Unicode export:Table-splitting and package splitting

Question

Hi SAP experts,
I know there are lot of forums related to this topic, but I have some new questions and hence posting a new thread.
We are in the process of doing unicode conversion in our landscape(CRM 7.0 system based on NW 7.01) and we are running on AIX 6.1 and DB2 9.5. The database size is around 1.5 TB and hence, we want to go in for optimization for export and import in order to reduce the downtime.As a part of the process, we have tried to do table-splitting and parallel export-import to reduce the downtime.
However, we are having some doubts whether this table-splitting has actually worked in our scenario,as the export has exeucted for nearly 28 hours.
The steps followed by us :
1.) Doing the export preparation using SAPINST
2.) Doing table splitting preparation, by creating a table input file having entries in the format <tablename>%<No.of splits>.Also, we have used the latest R3ta file and the dbdb6slib.o(belonging to version 7.20 even though our system is on 7.01) using SAPINST.
3.) Starting with the export using SAPINST.
some observations and questions:
1.) After completion of tablesplitting preparation, there were .WHR files that were generated for each of the tables in DATA directory of export location. However, how many .WHR files should be created and on what basis are they created?
2.) I will take an example of a table PRCD_CLUST(cluster table) in our environment, which we had split. We had 29 *.WHR files that were created for this particular table. The number of splits given for this table was 36 and the table size is around 72 GB.Also, we noticed that the first 28 .WHR files for this table, had lots of records but the last 29th .WHR file, had only 1 record. But we also noticed that, the packages/splits for the 1st 28 splits were created quite fast but the last one,29th one took a long time(serveral hours) to get completed.Also,lots of packages were generated(around 56) of size 1 GB each for this 29th split. Also, there was only one R3load which was running for this 29th split, and was generating packages one by one.
3.) Also,Our question here is that is there any thumb rule for deciding on the number of splits for a table.Also, during the export, are there any things that need to be specified, while giving the inputs when we use table splitting,in the screen?
4.) Also, what exactly is the difference between table-splitting and package-splitting? Are they both effective together?
If you have any questions and or need any clarifications and further inputs, please let me know.
It would be great, if we could get any insights on this whole procedure, as we know a lot of things are taken care by SAPINST itself in the background, but we just want to be certain that we have done the right thing and this is the way it should work.
Regards,
Santosh Bhat

Answer 1

Hi,
First of all please ignore my very first response ... i have accidentally posted a response to some other thread...sorry for that 
Now coming you your questions...
> 1.) Can package splitting and table-splitting be used together? If yes or no, what exactly is the procedure to be followed. As I observed that, the packages also have entries of the tables that we decided to split. So, does package splitting or table-splitting override the other, and only one of the two can be effective at a time?
Package splitting and table splitting works together, because both serve a different purpose
My way of doing is ...
When i do package split i choose packageLimit 1000 and also split out the tables (which i selected for table split)  into seperate package (one package per table). I do it because that helps me to track those table.
Once the above is done i follow it up with the R3ta and wheresplitter for those tables.
Followed by manual migration monitor to do export/import , as mentioned in the previous reply above you need to ensure you sequenced you package properly ... large tables are exported first , use sections in the package list file , etc
> 2.) If you are well versed with table splitting procedure, could you describe maybe in brief the exact procedure?
Well i would say run R3ta (it will create multiple select queries) followed by wheresplitter (which will just split each of the select into multiple WHR files)  ...  
Best would go thought some document on table spliting and let me know if you have specific query. Dont miss the role of hints file.
> 3.) Also, I have mentioned about the version of R3ta and library file in my original post. Is this likely to be an issue?Also, is there a thumb rule to decide on the no.of splits for a table.
Rule is use executable of the kernel version supported by your system version. I am not well versed with 7.01 and 7.2 support ... to give you an example i should not use 700 R3ta on 640 system , although it works.
>1.) After completion of tablesplitting preparation, there were .WHR files that were generated for each of the tables in DATA directory of export location. However, how many .WHR files should be created and on what basis are they created?
If you ask for 10 split .... you will get 10 splits or in some case 11 also, the reason might be the field it is using to split the table (the where clause). But not 100% sure about it.
> 2) I will take an example of a table PRCD_CLUST(cluster table) in our environment, which we had split. We had 29 *.WHR files that were created for this particular table. The number of splits given for this table was 36 and the table size is around 72 GB.Also, we noticed that the first 28 .WHR files for this table, had lots of records but the last 29th .WHR file, had only 1 record. But we also noticed that, the packages/splits for the 1st 28 splits were created quite fast but the last one,29th one took a long time(serveral hours) to get completed.Also,lots of packages were generated(around 56) of size 1 GB each for this 29th plit. Also, there was only one R3load which was running for this 29th split, and was generating packages one by one.
Not sure why you got 29 split when you asked for 36, one reason might be the field (key) used for split didn't have more than 28 unique records. I dont know how is PRCD_CLUST  split , you need to check the hints file for "key". One example can be suppose my table is split using company code, i have 10 company codes so even if i ask for 20 splits i will get only 10 splits (WHR's).
Yes the 29th file will always have less records, if you open the 29th WHR you will see that it has the "greater than clause". The 1st and the last WHR file has the "less than" and "greater than" clause , kind of a safety which allows you to prepare for the split even before you have downtime has started. This 2 WHR's ensures  that no record gets missed, though you might have prepared your WHR files week before the actual migration.
> 3) Also,Our question here is that is there any thumb rule for deciding on the number of splits for a table.Also, during the export, are there any things that need to be specified, while giving the inputs when we use table splitting,in the screen?
Not aware any thumb rule. First iteration you might choose something like 10 for 50 GB , 20 for 100 GB. If any of the tables overshoots the window. They you can give a try by  increase or decrease the number of splits for the table. For me couple of times the total export/import  time have improved by reducing the splits of some tables (i suppose i was oversplitting those tables).
Regards,
Neel
Edited by: Neelabha Banerjee on Nov 30, 2011 11:12 PM