCH random i/o
kfk: async disk IO
RFS write
RFS random i/o
RFS sequential i/o
LGWR random i/o
LGWR sequential i/o
LNS ASYNC control file txn
recovery read
User I/O
db file sequential read
buffer read retry
db file single write
Datapump dump file I/O
db file parallel read
direct path read
direct path read temp
direct path write
dbms_file_transfer I/O
DG Broker configuration file I/O
Data file init write
dbverify reads
Log file init write
Shared IO Pool IO Completion
local write wait
BFILE read
securefile direct-write completion
securefile direct-read completion
Intelligent Storage OSS I/O completion
direct path write temp
read by other session
db file scattered read
I am a DBA 