How to find sql with need bind(from asktom)
Lbrary cache latch contention is typically caused by NOT using bind variables. It is due to excessive parsing of statements.One way to see if this might be the case in your situation is to run a script like:create table t1 as select sql_text from v$sqlarea;alter table t1 add sql_text_wo_constants varchar2(1000);create or replace function remove_constants( p_query in varchar2 ) return varchar2as l_query long; l_char varchar2(1); l_
Some tips on views (from asktom)
The finaly question becomes what is worse for perforamnce,is simple -- "doing things to protect programmers, who are paid to write code for money and do it right, is the worst thing you can do for performance"In my world -- views are implemented for single use things. When I build a view, it is for an application. I tend to not use a generic view for everything. I create a view much like people create subroutines -- for a PURPOSE.So, i will pick neither of 1 or 2 from your first l
Setup two listener.
Setting up multiple Listeners I. Setting up Two Listeners for one Instance Same Machine Main Listener file is located in %ORACE_HOME%networkADMIN directory. Default listener filename is listener.ora. To add multiple listeners, listener name, ie must first add in the listener.ora file. Then start the listerner from listerner.ora. In this example, listeners are located in the same machine. Sample two listeners configuration
v$log.status的一点概念(zt from oracle-l)
http://email@example.com/msg90348.htmlThis makes sense if you think about where the various v$ dynamic performance views get their info from, and which Oracle background process is responsible for each task. First, note that: 1. v$log.status gets its redo log info from the *control file* 2. v$datafile_header.checkpoint_change# and checkpoint_time get their info from the *datafile headers*. Here's the sequence of events when a log switch happens: 1.
How to update aggregate history Info(zt from asktom)
You Asked (Jump to Tom's latest followup)Hi Tom,We have a busy OLTP database that shares many schemas for many applications. A workflow application has a dbms job that runs every 5 minutes. Here is what it does:1. delete from <a wide de-normalized summary table>;2. insert into <this de-normalized summary table> select * from <a code table>, < inline view with sum(case when..) as period1,... ... sum(case when ...) as period10, c
all about user account status
Oracle的用户帐户管理里面大有学问了, 控制非常灵活, 设计非常精巧, 如果我们能够在我们自己的数据库应用程序中应用这种技术, 相信用户也会非常开心的^_^.用户的Accountstatus一共有一下几种情况.SQL> select * from user_astatus_map; STATUS# STATUS ---------- -------------------------------- 0 OPEN 当前帐户是开放的用户可以自由登录 1