Database Reference
In-Depth Information
db file scattered read file# block# blocks
db file sequential read file# block# blocks
direct path read file number first dba block cnt
direct path write file number first dba block cnt
enq: MR - contention name|mode 0 or file # type
enq: ST - contention name|mode 0 0
enq: TM - contention name|mode object # table/partition
enq: TX - allocate ITL entry name|mode usn<<16 | slot sequence
enq: TX - contention name|mode usn<<16 | slot sequence
enq: TX - index contention name|mode usn<<16 | slot sequence
enq: TX - row lock contention name|mode usn<<16 | slot sequence
enq: UL - contention name|mode id 0
enq: US - contention name|mode undo segment # 0
latch free address number tries
latch: gcs resource hash address number tries
latch: ges resource hash list address number tries
latch: library cache address number tries
latch: library cache lock address number tries
latch: library cache pin address number tries
latch: redo allocation address number tries
latch: redo copy address number tries
latch: shared pool address number tries
Parameters of
WAIT
entries relate to data dictionary or V$ views. For example, the parame-
ters “file#” and “file number” both correspond to
V$DATAFILE.FILE#
, the parameter “object#”
refers to
DBA_OBJECTS.OBJECT_ID
, and the parameter “address” of latch waits corresponds to
V$LATCH.ADDRESS
. Since latch and enqueue wait event names are more specific in Oracle10
g
,
the need to drill down to the referenced enqueue or latch through the parameters of a wait
event has been greatly reduced compared to Oracle9
i
.
WAIT in Oracle9
i
WAIT
entry parameters in Oracle9
i
are called
p1
,
p2
, and
p3
generically. The meanings of the param-
eters are not evident from their names as in Oracle10
g
. Instead, the meanings of the parameters
must be derived from the wait event name using the documentation or
V$EVENT_NAME
. The
parameters of Oracle9
i
WAIT
entries are provided in Table 24-10.
Table 24-10.
Oracle9i WAIT Parameters
Parameter
Meaning
ela
Elapsed time in microseconds (centiseconds in de-supported releases such as
Oracle8
i
and earlier).
p1
First parameter of the wait event. The meaning of the parameter is to be found
in
V$EVENT_NAME.PARAMETER1
. The value corresponds to
V$SESSION_WAIT.P1
.
p2
Second parameter of the wait event, analogous to
p1
, i.e., look at
V$EVENT_NAME.
PARAMETER2
for the meaning of the parameter.
p3
Third parameter of the wait event, analogous to
p1
.
