[Teradata] Teradata Architecture

개요

Teradata는 분산된 구조를 가지며 크게 4가지 요소로 이루어져있다.

1. 사용자가 SQL을 전달하면 Parsing Engine(PE)에서 Security Check 및 Syntax Check를 진행한 후 Access Module Processors(AMP)들을 위한 실행 플랜을 세우며,
2. 이때, AMP는 실행 플랜에 필요한 만큼 데이터를 전달하고
3. 각 AMP는 쿼리 결과를 spool space에 임시로 저장한 후, 사용자에게 넘김

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Tearadata 구조

1. Parsing Engine(PE)

• 세션 관리
• 사용자가 요청한 SQL문의 Syntax 체크
• 사용자가 접근 요청한 테이블에 대한 권한이 있는지 체크
• AMP가 수행할 실행 계획을 세움

2. Access Module Processors(AMP)

• The AMP is a virtual processor in the Teradata Databases which have shared-nothing architecture and are responsible for managing a portion of the database. Each AMP will manage their own disk.

3. BYNET

• There are always two BYNETs for redundancy and extra bandwidth
• AMPs and PEs can use both BYNETs to send and retrieve data which in turn fastens the response time.

4. Disk

• These are actual physical data storage units which are accessed/manipulated by AMPs on user requests

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Teradata Space

Permanent Space

• Permanent space is the maximum amount of space allocated to the user/database to hold data rows.
• Perm space is used for database object (permanent tables, indexes etc) creation and to hold their data.
• The amount of permanent space is divided among the number of AMPs.Whenever per AMP limit exceeds the allocated space of AMP, 'No more room in database' error message is generated.

Spool Space

• Spool space is the unused permanent space which is used by the system to keep the intermediate results of the SQL query.
• Users without spool space cannot execute any query.
• Data is active up to the current session only.
• Spool space is divided among the number of AMPs. Whenever per AMP limit exceeds the allocated space, the user will get a spool space error.

Temporary Space

• Temporary space is the unused permanent space which is used by Global Temporary tables.
• Temp space is also divided by the number of AMPs.
• Data is active up to the current session only.
• Temp space is reserved prior to spool space for any user defined operation.
• Temp space is allocated at the database or user level, but not the table level.

조회 Query

SELECT DatabaseNameI
	 , PermSpace
	 , SpoolSpace
	 , TempSpace
	 , CreateTimeStamp
  FROM DBC.DBase 
 WHERE DatabaseNameI = '[databasename]';