BEGIN_TIME |
DATE |
Identifies the beginning of the time interval. |
END_TIME |
DATE |
Identifies the end of the time interval. |
UNDOTSN |
NUMBER |
Represents the last active undo tablespace in the duration of time. The tablespace ID of the active undo tablespace is returned in this column. If more than one undo tablespace was active in that period, the active undo tablespace that was active at the end of the period is reported. |
UNDOBLKS |
NUMBER |
Represents the total number of undo blocks consumed. You can use this column to obtain the consumption rate of undo blocks, and thereby estimate the size of the undo tablespace needed to handle the workload on your system. |
TXNCOUNT |
NUMBER |
Identifies the total number of transactions executed within the period. |
MAXQUERYLEN |
NUMBER |
Identifies the length of the longest query (in number of seconds) executed in the instance during the period. You can use this statistic to estimate the proper setting of the UNDO_RETENTION parameter. |
MAXCONCURRENCY |
NUMBER |
Identifies the highest number of transactions executed concurrently within the period. |
UNXPSTEALCNT |
NUMBER |
The number of attempts to obtain undo space by stealing unexpired extents from other transactions. |
UNXPBLKRELCNY |
NUMBER |
The number of unexpired blocks removed from certain undo segments so they can be used by other transactions. |
UNXPBLKREUCNT |
NUMBER |
The number of unexpired undo blocks reused by transactions. |
EXPSTEALCNT |
NUMBER |
The number of attempts to steal expired undo blocks from other undo segments. |
EXPBLKRELCNT |
NUMBER |
The number of expired undo blocks stolen from other undo segments. |
EXPBLKREUCNT |
NUMBER |
The number of expired undo blocks reused within the same undo segments. |
SSOLDERRCNT |
NUMBER |
Identifies the number of OER errors occurring within a period. You can use this statistic to decide whether or not the UNDO_RETENTION parameter is set properly given the size of the undo tablespace. Lowering the UNDO_RETENTION value can reduce the occurrence of this error. |
NOSPACEERRCNT |
NUMBER |
Identifies the number of OER errors reported in the current instance. If there is a nonzero value in this column, the current undo tablespace needs more space (in the UNDO_RETENTION parameter). |