Set Up SAP HANA System Replication with the SAP HANA

HANA System Replication is one of the important topic in SAP HANA. Being used in the context of high availability and disaster recovery scenario, It is really important to learn how to setup HANA System Replication in multi-tier replication scenario.   In this scenario we are enabling HANA System Replication – In Multi-tier scenario.   There are 3 HANA nodes: A, B and C, named SiteA, SiteB and SiteC Site A : Primary Database Node Site B: Secondary Database Node / HA Node Site C: DR node Replication Mode: From Site A –> Site B : SYNC From Site B ……

Replication Modes between Sites : HANA Replication

Here i am explaining different replication Modes between Sites in the HANA Replication setup. Synchronous (SYNC) : The secondary system sends an acknowledgment back to the primary system as soon as the data is received and persisted to the log volumes on disk. Asynchronous (ASYNC): Asynchronous replication, the primary does not wait until the secondary sends an acknowledgement. Synchronous in-memory (SYNCMEM):The secondary system sends an acknowledgment back to the primary system as soon as the data is received in memory. The disk I/O speed on the secondary system doesn’t influence the primary’s performance. Site Distance  Replication Mode  < 100 KM SYNC ……

statement_memory_limit

Parameter : statement_memory_limit Key Highlights :   statement_memory_limit parameter is used to control memory limit for single query execution. Sometime it happens if we don’t set any limit on query level then single execution of query takes complete HANA memory and result to the HANA crash . So it is really improvement to set proper value of statement_memory_limit   Description in detail: Sets a statement memory limit on HANA node  in GB (0 or not set = disabled) The limit defines the maximum memory that can be temporarily used for the execution of a statement on one node. When a statement execution  ……

memorymanager –> Parameter : allocationlimit

Parameter : allocationlimit  Key Highlights : This parameter is very useful in the Multi-tenant database container (MDC) system to set memory limit on each tenant system. Example : If we have 4 tenant systems in the landscape then we can set on indexsever.ini file –> allocationlimit for each tenant system to the accepted memory limit for each tenant system. Parameter: allocationlimit Description: Sets an upper limit of memory usable by individual processes in megabytes. When set to 0 or missing, the SAP HANA system implicitly calculates a default value based on global_allocation_limit. Multi-tenant database container (MDC) systems: In a tenant database, the parameter ……

inifile_checker –> Parameter : interval

Parameter: interval   Description: Sets a time interval in seconds between two checks for differences of ini file parameters between primary and secondary systems in a system replication scenario. To disable/enable those checks, set the parameter [inifile_checker] enable. Value: Positive integer   Default: 3600 (seconds = 1 hour)   Restart required: No     Ref: SAP HANA Admin Guide and Frequently Used Configuration Parameters in SAP HANA

inifile_checker–> exclusion_[|*][/]

Key Highlights: This parameter will help in the scenario where we don’t want to replicate few parameter from primary to secondary site. Scenario where we want to have different value of particular parameters in primary and secondary site. This parameter is helpful where replication on the primary site with [inifile_checker]/replicate = true is enables With parameter replication activated, any changes made on the primary are automatically replicated to the secondary sites; without this parameter replication activated changes should be manually duplicated on the other system.   Parameter: exclusion_[<inifilename>|*][/<LAYER>] Description: The ini file name can be replaced with an asterisk. The LAYER ……

[inifile_checker]/enable=true & [inifile_checker]/replicate = true

  inifile_checker –> enable = True  &  [inifile_checker]/replicate = true Key Highlights : [inifile_checker]/replicate = true- This parameter is very useful in the scenario where we have muli -tier and multi-target replication setup in the landscape . If we are changing any parameter in the primary site and [inifile_checker]/replicate = true- parameter is enabled then automatically it will be reflected in the secondary site . It helps to sync-up the parameters across all the HANA sites . If we don’t have [inifile_checker]/replicate = true : parameters set on HANA then there are chances that if we are changing any parameter in the primary site then ……

Hana table partitioning | re-partitioning | Improve Performance

Hana table partitioning is one of major problems for most of the customers to re partition of HANA tables due to the reason that a table partition cannot contain more than 2,147,483,648 (2 billion) rows. During the time customer need to perform table re partitioning due to 2 billion limit and For large tables – table partitioning takes lot of time and customer wants to optimize overall run-time of table partitioning . Here i am providing tips to improve total run-time of Hana table partitioning along with table partitioning steps: Run delta merge on table before re-partitioning . Command for delta merge “MERGE ……

EHP8 Upgrade Error ‘SPDA_DISASSEMBLE_QUEUE’ EHP_INCLUSION Phase

Issue: During EHP8 upgrade ,we faced issue during SPDA_DISASSEMBLE_QUEUE step of  EHP_INCLUSION Phase. 4 ETQ399 … ERROR in patch queue handling 1 ETQ124 Scanned file ‘log/SPDA_EHP_INCLUSION.LOG’ from offset 548255 to 846628 for errors. 1EETQ399 Last error code set is: RFC system SID nr 00 function ‘SPDA_DISASSEMBLE_QUEUE’ 1EETQ399XRFC failed with code 1 key RFC_COMMUNICATION_FAILURE: 1EETQ399Xconnection closed without message (CM_NO_DATA_RECEIVED) 1EETQ399XIf you put new packages in the download directory, use option ‘init’ to upload them 1EETQ204 Upgrade phase “EHP_INCLUSION” aborted with severe errors (“20190807115630”)   Solution: Not able to get any clue from SUM log files .It was giving same error logs highlighted ……

How to Fix “Start of UME Service Failed” in JAVA System

Issue: If your Java system server nodes are not coming up and in the server log files you see similar entries as below . Aug 2, 2019 12:22:39 PM com.sap.security.core.persistence [SAPEngine_System_Thread[impl:5]_125] Fatal: Initialization of ABAP data source (com.sap.security.core.persistence.datasource.imp.R3Persistence) failed: “Name or password is incorrect (repeat logon)”. This message is critical if it appears during the startup of the AS Java. Aug 2, 2019 12:22:39 PM …re.server.ume.service.UMEServiceFrame [SAPEngine_System_Thread[impl:5]_125] Fatal: service com.sap.security.core.ume.service ================= ERROR ================= Core service com.sap.security.core.ume.service failed. J2EE Engine cannot be started. com.sap.engine.frame.ServiceException: Start of UME service failed. Check help topic “Start of UME Service Failed”. Technical details: Name or ……