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SQL Server의 데이터베이스는 데이터 파일과 로그 파일로 구성됨.

로그 파일은 앞에서 설명한 VLF로 구성된다.

반면, 데이터 파일의 가장 작은 단위는 페이지이다.

연속적인  8개의 페이지로 extent가 구성된다.

extents는 'single-extent' (균일 익스텐트), 'mixed extent'(혼합 익스텐트) 로 나뉜다.

균일 익스텐트는 하나의 개체가 8개의 페이지를 모두 사용 하며, 혼합 익스텐트는 하나의 익스텐트에 여러 개체가 들어간다.

테이블을 만들때는 익스텐트 단위로 일어나는데 SQL은 처음 테이블을 만들때는 항상 혼합 익스텐트 내에서 생성한다.

테이블이 커져가서 8 개의 page를 채훈 후 부터 균일 인스텐트를 할당한다.

* GAM, SGAM

SQL Server는 전역 할당 맵(GAM) 과 공유 전역 할당 맵(SGAM) 이라는 두가지 할당 맵을 사용하여 익스텐트, GAM, SGAM은 각 1bit로 하나의 익스텐트를 관리함으로 총 6400 익세텐트를 관리 (4GB)

GAM : 어떤 익스텐트가 할당되었는지 관리

SGAM : 어떤 익스텐트가 현재 혼합 익스텐트로 사용되는지, 빈 페이지를 가지는지 여부 관리

SGAM : 1인것이 존재 하지 않으면, 1:0 인것을 찾아서 할당하고 비트 패턴을 0:1 로 변경한다.

2. GAM과 SGAM은 데이터 파일 하나씩 있으므로 해당 DB의 파일 개수를 늘려주면 SGAM에 대한 요구가 분산되어 보다 좋은 성능을 낼 수 잇다.

임시테이블은 모두 tempdb에서 처리됨으로 tempdb의 데이터 파일을 여러개로 분리하는 것이 많은 수의 임시 테이블 요구에 대한 할당 잠금 측면에서 유리하다.

* PFS (Page Free Space)

힙, ntext, text, image 컬럼의 페이지가 할당되었는지 여부와 각 페이지의 빈 공간 크기를 기록한다.

하나의 PFS 페이지는 약 8000 page = 1000 익스텐트 관리하며, 파일이 커지면 연결 리스트 구조로 새로운 PFS 페이지가 추가된다.

* BCM (Bulked Change Map)

마지막 Backup log 문 이후 대량 기록 작업에 의해 수정된 익스텐트를 관리, 대량 로그 복구 모델일 때 사용됨

* DCM

마지막 bakcup dataase (full backup) 이후에 변경된 익스텐트를 관리하는 페이지이며, 차등 백업의 대상 익스텐트를 찾기 위해 사용,

BCM, DCM도 1bit로 하나의 익스텐트를 관리함으로 총6400 익스텐트 관리하게 된다.

* IAM (Index Allocation Map)

개체가 사용하는 데이터베이스 파일의 익스텐트를 매핑한다.

SQL Server DBA Checklist

 Problem
I am looking for items that I should address on a daily basis on my SQL Servers.  As such, what are the critical aspects of SQL Server that should I check on a daily basis?  Should I perform additional checks on a weekly, monthly or yearly basis?  How can I automate some of these tasks so I do not spend my whole day reviewing SQL Servers rather working on the latest and greatest technologies?

Solution
Depending on your environment dictates all of the items that should be reviewed on a daily basis as well as their criticality in your specific organization.  Based on your environment, customize the list below to ensure it meets your needs:

Daily Checklist

• Backups - Check your backups to validate that they were successfully created per your process.
  • MSSQLTips.com Category: Backup and Recovery
• Nightly Processing - Review the nightly or early morning processes.
• SQL Server Error Log - Review the SQL Server error log for any errors or security issues (successful or failed logins) that are unexpected.
  • SQL Server 2005 Exposed - Log File Viewer
• Windows Event Log - Review the Application Event Log at a minimum to find out if any Windows or hardware related errors or warnings are being written.
  • Some of the hardware vendors write warnings to the Windows Event Log when they anticipate an error is going to occur, so this gives you the opportunity to be proactive and correct the problem during a scheduled down time, rather than having a mid day emergency.
  • SQL Server 2005 Exposed - Log File Viewer
• SQL Server Agent Jobs - Review for failed SQL Server Agent Jobs.
  • Finding SQL Server Agent Job Failures
• HA or DR Logs - Check your high availability and/or disaster recovery process logs.  Depending on the solution (Log Shipping, Clustering, Replication, Database Mirroring, CDP, etc.) that you are using dictates what needs to be checked.
• Performance Logs - Review the performance metrics to determine if your baseline was exceeded or if you had slow points during the day that need to be reviewed.
  • MSSQLTips.com Category: Performance Tuning
• Security Logs - Review the security logs from a third party solution or from the SQL Server Error Logs to determine if you had a breach or a violation in one of your policies.
• Centralized error handling - If you have an application, per SQL Server or enterprise level logging, then review those logs for any unexpected errors.
  • Standardized Error Handling and Centralized Logging
• Storage - Validate you have sufficient storage on your drives to support your databases, backups, batch processes, etc. in the short term.
• Service Broker - Check the transmission and user defined queues to make sure data is properly being processed in your applications.
  • MSSQLTips.com Category: Service Broker
• Corrective Actions - Take corrective actions based on the issues and/or errors that you found.
• Improvements - Look for opportunities to improve your environment based on the review and analysis you have performed.
• Learn something new - Although this review and correction process could be time consuming, take some time every day to learn something new to improve your knowledge of the technology you work on every day.

