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Database migration to MAXDB for ECC 6.0

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Hi Experts,

I have been in process of testing database migration from oracle to MAXDB(SAPDB). I have exported database of size 900GB by using package and table level splitting method in 12 hr.

Now I am importing into MAXDB. But the import is running very slow.

System is configured with 8CPU. Cache size for DB instance is allocated with 10GB. I have running R3load process with parallel 16 CPU processes. Still import is going slowly with more that 32 hrs.

So cloud some on suggest for performance improvement of this import process.

Please let me know for further information.

Regards

Santosh

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Answers (3)

Answers (3)

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Answered

markus_doehr2
Active Contributor
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> System is configured with 8CPU. Cache size for DB instance is allocated with 10GB. I have running R3load process with parallel 16 CPU processes. Still import is going slowly with more that 32 hrs.

If you don't use specific options your import will be serialized due to the fact, that R3load triggers a savepoint after each table, even empty ones. Use the very latest R3load and libdbsl on the import system.

For that system configuration I'd configure the migration monitor as follows:

-merge_bck -force_repeat -loadprocedure FAST -para_cnt 16

Also increase the value of the database parameter

MaxTempFilesPerIndexCreation

For the time of the import I'd even give the database more memory to keep more data inside, this will increase the time for creating indexes.

Check what the database is doing by executing

x_cons <SID> sh ac 1

Markus

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Hi,

I have tested migration import with parameter setting that you suggested. But Migration is still taking longer than 60 hrs now.

My current setting is

DB cache Size 12G

No of parrallel jobs 16

MAXCPU 8

R3load options -merge_bck -force_repeat -para_cnt 16 -loadprocedure FAST

MaxTempFilesPerIndexCreation 4096

I have splitted all big tables those are bigger than 100 oracle extents in a smaller unit of 20%, 10% and 5% during export.

Could you please suggest further to improve the import process?

Regards

Santosh

markus_doehr2
Active Contributor
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> DB cache Size 12G

> No of parrallel jobs 16

> MAXCPU 8

> R3load options -merge_bck -force_repeat -para_cnt 16 -loadprocedure FAST

> MaxTempFilesPerIndexCreation 4096

I would set "MaxTempFilesPerIndexCreation" to 131072.

The question is: what is taking so long? What's your database doing in all the time?

Did you try to evaluate the times using the time analyzer? (Note 784118 - System Copy Java Tools)

Markus

tomas-krojzl
Active Contributor
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Hello,

check this material from SAP:

then click on "System copy optimization"

?rid=/library/uuid/8091fedf-5346-2a10-e4a0-a3cafe860199

This is perfect document on how to speed up the migration.

I would highligh one fact: If source or target database is MaxDB (your case) - you should be using sorted unload - see Note 954268 - Optimization of export: Unsorted unloading. (Just to eliminate that this is not the problem.)

In case you are not happy with performace I would suggest to review database configuration (especially parameter CACHE_SIZE and MAXCPU).

After the migration you can also review the import process using MigTime tool and maybe adjust the table/package splitting or defining package order (but this is usually problem for export).

If you identify the problem - please come back to share what was the problem and solution.

Best Regards.

Former Member
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You are using too much R3Load processes. Don't setup more R3Load processes than physical CPU cores.

Former Member
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SAP is recommending two parallel processes per CPU, so in fact he is doing correct.

Although it is advisable to perform multiple runs and play with these parameters to find the optimum..

Kind regards,

Mark