Goodbye Randy Pausch

颱風夜裡傳來不好的消息,從Google官方部落格得知,The Last Lecture作者Randy Pausch教授已於昨晚過世,得年47歲。Randy Pausch著名的最後演說,以及後來出版成書的演說內容,已經透過影像和文字流傳全世界,讓大家能永遠的懷念這位教授。


SQL server清除記憶體和cache的方法

SQL server只要開久了,server的記憶體常常會被吃滿,需要重新reboot server來釋放記憶體。SQL server提供下面三個指令,允許在server不重開的情況下(尤其是production環境),釋放記憶體和清除cache。







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SQL server取得所有table資料筆數的方法

以下指令可以查詢SQL server資料庫所有table的資料筆數 (由大到小排列)。可以很快知道資料筆數大的table,並做進一步管理。

select, i.rows
from sysobjects o inner join sysindexes i on =
where i.indid = 1
order by i.rows desc

另一個好用的store procedure是sp_spaceused,這個指令可以查詢某個table目前的資料筆數和資料所佔的硬碟空間,指令如下:

exec sp_spaceused 'TABLE NAME'



過去的工作經驗中,在專案團隊中雖然有DBA(Database administrtor)這個角色,常常很多人對DBA要做些什麼不是非常清楚。因為,在一般的中小型專案,為了靈活運用人力資源,DBA除了要做資料庫管理的工作之外(大概是因為真的沒有那麼多資料庫可以管),還得兼做系統管理或者後端資料整合的工作。甚至在台灣的一般公司行號當中,似乎不常聽聞有DBA這樣的職位,而多以系統工程師做DBA的工作,反而國外或外商公司較多專職做DBA工作的人,也許是他們的工作分工較細吧。

我找到資料庫專家Pinal Dave在部落格中的一篇文章並摘錄如下(日後有空會嘗試將其翻譯成中文),裡頭提到DBA的工作執掌,需具備經驗和技能,也許可以提供大家在求職和生涯規劃的參考。
DBA Job Description

The Data Base Administrator (DBA) is responsible for providing technical support for the database environment including overseeing the development and organization of the databases, assessment and implementation of new technologies, and providing Information Technology with a long-term perspective on the relationship of database technology to the business opportunities facing the company. It is extremely important to the company that on-line processing database systems offer the highest reliability and performance possible. The DBA is challenged to work with architecture, application development and operations to help achieve a state-of-the-art environment that meets current and future business objectives. Trains and develops technical support and applications staff to better utilize on-line processing databases environment. Provides and designs tools to assist in the management of the database and transaction processing environment.Works to provide a working model of our transaction processing environment for capacity assessment and planning.

Develops a methodology for the ongoing assessment of database performance and the identification of problem areas. Develops a security scheme for the database environment, as well as assisting in disaster recovery if necessary. Provides leadership during the development and enhancement of production applications including working with applications, technical support and operations during the design, development and implementation of applications. Work with the transaction processing area to develop both the physical and the logical database administration functions and assists in the development of our processing database and computing environments. Work with others in IT to build the logical database area and provide technical guidance during all phases of the development process. Work with vendors in evaluating and implementing new technologies.

Required Experience

  • BE or BS Degree in one of the following subject areas: Computer Science, Business Administration, Information Technology or related field preferred

  • 2 -3 years IT operation with strong understanding of database structures, theories, principles, and practices

  • 3-5 years Microsoft SQL Server experience

  • Understanding of, and experience with, server-client computing and relational database environments

  • Experience with data management and data processing flowcharting techniques

  • Knowledge of reporting and query tools and practices

  • Good understanding of the organizations goals and objectives

  • Good interpersonal, written, and oral communication skills

  • Technical documentation skills

  • Ability to present ideas in user-friendly language

  • Self motivated and directed, with keen attention to detail

  • Able to prioritize and execute tasks in a high-pressure environment

  • Experience working in a team-oriented, collaborative environment

  • Good written and oral communication skills

Required Skills

  • SQL Server 2005

  • Database Administration

  • Database Tuning

  • Database Management

  • Database Security


  • Bachelor’s Degree

Reference : Pinal Dave (


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