Latch (PD_PDLA)
- Organization of this page
Function
The Latch (PD_PDLA) record stores performance data indicating the status of latches at a specific point in time. PFM - Agent for Oracle creates one record for each latch in an instance. This is a multi-instance record.
- Notes
-
If the monitoring target is Oracle Database 12c Release 2 or later in a CDB configuration, this record includes latch information of monitoring PDB and common latch information for database instances.
Default and changeable values
|
Item |
Default value |
Changeable |
|---|---|---|
|
Collection Interval |
300 |
Y |
|
Collection Offset |
10 |
Y |
|
Log |
No |
Y |
|
LOGIF |
(Blank) |
Y |
|
Over 10 Sec Collection Time |
No |
N |
ODBC key fields
-
PD_PDLA_LATCH_NUM
-
PD_PDLA_LEVEL_NUM
Lifetime
From the creation to the deletion of an Oracle instance
Record size
-
Fixed part: 678 bytes
-
Variable part: 284 bytes
Fields
|
PFM - View name (PFM - Manager name) |
Description |
Summary |
Format |
Delta |
Supported version |
Data source |
|---|---|---|---|---|---|---|
|
Addr (ADDR) |
Latch address |
-- |
string(16) |
No |
All |
V$LATCH.ADDR |
|
Gets (GETS) |
Number of times latches were obtained for requests in the willingto-wait mode |
-- |
double |
No |
All |
V$LATCH.GETS |
|
Immediate Gets (IMMEDIATE_GETS) |
Number of times latches were obtained for requests in the no wait mode |
-- |
double |
No |
All |
V$LATCH.IMMEDIATE_GETS |
|
Immediate Hit % (IMMEDIATE_HIT_PERCENTAGE) |
Percentage of times that latches were obtained in the no wait mode (Rate at which latches were obtained in the first attempt) |
-- |
double |
No |
All |
(V$LATCH.IMMEDIATE_GETS/(V$LATCH.IMMEDIATE_GETS + V$LATCH.IMMEDIATE_MISSES))* 100 |
|
Immediate Misses (IMMEDIATE_MISSES) |
Number of times latch acquisition failed for requests in the no wait mode |
-- |
double |
No |
All |
V$LATCH.IMMEDIATE_MISSES |
|
Latch # (LATCH_NUM) |
Latch number |
-- |
short |
No |
All |
V$LATCH.LATCH# |
|
Latch Name (NAME) |
Latch name |
-- |
string(50) |
No |
All |
V$LATCHNAME.NAME |
|
Level # (LEVEL_NUM) |
Latch level |
-- |
double |
No |
All |
V$LATCH.LEVEL# |
|
Misses (MISSES) |
Number of times the first attempt at latch acquisition failed for requests in the willingto-wait mode |
-- |
double |
No |
All |
V$LATCH.MISSES |
|
OS PID (OS_PID) |
OS's client process ID |
-- |
string(12) |
No |
All |
V$SESSION.PROCESS where V$LATCHHOLDER.SID = V$SESSION.SID |
|
OS User (OS_USER) |
OS's client user name |
-- |
string(30) |
No |
All |
V$SESSION.OSUSER where V$LATCHHOLDER.SID = V$SESSION.SID |
|
Oracle PID (PID) |
Process ID to which the latch belongs |
-- |
ulong |
No |
All |
V$LATCHHOLDER.PID |
|
Program (PROGRAM) |
Name of the program being executed |
-- |
string(48) |
No |
All |
V$SESSION.PROGRAM where V$LATCHHOLDER.SID = V$SESSION.SID |
|
Record Time (RECORD_TIME) |
Collection termination time for the performance data stored in the record |
-- |
time_t |
No |
All |
Agent Collector |
|
Record Type (INPUT_RECORD_TYPE) |
Record name (always PDLA) |
-- |
string(4) |
No |
All |
Agent Collector |
|
SID (SID) |
Session ID to which the latch belongs |
-- |
ulong |
No |
All |
V$LATCHHOLDER.SID |
|
Sleeps (SLEEPS) |
Number of times the system slept when it needed to wait |
-- |
double |
No |
All |
V$LATCH.SLEEPS |
|
Spin Gets (SPIN_GETS) |
Number of latch requests that can wait that failed the first time but were successful during spinning |
-- |
double |
No |
All |
V$LATCH.SPIN_GETS |
|
Start Time (START_TIME) |
Collection start time for the performance data stored in the record |
-- |
time_t |
No |
All |
Agent Collector |
|
User (USERNAME) |
Oracle user name |
-- |
string(30) |
No |
All |
V$SESSION.USERNAME |
|
Waiters Woken (WAITERS_WOKEN) |
Number of times standby sleep was released (always 0 for Oracle 10g Release 2 or later) |
-- |
double |
No |
All |
V$LATCH.WAITERS_WOKEN |
|
Waits Holding Latch (WAITS_HOLDING_LATCH) |
Number of waits when other latches were held (always 0 for Oracle 10g Release 2 or later) |
-- |
double |
No |
All |
V$LATCH.WAITS_HOLDING_LATCH |
|
Willing To Wait Hit % (WILLING_TO_WAIT_HIT_PERCENTAGE) |
Percentage of times that latches were obtained in the willingto-wait mode (Rate at which latches were obtained in the first attempt) |
-- |
double |
No |
All |
((V$LATCH.GETS - V$LATCH.MISSES) / V$LATCH.GETS) * 100 |