导读:1建站知识经常需要在Oracle中检查是否需要重构索引，在此写了个示例语句，有此需求的朋友可以参考下，希望对大家有所帮助如何seo优化推广网站seo网站优化培训。

复制代码 代码如下:

SELECT height, /*Height of the B-Tree*/ blocks, /* Blocks in the index segment */ name, /*index name */ lf_rows, /* number of leaf ro网站建设哪家好ws in the index */ lf_blks, /* number of leaf blocks in the index */ del_lf_rows, /* number of deleted leaf rows in the index */ rows_per_key /* average number of rows per distinct key */ blk_gets_per_access /* consistent mode block reads (gets) */ FROM INDEX_STATS WHERE;

复制代码 代码如下:

ANALYZE index INDEX_NAME VALIDATE STRUCTURE

HEIGHT: This column refers to the height of the B-tree index, and it's usually at the 1, 2, or 3 level. If large inserts push the index height beyond a level of 4, it's time to rebuild, which flattens the B-tree. DEL_LF_ROWS: This is the number of leaf nodes deleted due to the deletion of rows. Oracle doesn't rebuild indexes 网站建设多少钱automatically and, consequently, too many deleted leaf rows can lead to an unbalanced B-tree. BLK_GETS_PER_ACCESS: You can look at the BLK_GETS_PER_ACCESS column to see h建设网站ow much logical I/O it takes to retrieve data from the index. If this row shows a double-digit number, you should probably start rebuilding the index.相关如何seo优化推广网站seo网站优化培训。

关键词标签: 索引 重构