關於Oracle 11g 統計資訊的收集

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關於Oracle 11g 統計資訊的收集

1.對於 ANALYZE 請不要再使用compute 、estimate 選項,他們已經被廢棄了。

此外analyze 搜集的統計資訊不能被cost-based optimizer最佳化器所使用,只能在以下情形使用:

for statistics collection not related to the cost-based optimizer, such

as:

■ To use the  VALIDATE  or  LIST  CHAINED  ROWS clauses

■ To collect information on freelist blocks

must use the ANALYZE statement to collect statistics

unrelated to the optimizer, such as em pty blocks, average space, and so forth.

2.DBMS_STATS

可以並行的搜集統計資訊,為分區對象搜集全域的統計資訊。而cbo實際上只使用

dbms_stats搜集的統計資訊。

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