DB Time 占 DB CPU的比重: 7.1/11.7= 60.68% --"Top 5 Timed Events"中关于DB CPU的描述 按照CPU/等待事件占DB Time的比例大小,这里列出了Top 5。如果一个工作负载是CPU繁忙型的话,那么在这里应该可以看到 DB CPU的影子。 *注意到,我们刚刚已经算出了DB CPU 的%DB time,60%。其它的external table read...
To view the Installation OBE, in your browser, enter the following URL: http://www.oracle.com/webfolder/technetwork/tutorials/obe/db/ 11g/r2/2day_dba/install/install.htm 2-22 Oracle Database 2 Day DBA 3 3 Getting Started with Database Administration This chapter provides a brief roadmap ...
no rows selected scott@DB01> select rownum,demono,ename,sal from demo where rownum>3; no rows selected 如果我们想要查询结果集中的某一段范围的记录,比如5-10条的记录,该如何查询呢?很多开发人员把这样的需求称为分页 scott@DB01> select rownum,demono,ename,sal from demo where rownum between 5 and...
2、 索引信息数据 > select * from (select index_name,num_rows,leaf_blocks,clustering_factor from dba_indexes order by 4 desc nulls last) where rownum<11; 索引的基本信息,输出包括叶块数和聚簇因子等,如聚簇因子接近行数可能代表索引效率不高。 3、 DBlink信息 > select * from dba_db_links; Beth...
chain_cnt :Number of rows in the table that are chained from one data block to another or that have migrated to a new block, requiring a link to preserve the old rowid. This column is updated only after you analyze the table. 数据缓冲区命中率(百分比小于90就要加大db_cache_size) 查询V$...
whereround(del_lf_rows/decode(lf_rows,0,1,lf_rows)*100,0)>30; 集群因子clustering_factor高的表 集群因子越接近块数越好,接近行数则说明索引列的列值相等的行分布极度散列,可能不走索引扫描而走全表扫描 代码语言:javascript 代码运行次数:0
数据缓冲区命中率(百分比小于90就要加大db_cache_size) 查询V$SYSSTAT视图可以查看从内存中读取数据的频率。它提供了数据库中设置的数据块缓存区的命中率。这个信息可以帮助您判断系统何时需要更多的数据缓存(DB_CACHE_SIZE),或者系统的状态何时调整得不佳(二者均将导致较低的命中率)。
select tab.owner,tab.table_name,tab.blocks,tab.num_rows,ind.index_name,ind.clustering_factor, round(nvl(ind.clustering_factor,1)/decode(tab.num_rows,0,1,tab.num_rows),3)*100||'%' "集群因子接近行数" from dba_tables tab, dba_indexes ind where tab.table_name=ind.table_name and tab...
Oracle® HTML DB User's Guide Release 1.6 Part No. B14303-02 March 2005 Oracle HTML DB User's Guide, Release 1.6 Part No. B14303-02 Copyright © 2003, 2005, Oracle. All rights reserved. Primary Author: Terri Winters Contributors: Carl Backstrom, Christina Cho, Michael Hichwa Joel ...
Get rowsOperation ID: GetItems This operation gets rows from a table. Parameters Izvērst tabulu NameKeyRequiredTypeDescription Table name table True string Name of Oracle table Filter Query $filter string An ODATA filter query to restrict the entries returned (e.g. stringColumn eq '...