Relation between HANA and SLT

[Former Member]

We have HANA system which have connect to different schema through SLT.

If we will replicate more than 10 table at a time,so will it effect to HANA system performance .

System performance means will it make any delay to activation of views.

Could you please give us the details related to this .

[former_member183326 · Accepted solution]

Hello,

I would say it would be best to direct this to the SLT SCN?

Here is some information I could gather for you, I hope it helps.

1: Ensure sufficient resources:

Ensure enough resources are available in all the three participating systems (Source, SLT and target).

Resources include:

a) System resource like RAM, CPU, Disk Space

b) Work process/Jobs - In the source system, the number of available dialog work processes that are reserved for the replication should be equal to the no. of data transfer jobs running in SLT. If a lot of tables are selected for load / replication at the same time, it may happen that there are not enough background jobs available to start the load procedure for all tables immediately. In this case, one may increase the number of load job – assuming sufficient system resources are available.

2. Index creation

In case of big tables (>1 GB in size),it is good to create secondary index on the column which have largest number of distinct values. This improves the reading performance significantly. Also, look for the index being used by the logging table. It may sometimes help if reorganization of index is done.

3. Order of logging table index and Read function module

For maximum efficiency in replication, the IUC index of the logging table must have the same field order as the select statement which is reading the data from the logging table of source table. If there is any order mismatch , either drop the IUC index and recreate it or stop replication on table and again add it for replication.

4. Upgrade DMIS component

It is always recommended to upgrade the DMIS to the latest version. One possible cause for latency could be a temporary inconsistency in the logging table.  When an inconsistency occurs in the logging table, records will not get processed until the inconsistent record is once again updated in the source system. The system may be missing many notes actually. Therefore, it is good practice to stay current with correction notes.

5. Advance replication settings

a) Increase jobs for replication - For tables with a large volume of data (especially if they are cluster tables - where the read performance is about 70% compared to transparent tables), one can use the transaction Advanced Replication Settings (transaction IUUC_REPL_CONTENT or LTRS) to further optimize the load and replication procedure for dedicated tables. In the tab page IUUC PERF OPTION/performance options in LTRS, one can assign more jobs to run in parallel for a table or define a sequence that should be considered if load and replication of tables should run subsequently.

b) Change reading type - switch the default reading type 3 to another more appropriate reading procedure.

c) Parallel replication – Use parallel replication to speed up the replication of bigger tables and thereby reducing latency. Steps on how to enable parallel replication is described in detail by Tobias Koebler in his blogs  -

http://scn.sap.com/community/replication-server/blog/2013/10/04/how-to-enable-parallel-replication http://scn.sap.com/community/replication-server/blog/2014/02/25/how-to-filter-on-the-initial-load-pa...

BR

Michael