You observe that suboptimal execution plans for the queries are being generated on a table that previously used less resources. You have collected statistics on these tables two days ago. The optimizer statistics retention period is set to 31 days. You are able to find the timestamp information about statistics update from the DBA_TAB_STATS_HISTORY view. Because it is a frequently queried table, you would like the optimizer to generate better plans. Which action would enable you to use the previous set of statistics on the objects that may lead to better execution plans?
A. restoring statistics from statistics history up to the desired time
B. deleting all AWR snapshots collected after the time of desired statistics collection
C. applying the flashback table technique until the time of desired statistics collection
D. setting the OPTIMIZER_PENDING_STATISTICS parameter to TRUE to use the previous version of statistics
Answer:A
You observe that suboptimal execution plans for the queries are being generated on a table that previously used less resources. You have collected statistics on these tables two days ago. The optimizer statistics retention period is set to 31 days. You are able to find the timestamp information about statistics update from the DBA_TAB_STATS_HISTORY view. Because it is a frequently queried table, you would like the optimizer to generate better plans. Which action would enable you to use the previous set of statistics on the objects that may lead to better execution plans?
A. restoring statistics from statistics history up to the desired time B. deleting all AWR snapshots collected after the time of desired statistics collection C. applying the flashback table technique until the time of desired statistics collection D. setting the OPTIMIZER_PENDING_STATISTICS parameter to TRUE to use the previous version of statistics