You have a range-partitioned table in your database. Each partition in the table contains the
sales data for a quarter. The partition related to the current quarter is modified frequently and
other partitions undergo fewer data manipulations. The preferences for the table are set to
their default values. You collect statistics for the table using the following command in regular
intervals:
SQL> EXECUTE DBMS_STATS.GATHER_TABLE_STATS(‘SH‘,‘SALES‘,GRANULARITY=>‘GLOBAL‘);
You need statistics to be collected more quickly. What can you do to achieve this?
A. Set DYNAMIC_SAMPLING to level 4.
B. Set the STATISTICS_LEVEL parameter to BASIC.
C. Set the INCREMENTAL value to TRUE for the partition table.
D. Increase the value of STALE_PERCENT for the partition table.
Oracle will update the global table statistics by scanning only the partitions that have been
changed instead of the entire table if the following conditions hold:
INCREMENTAL value for the partitioned table is set to TRUE
PUBLISH value for the partitioned table is set to TRUE;
User specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when
gathering statistics on the table
If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table
scan is used to maintain the global statistics which is a much more resource intensive and timeconsuming operation for large tables.
默认情况下 INCREMENTAL 为 false，如果将其设置为 true，那么在搜集信息时， oracle 只
扫描改变的分区，这样搜集信息就会变得更快。故选 C，正确
参考： http://docs.oracle.com/cd/E11882_01/appdev.112/e40758/d_stats.htm#ARPLS68595
