根据Richard Foote的文章,做了如下验证:
Ref:Clustering Factor Calculation Improvement and provide some control over DBMS_STATS index clustering factor computation
[oracle@db-42 ~]$ unzip p13262857_112030_Generic.zip
[oracle@db-42 ~]$ cd 13262857/
[oracle@db-42 13262857]$ ora si
SQL*Plus: Release[......]Read more
前天处理了一启RAC ASM 内存泄露问题,系统为公司最后一套RAC one node 版本为11.2.0.3
这套核心RAC one node系统出现大量 log file switch buffer busy waits等待,并伴随大量cursor: pin S wait on X read by other session。
SID USERNAME MACHINE EVENT PARAM W WT SQL[......]Read more
最近team基于mysql的性能基准测试,包含多种场景[……]
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Database-exporter发布 感谢wucharles,一个充满Geek精神的小伙。
1.supports export database from each other. (you need write driver by yourself,now support oracle and MySQL)
2.supported database: Oracle, MySQL.(from oracle to mysql or mysql to oracle)
3.supports multi source tables merged into one target ta[......]Read more
首先我们看一组测试 数据库版本oracle 12c beta1
SQL> select count(*) from test;
COUNT(*)
----------
725888
SQL> set timing on;
SQL> alter table test add name varchar(20) default 'liu';
Table altered.
Elapsed: 00:00:00.02
Elapsed: 00:00:00.01
SQL> alter table[......]Read more
根据JL,Glen Fawcett 的文章 oracle 从12c开始提供了3个视图来探测慢速的IO
SQL> desc V$LGWRIO_OUTLIER;
Name Null? Type
----------------------------------------- -------- ----------------------------
FUNCTION_NAME VARCHAR2(18)
IO_SIZE NUMBER
WAIT_EVENT VARCHAR2(64)
FILE_NA[......]Read more
www.yhddba.com (主站点)
www.yihaodiandba.com (备份站点 会有一天的延迟)
同时开通访问,主要记录日常的一些问题处理,以及针对互联网的数据架构想法。[……]
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