pctfree對 index索引在什么時候有效? -开发者知识库

pctfree對 index索引在什么時候有效? -开发者知识库,第1张

 pctfree only counts when BUILDING an index.  It reserves X% of the block for subsequent
inserts into that block (inserts into the block can arise from inserts or UPDATES to the
base table).
All the pctfree does on an index is defer the splitting of an index block due to
subsequent inserts/updates AFTER the index is build.  10% is just a good "starting
point".
 
      與表的pctfree值不同,對於索引來說,其pctfree僅僅是在create或rebuild時生效,對與后續的插入、修改之類的操作來說是無效的,pctfree的設置也僅僅是為了延緩由於insert等操作而導致的的索引塊分裂。

最佳答案:

本文经用户投稿或网站收集转载,如有侵权请联系本站。

发表评论

0条回复