Livecache data

[Former Member]

Guys,

Looking for few basic doubts about LC data. I searched multiple sites, books but still have this fundamental question on LC data. Probably an LC expert who has firsthand knowledge of LC operation can guide me on this.

How data in livecache gets populated from APO when for the first time LC is becomes operational ? [after LC is up and RFC connection done].

Also as master data and transactional data transfer goes between R/3 and APO multiple times during a day. How often this data from APO gets into LC ? I heard APO DB data and LC data should be in sync else data inconsistency may occur. But to what extent this sync is possible as data structure is different in APO DB and Max db(LC).

Moreover when some planning takes place in LC with COM routines then I guess some changes happen in LC data later how this data goes back to APO DB.

[Former Member]

Hi MikeJ,

Find these links.

Live Catch

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http://help.sap.com/saphelp_nw70/helpdata/en/42/db70ae3f382cede10000000a1553f7/content.htm

https://www.sdn.sap.com/irj/sdn/livecache

Regards,

Pullaiah

[keiji_mishima]

Hi Mike J

Actually APO DB and liveCache do not have completely same data in parallel.

Off course, some of the similler information exist in both DB. But mainly, the usage of both DB are different.

APO DB mainly contains master data like product master, location master, transport lane.

(some table that contains link data beween R/3 and APO exist APO DB and liveCache.

like /SAPAPO/ORDKEY, /SAPAPO/ORDMAP). To access this table data, normal

SQL is used.

liveCache mainly contains transaction data. To access liveCache data, liveCache routin(com routin) is used.

And update process for both DB normally should take place real time. So application program access both table depending on required data.

I guess you consider liveCache as memory DB and APO DB is kind of disk. But actually it is not true.

APO DB is standard DB based on RDMS like Oracle, MSSQL, DB2, or MAXDB. This is just normal DB.

liveCache, it is called memory based DB. But it is more or less DB with huge datacache. So in liveCache ideally most of the data exist in memory space (datachace space) and liveCache also has disk space called data devspace and log devspace. So even liveCache shutdown, data are also stored in disk space (devspace), information is not disappear. Data/log devspace is not APO DB.

APO DB and liveCache are completely different. (In latest release, you can use one MAXDB for APO DB and liveCache. But as I wrote in the beginning, both DB contains different data).

For more better understanding, I recommend you to read following documents.

Both documents are not new, but it contains important basic information.

https://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/72cdbe90-0201-0010-6986-eae36eb6...

https://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/66f7351f-0801-0010-96b4-f91d424b...

If you have question about livecache, I also recommend you to post question in MaxDB/liveCache.

best regards

Keiji