Re: question regarding statistics

Bryan Wells wrote:

>i may have asked this once before, so if it is indeed redundant i appologize:
>
>is there a difference in analyze and compute statistics?
>
>

You probably mean whether there is adifference between DBMS_STATS and analyze. There are several,
differences and we can divide them in two groups:

1. Performance differences DBMS_STATS can utilize PQ. Analyze can not.
2. Essential differences DBMS_STATS package can gather global statistics at multiple levels as specified by the granularity parameter. In contrast, the legacy ANALYZE command collects statistics only at the lowest level and derives higher level statistics by aggregation. These aggregated statistics are sometimes less accurate than the global statistics since it is not possible to precisely determine the overlap of values across partitions. Statistics for the number of distinct values and density are particularly susceptible to inaccuracy DBMS_STATS can populate auxiliary statistics, needed for CPU costing. Analyze can not.

More detail in Note:114671.1

-- 
Mladen Gogala
Oracle DBA
Ext. 121


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