SNAP_ID |
NUMBER |
NOT NULL |
Unique snapshot ID |
DBID |
NUMBER |
NOT NULL |
Database ID for the snapshot |
INSTANCE_NUMBER |
NUMBER |
NOT NULL |
Instance number for the snapshot |
PGA_TARGET_FOR_ESTIMATE |
NUMBER |
NOT NULL |
Value of PGA_AGGREGATE_TARGET for the prediction (in bytes) |
PGA_TARGET_FACTOR |
NUMBER |
|
PGA_TARGET_FOR_ESTIMATE / the current value of the PGA_AGGREGATE_TARGET parameter |
ADVICE_STATUS |
VARCHAR2(3) |
|
Indicates whether the advice is enabled (ON) or disabled (OFF) depending on the value of the STATISTICS_LEVEL parameter |
BYTES_PROCESSED |
NUMBER |
|
Total bytes processed by all the work areas considered by this advice (in bytes) |
ESTD_TIME |
NUMBER |
|
Time (in seconds) required to process the bytes |
ESTD_EXTRA_BYTES_RW |
NUMBER |
|
Estimated number of extra bytes which would be read or written if PGA_AGGREGATE_TARGET was set to the value of the PGA_TARGET_FOR_ESTIMATE column. This number is derived from the estimated number and size of work areas which would run in one-pass (or multi-pass) for that value of PGA_AGGREGATE_TARGET. |
ESTD_PGA_CACHE_HIT_PERCENTAGE |
NUMBER |
|
Estimated value of the cache hit percentage statistic when PGA_AGGREGATE_TARGET equals PGA_TARGET_FOR_ESTIMATE. This column is derived from the above two columns and is equal to BYTES_PROCESSED / (BYTES_PROCESSED + ESTD_EXTRA_BYTES_RW) |
ESTD_OVERALLOC_COUNT |
NUMBER |
|
Estimated number of PGA memory over-allocations if the value of PGA_AGGREGATE_TARGET is set to PGA_TARGET_FOR_ESTIMATE. A nonzero value means that PGA_TARGET_FOR_ESTIMATE is not large enough to run the work area workload. Hence, PGA_AGGREGATE_TARGET should not be set to PGA_TARGET_FOR_ESTIMATE since Oracle will not be able to honor that target. |
