전체 글 (198) 썸네일형 리스트형 [HANA] High availability support Overview HANA Supports Disaster recovery support Backups : Periodic saving of database copyes in safe pace Storage replication : Continuous replication (mirroring) between primary storage and backup storage over a network (may be synchronous) System replication : Continuous update of secondary system by primary system, including in-memory table loading Fault Recovery support Service auto-restart.. [HANA] SAP Notes 2600030 - Parameter Recommendations in SAP HANA Environments Symptom You are interested in parameter recommendations for SAP HANA environments. Environment SAP HANA Cause Inadequate parameter settings can be responsible for various severe issues: Issue SAP Note High memory consumption, OOM 1999997 High CPU consumption 2100040 Bad performance 2000000 Crashes 2177064 Terminations 2399990 Wrong results 2222121 Corruptions 2116157 Consequently it is of high i.. [HANA] Memory Control Memory Control Parameters Global allocation limit Default : 90% of first 64GB of available physical memory + 97% of futher GB Allocationlimit to limit the maximum amount of memory (in MB) that can be allocated individually to processes of a tenant database Statement memory limit 1 GB ~ global allocation limit (in GB) 해당 limit에 도달하면 dump file('compositelimit_oom' 이름으로) 생성 되고 abort됨 --> 시스템에는 영향을 .. [HANA] Timeout관련 파라미터 주요 파라미터 List Parameter Default Unit Dyn. Descriptions global.ini -> [persistence] -> log_backup_timeout_s 900 (15분) s Y Time after which a log backup is performed at latest (SAP doc 1642148) indexserver.ini -> [transaction] -> lock_wait_timeout 1800000 (30분) ms Y Time after which a record or table lock wait is terminated indexserver.ini -> [session] -> idle_connection_timeout 1440 (1Day) min Y T.. [HANA] Savepoint CCH (Consistent Change) Any chanes in persisted page CCH operation은 DB image의 변경을 발생시키는 모든 종류의 database operation 포함 CCH protocol이라 불리는 pre-defined step의 set을 따름 CCH shared lock - data volume의 write access 보장 위해 CCH exclusive lock - 전체 persistence layer에 concurrent write access로부터 보호하기 위해 Consistent System Recovery = recovery 도중에 어떠한 Data의 loss도 없이 복구 하는 것 ---------Data---------------------Log -.. [HANA] Delta Merge 수행 내용 Before Merge Write operation이 Delta1 storage에 발생 Read operaition이 Delta1, Main1에서 발생 During Merge 모든 Write operation이 Delta2로 변경 Uncommited 변경이 Delta 1 → Delta 2로 이동 Main 1의 내용과 Delta 1의 committed 내용이 Merge되어 Main Storage에 저장됨 (Main 2) Read operation 수행 Main 1 Delta 1 (Committed) Delta 2 (Uncommited + New Changes) Main 1과 Delta 1은 Main 2 (Finished compression)로 대체 됨 (짧은 lock 발생) After Merg.. 이전 1 ··· 22 23 24 25 다음
