Rollback Segment (PD_PDRS)
- Organization of this page
Function
The Rollback Segment (PD_PDRS) record stores performance data indicating the status of each rollback segment in a database at a specific point in time. PFM - Agent for Oracle creates one record for each rollback segment. This is a multi-instance record.
Default and changeable values
|
Item |
Default value |
Changeable |
|---|---|---|
|
Collection Interval |
300 |
Y |
|
Collection Offset |
30 |
Y |
|
Log |
No |
Y |
|
LOGIF |
(Blank) |
Y |
|
Over 10 Sec Collection Time |
No |
N |
ODBC key fields
PD_PDRS_USN
Lifetime
From the creation to the deletion of a rollback segment
Record size
-
Fixed part: 678 bytes
-
Variable part: 190 bytes
Fields
|
PFM - View name (PFM - Manager name) |
Description |
Summary |
Format |
Delta |
Supported version |
Data source |
|---|---|---|---|---|---|---|
|
Avg Active (AVG_ACTIVE) |
Average size of an active extent that has uncommitted transaction data during data collection |
-- |
double |
No |
All |
V$ROLLSTAT.AVEACTIVE |
|
Avg Shrink (AVG_SHRINK) |
Total size of released extents divided by the number of shrinks Extends |
-- |
double |
No |
All |
V$ROLLSTAT.AVESHRINK |
|
Extends (EXTENDS) |
Number of times the rollback segment was extended to obtain new extents |
-- |
double |
No |
All |
V$ROLLSTAT.EXTENDS |
|
Extents (EXTENTS) |
Number of extents in the rollback segment |
-- |
ulong |
No |
All |
V$ROLLSTAT.EXTENTS |
|
Gets (GETS) |
Number of times header was obtained |
-- |
double |
No |
All |
V$ROLLSTAT.GETS |
|
HWM Size (HWM_SIZE) |
Maximum size of rollback segment |
-- |
double |
No |
All |
V$ROLLSTAT.HWMSIZE |
|
Hit % (HIT_PERCENTAGE) |
Percentage of times that a segment header was obtained without waiting |
-- |
double |
No |
All |
((V$ROLLSTAT.GETS - V$ROLLSTAT.WAITS) / V$ROLLSTAT.GETS) * 100 |
|
Mbytes (BYTES) |
Size of rollback segment in megabytes |
-- |
double |
No |
All |
V$ROLLSTAT.RSSIZE / (1024 * 1024) |
|
Optimal Size (OPT_SIZE) |
Optimum size of rollback segment |
-- |
double |
No |
All |
V$ROLLSTAT.OPTSIZE |
|
Record Time (RECORD_TIME) |
Collection termination time for the performance data stored in the record |
-- |
time_t |
No |
All |
Agent Collector |
|
Record Type (INPUT_RECORD_TYPE) |
Record name (always PDRS) |
-- |
string(4) |
No |
All |
Agent Collector |
|
Segment Name (NAME) |
Name of the rollback segment |
-- |
string(30) |
No |
All |
V$ROLLNAME.NAME |
|
Shrinks (SHRINKS) |
Number of times the rollback segment shrank by deleting at least one additional extent |
-- |
double |
No |
All |
V$ROLLSTAT.SHRINKS |
|
Start Time (START_TIME) |
Collection start time for the performance data stored in the record |
-- |
time_t |
No |
All |
Agent Collector |
|
Status (STATUS) |
Status. Valid values are ONLINE (segment is online) and PENDINGOFFLINE (segment is offline, but several active transactions are used in the rollback segment; segment is placed offline when transactions are completed). |
-- |
string(15) |
No |
All |
V$ROLLSTAT.STATUS |
|
Tablespace Name (TABLESPACE_NAME) |
Name of tablespace that contains the segment |
-- |
string(30) |
No |
All |
DBA_ROLLBACK_SEGS.TABLESPACE_NAME |
|
Transactions (TRANSACTIONS) |
Number of active transactions |
-- |
long |
No |
All |
V$ROLLSTAT.XACTS |
|
USN (USN) |
Rollback segment number |
-- |
double |
No |
All |
V$ROLLSTAT.USN |
|
Waits (WAITS) |
Number of header waits |
-- |
double |
No |
All |
V$ROLLSTAT.WAITS |
|
Wraps (WRAPS) |
Number of times rollback segment was wrapped from one extent to another |
-- |
double |
No |
All |
V$ROLLSTAT.WRAPS |
|
Writes (WRITES) |
Number of bytes written in the rollback segment |
-- |
double |
No |
All |
V$ROLLSTAT.WRITES |