Data movement from R/3 DB to APO DB and to Live cache

Question

Dear APO Experts,
I have few questions on live cache and how it works, I understand that Live cache is memory resident database. below are my questions.
1) What sought of data move from R/3 DB to APO DB and then to Live cache DB
2) When data moves from APO DB to Live cache, till how much duration that data stays in live cache
3) And how does data gets pulled in to live cache from APO DB
4) Why do we require live cache logs while data never gets commited to hard disk
5) Do we ever add a datafile to Live cache DB
any info that you provide on this will be really helpfull to me
Thanks,
Chetan

Answer 1

Hello Chetan,
As you know, itu2019s MAXDB/liveCache forum.
What is the version of your system?
The is documentation available at:
   SAP liveCache technology
< Please review document u201CWhat is SAP liveCache technology?u201D >
Sap documents at service.sap.com/scm -> Technology:
u201CliveCache overviewu201D and u201CIntegration overviewu201D
For SAP liveCache documentation also see the SAP note 767598.
Go to SAP link Best Practices for Solution Management: mySAP SCM at   SAP liveCache technology ...
And Review the document u201CManage APO Core Interface in SAP APO (3.x) / mySAP SCM (4.x/ 5.0)u201D
1. As you saw in the reference documents the data transferred from the connected R/3 system to APO.
And the transactional data could be uploaded to the liveCache, if you downloaded them
to the APO database cluster tables first. This procedure steps are running during the
system upgrade < for example, from SCM 5.0 to SCM 7.0 ) u2013 report /SAPAPO/OM_LC_UPGRADE_70 steps. Or you want to migrate the          
liveCache to another operating system or convert your system to Unicode,  
and therefore you want to back up the liveCache data first so that you    
can reload it into the liveCache afterwards - SAP Note No. 632357.                              
2. Could you collaborate more on this sentence. Could you give examples?
3.  u201CAnd how does data gets pulled in to live cache from APO DBu201D
    The data are not pulled from the APO DB to liveCache.
     When you changed the APO data on the system the LCA procedures have been called from ABAP. The objects stored in the class containers in liveCache can be accessed and manipulated only via LCA routines. The registration of the LCA routines is done automatically when the liveCache is started by the LC10. The LCA procedures in the LiveCache are written in C++                          
and shipped to the customers as binary LCA libraries(LCA build) together with the LiveCache.
< See more details in SAP Note No. 824489 or 1278897 as of SCM 7.0 >
4. See the SAP notes:
               869267     FAQ: SAP MaxDB LOG area
             1377148     FAQ: SAP MaxDB backup/recovery
5. You could run the quicksizer & estimate how much data you are planning to have in liveCache.
     Also the amount of data could be increased by the creation of the new data in APO by users
     Or another reason u2026
     In general you will add the datavolume to solve or prevent the DB_FULL issue,
     See u201C17. What do I do if the data area is full? u201C in SAP note 846890.
Thank you and best regards, Natalia Khlopina