cache

[Former Member]

BEx Gurus

to increase the query performance instead of using precalculated web templet we were suggested to use BLOB(Binary Large Objects)transparent CACHE.

can you please help me out by giving information about BLOB CACHE.

like what are the advantages and disadvatages over precalculated templets and the settings.

i gone through few documents and forums and once such information on this is

"Best Practice store CACHE in BLOB table/cluster table/flat file so that ALL Application servers can UTILIZE it.

In these way USER running query from ALL/ANY Aplication server will be directly UTILIZING CACHE and faster the performance.

In these way you are not disturbing any SETTINGS . "

my question is

in cache parameters we have the option of changing the persistant mode to Transparant table (BLOB). in addition to this change do we need to change anything in cache mode in RSRT(what we have here is main memory without swaping).

how do u know that my query is getting data from cache memory or from cube(any transaction code.

and if i change the persistant mode to Transparant table (BLOB) then when the query runs will all the application servers (if we have different application servers) pick up result from these tables. if so do we have to make any settings??

help require guys

thanks in advance

[Former Member]

There are a couple good resources on Global cache on SDN. Here's a couple links

<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/ef0e1d95-0501-0010-b0b3-aed7be1da554">OLAP Cache - Transcript</a>

<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/9f4a452b-0301-0010-8ca6-ef25a095834a">How to Perform Tuning with the OLAP Cache</a>

<i>in cache parameters we have the option of changing the persistant mode to Transparant table (BLOB). in addition to this change do we need to change anything in cache mode in RSRT(what we have here is main memory without swaping). </i>

If you choose a Persistent Mode of BLOB, your Cache Mode would be 3 o r 4 - Persistent Cache per Appl Server or Across Appl Servers. Depending on the SP you're at, some of this screen changes at BW 3.5 SP 18, when I choose Cache Mode of Main Memory, the Persistence Mode option disappears. Persisten and in Main Memory are mutually exclusive.

<i>how do u know that my query is getting data from cache memory or from cube(any transaction code.</i>

Couple of options - again depending on BW Version and SP. On my version, ST03N has an OLAP Cache option on the top of the screen. I can then see which quereis are using cache, hoe many navigations, etc. If you get an Early Watch report, that should provide a % of navigations that used cache, e.g. 35% used cache. Table RSDDSTAT entries that show no DB time or DB selects indicate that that navigation used OLAP cache - since it never had to read from the DB. I've never looked, but I'll bet some of the technical content quereis might let you identify navigations that used cache.

<i>and if i change the persistant mode to Transparant table (BLOB) then when the query runs will all the application servers (if we have different application servers) pick up result from these tables. if so do we have to make any settings??</i>

Cache Mode 4 - Store Across Appl servers. otherwise it only gets cached on the server it the user runs the query on.

[Former Member]

Hi All,

I have the same questions.

Any ideas are appreciated.

Thanks,

Pradeep