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 rows 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 NAME='INDEX_NAME';
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 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 how 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.
您可能感兴趣的文章:- MSSQL 大量数据时,建立索引或添加字段后保存更改提示超时的解决方法
- mssql 建立索引
- SQLSERVER全文目录全文索引的使用方法和区别讲解
- SQL_Server全文索引的使用实例演示
- mysql 添加索引 mysql 如何创建索引
- sqlserver 索引的一些总结
- SQL Server 索引介绍
- sqlserver索引的原理及索引建立的注意事项小结
- 用SQL建立索引的方法步骤
- MSSQL自动重建出现碎片的索引的方法分享