Weekly or Monthly Checklist

• Backup Verification (Comprehensive)- Verify your backups and test on a regular basis to ensure the overall process works as expected.  What is meant by this is to:
  • Contact your off site tape vendor to obtain a tape
  • Validate that the tape goes to the correct office
  • Validate that the vendor delivers the correct tape
  • Validate that the vendor delivers the tape in the correct time period
  • Validate that the software version you use to perform the restore is compatible with the version from the tape
  • Validate that the tape does not have any restore errors
  • Validate that sufficient storage is available to move the backup to the needed SQL Server
  • Validate that the SQL Server versions are compatible to restore the database
  • Validate that no error messages are generated during the restore process
  • Validate that the database is accurately restored and the application will function properly
• Backup Verification (Simple) - Verify your backups on a regular basis.
  • Maintenance Tasks: Automating the RESTORE VERIFYONLY Process
  • Verifying Backups with the RESTORE VERIFYONLY Statement
• Windows, SQL Server or Application Updates - Check for service packs/patches that need to be installed on your SQL Server from either a hardware, OS, DBMS or application perspective
  • MSSQLTips.com Category: Service Packs / Patches
• Capacity Planning - Perform capacity planning to ensure you will have sufficient storage for a specific period of time such as for 6, 12 or 18 months.
  • Easing the Capacity Planning Burden
• Fragmentation - Review the fragmentation for your databases to determine if you particular indexes must be rebuilt based on analysis from a backup SQL Server.
  • MSSQLTips.com Category: Fragmentation
• Maintenance - Perform database maintenance on a weekly or monthly basis.
  • MSSQLTips.com Category: Maintenance
• Security - Remove unneeded logins and users for individuals that have left the organization, had a change in position, etc.
• Shrink databases - If databases or transaction logs are larger, than necessary shrink those files to free up disk space.
  • SQL Server 2000 to 2005 Crosswalk - Database Maintenance Plan Wizard to SQL Server Integration Services (SSIS)

Opportunities for Automation

• Setup alerts for specific error levels or error messages that impact your SQL Servers in order to be notified automatically.
  • Database Backup and Restore Failure Notifications
• Setup Jobs to query for specific conditions in your tables to validate data was loaded or data is being added to specific tables based on your business processes throughout the day.
• Setup notification on Job success, failure or completion.
  • One word of warning is to check your business critical Jobs on a regular basis just to be sure they are working properly.  Nothing is worse than finding out a key process has been failing for days, weeks or months and the reason notifications have not been sent are due to an incorrect configuration, full mailbox, etc.  It may be 30 minutes on a weekly basis that is time well spent.
• Setup centralized error handling on a per SQL Server, application or enterprise basis then determine the business rules for specific error conditions.

http://www.microsoft.com/korea/eseminar/Seminar_player7.aspx?number=1316&asf=300K

온라인 등록하고 들으면 들을 수 있습니다.

출처 http://www.mssqltips.com/tip.asp?tip=960

비교적 쉬운 영어길래 그대로 가져옵니다.

Problem
SQL Server offers the ability to use startup parameters when your SQL Server instance starts. The default items include:

• location of  master database data file (-d)
• location of  master database log file (-l)
• location of  SQL server error logs (-e)

In addition, you can set startup parameters for trace flags, starting your instance in single user mode, etc...here is a link to startup options for SQL Server 2005 which is pretty similar to options for SQL Server 2000.

With SQL Server 2000 the startup parameters are available right from Enterprise Manager, but not so with SQL Server 2005.  So how do you set the startup parameters for SQL Server 2005?

Solution
With SQL Sever 2000 access to the startup parameters is available right within Enterprise Manager.  You can get to the startup parameters by right clicking on the server name and selecting "Properties".  The following screen appears and there is a great big button "Startup Parameters..." which you can click and it will allow to see and set the startup parameters.

After clicking on "Startup Parameters" you get the following window.  From here you can click on the parameter and click "Remove" to remove it or click on "Add" to add a new parameter. It is pretty straight forward.

With SQL Server 2005 a lot of things have been moved to other applications and are not all available through SQL Server Management Studio.  One of these things is the startup parameters.  To find the startup parameters you need to go to the SQL Server Configuration Manager tool.  This can be found in the menus through: Microsoft SQL Server 2005 -> Configuration Tools -> SQL Server Configuration Manager.

Once the application is launched you will see the following screen.

• select the SQL Server service that you want to set the startup parameters for such as "SQL Server (TEST1)" for our example
• right click and select "Properties" and the following window will pop up
• go to the "Advanced" tab

• select "Startup Properties" and the following window will pop up

• from here you can add, change or remove your startup properties
• note: each startup parameter is separated by a semi colon (;)
• once you are done click "Apply" to save your changes

좋은 소식!!

이제 2005, 2008의 스탠다드 에디션에서도 Locak Page Memory 사용이 가능해 졌다.

CU2 for SQL Server 2008 SP1 => http://support.microsoft.com/kb/970315/en-us

http://support.microsoft.com/kb/970279/ko
CU4 for SQL Server 2005 SP3 => http://support.microsoft.com/kb/970279/en-us

http://support.microsoft.com/kb/970279/ko