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Database

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[HANA] HANA DB Trace Trace Structure Trace entries ([_] 공백으로 구분) []{}[/] :
[HANA] 유용한 Python 프로그램 http://sapbasisinfo.com/blog/2018/03/12/useful-python-scripts-for-hana/ All python scripts can be found in exe/python_support directory. These scripts can affect the system therefore it’s better to check with ‘-help’ switch before executing the scripts. systemOverview.py You can get system information with this script like Instance, Services, Memory, Disk, Memory etc. python systemOverview.py Ex..
[HANA] HANA DB Startup DB Startup overview HDB daemon startup overview Runlevel 1-2 Runlevel 3-5 Indexserver Startup Overview Core/CPU Information Collection Persistency Initialization Row Store Log Replay DTX (Distributed Transaction) Consistency Check / How it work? DTX Consistency Check : 분산 트랜잭션을 위한 트랜잭션의 정합성 체크 Terminology LSN (Log Sequence Number) Log 위치를 가리킴 DTX Consistency에서 LSN은 Log Position 대신 사용 Master & Sl..
[HANA] Parameter - service_thread_sampling_monitor_enabled HANA Thread M_SERVICE_THREADS Current thread M_SERVICE_THREADS_SAMPLES History of thread Retention = at least 2 hours HOST_SERVICE_THREAD_SAMPLES Only available if embedded statistics server is used Retention = 1 day ~ 42 days Command Deactivate data collection UPDATE _SYS_STATISTICS.STATISTICS_SCHEDULE SET STATUS = 'Inactive' WHERE ID = 5034 Activate data collection UPDATE _SYS_STATISTICS.STATI..
[HANA] Parameter - expensive statement 관련 Expensive statement로 저장되는 기준 Indicator Validity Parameter Unit Details Runtime general threshold_duration us SQL statements exceeding the configured runtime limit are recorded. CPU consumption Rev. >= 94 threshold_cpu_time SQL statements exceeding the configured CPU consumption are recorded. As a prerequisite CPU time measurement must be activated on SAP HANA
[HANA] Parameter 정리 보호되어 있는 글입니다.
[HANA] HANA Temporary Table Temporary Table Overview 실생시에 생성되고 일반 테이블이 하는 모든 operation의 모든 든 종류를 수행할 수 있음 범위는 다음과 같이 제한 됨 Temp lets you store and process intermediate results Temp tables only last as long as the session is alive Data in temp tables is automatically deleted at the end of the database session, event if it ends abnormally 2가지 Type 존재 Global Temporary Table Table definition is globally available to any connect..
[HANA] Column store index HANA Index Types Primary key index 대부분의 테이블에는 primary key 존재 -> 개별 행마다 고유한 식별자 제공 보통 여러 개의 attribute로 구성 Column store에서는 각 primary key를 위해 자동으로 여러개의 인덱스를 생성 A Table with primary key (MANDT, KNR, RNR) -> 분리된 inverted index on MANDT, on KNR, on RNR Column dictionary가 이미 정렬되어 있는데 인덱스가 필요한 이유는? Dictionary를 읽은 후에 결국은 Attribute Vector를 모두 읽어야 함 이를 개선하기 위한 inverted index Secondary Index 각 행별로 고유 식별자를 제..