will compressing my indexes improve performance ?
压缩索引会提高性能么? 【程序编程相关:(原创)飘浮广告显示脚本类(VBS,JS】 【推荐阅读:在C#中应用哈希表(Hashtable)】author´s email: jonathan@jlcomp.demon.co.uk 【扩展信息:VB连接数据库时出现“ActiveX部件】
author´s name: jonathan lewis
date written: 26th feb 2003oracle version(s): 8.1 - 9.2
compressed indexes have been around for a couple of years now - but will compressing your indexes automatically improve performance ?
压缩索引已经存在好几年了——那么压缩索引会自动提高性能么?oracle introduced a compression option for indexes in oracle 8.1. you can create an index as compressed, or rebuild it to compress it (although there are some restrictions about online rebuilds, rebuilds of partitioned indexes etc.) typical syntax might be:
oracle在oracle 8.1中引入了索引的压缩特性.你可以创建一个压缩索引,或者重建时压缩一个索引(尽管对在线重建.重建分区索引等有一些限制).标准语法如下:create index t1_ci_1 on t1(col1, col2, col3, col4) compress 2;
alter index t1_ci_1 rebuild compress 2;
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