Internals

关于Partial write for all MySQL and Oracle

September 2, 2014 Internals, MYSQL, oracle No comments

很久之前看过这个帖子,当时没有细究,这几天看了下mysql相关的internal 突然想起这个问题,跟三四个朋友讨论了下 想把这个问题展开讲一讲。

源帖子内容见:https://community.oracle.com/thread/1087650?start=0&tstart=0

这个[……]

Read more

[转] Autotrace with bind variables

September 27, 2013 Internals, oracle No comments

JL刚刚写的一篇autotrace与bind variables 的行为:Autotrace trick
之前我们也发现过这个问题具体SR在这里:something seems confused [……]

Read more

CTAS导致严重BUG一则

September 25, 2013 Internals, oracle No comments

某国内巨头的一起CASE,在系统繁忙情况下大量的CTAS 导致数据字典表的不一致,由原来10.0.2.4版本升级到10.0.2.5之后问题依旧。
具体表现为:
1. 尝试drop这些不一致的tablespace

15:00:18 SQL> @dropts_2012.0319.150[......]

Read more

Think of bind value

September 17, 2013 Internals, oracle No comments

[……]

Read more

一次诡异的缓慢”死亡” CASE

September 13, 2013 Internals, oracle No comments

今天下午遇到的一个诡异CASE,现象为系统诡异的死亡,目前判定为sqluldr2工具导致 (同事使用sqluldr2 用具 执行了sqluldr2_linux64_10204.bin -help 命令)
抛出的错误如下 (/var/log/message)

Sep 11 09:00:54[......]

Read more

How to control CF calculation

May 14, 2013 Internals, oracle No comments

根据Richard Foote的文章,做了如下验证:

RefClustering Factor Calculation Improvement and provide some control over DBMS_STATS index clustering factor computat[……]

Read more

Block split and entry reorder

December 12, 2012 Internals, oracle No comments

今天跟研发的同学讨论到了这个问题,index block split过程中涉及到的重新排序问题.

SQL> create table idx_split (a number, b varchar2(1446), c date);   
 
Table created
 

SQ[......]

Read more

Scripts: dbms_backup_restore modify dbid and db_name

December 5, 2012 Internals, oracle 1 comment

Scripts:dbms_backup_restore_dbid

eg:

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Par[......]

Read more

Oracle Bind Graduation 测试

November 28, 2012 Internals, oracle No comments

最近team 讨论 Bind Graduation 比较激烈,详细可以见上一篇文章,基于Bind Graduation 做了以下测试:

主要目的:

测试基于OCI JDBC 等接口的 Bind Graduation行为.针对目前Bind Graduation的行为,以及11.2.0.[……]

Read more

Exchange outlines

September 14, 2012 Internals, oracle No comments

参见昨天Roger的文章,exchange outline可以同样实现这种需求

参考JL的文章:
Stored Outlines in Oracle 8
Stored Outlines in Oracle 9

测试环境:rhel 5.8 oracle 11.2.0.3 64bit[……]

Read more