Partitioning on PSA and ODS Change Log

[Former Member]

Who can explaim me how does BW controls the partitioning on PSA and ODS Change Log ? I Have DB2/OS390, with parameters configured on table RSADMIN: DB2_PSA_NUM_Partitions and DB2_PSA_PARTS_PER_BLOCK.

I can not understand the values on tables RSTSODS and RSTSODSPART for these tables. And also the values of partitioning on SE14 -> Storage parameters.

Thanks a lot

Message was edited by: Martha Soares

[Former Member]

I have the same problem:

I have same PSA Table to partition and I have just modified RSADMIN Tables with entries

DB2_PSA_NUM_PARTITIONS= 100 and

DB2_PSA_PARTS_PER_BLOCK= 6 and using transaction transaction RSCUSTV6 have set Partition to 1.000.000.

At this point I have same tables whith mora milions of records, what I have to do to activate the partitioning for the existing tables

Best regards

Augusto Zecca

[Former Member]

Hi Martha,

What happened to the issue. do you have any updates??

sudhir.

[Former Member]

Please find below info about PSA partitioning. I found this piece of info one of the documents that I have on my computer, I’m sure it is somewhere in SDN website. Document title “Performance Tuning for SAP BW”

<b>PSA Partition Size</b>

PSA tables are partitioned (if available in the DBMS) automatically. In transaction RSCUSTV6 the size of each PSA partition can be defined. This size defines the number of records that must be exceeded to create a new PSA partition. One request is contained in one partition, even if its size exceeds the user-defined PSA size; several packages can be stored within one partition.

The PSA is partitioned to enable fast deletion (DDL statement DROP PARTITION). Packages are not deleted physically until all packages in the same partition can be deleted.

Set the PSA partition size according to the expected package sizes. If you expect many small packages, set the partition size to a rather small value, so that these partitions can be deleted quickly.

For DB2/390, see SAPnote 485878 (DB2/390: BW: Partitioning the PSA tables) for more details.

[Former Member]

Thanks a lot.

I have this documents. And I applyied note 485878. That is why I have parameters configured on table RSADMIN: DB2_PSA_NUM_Partitions and DB2_PSA_PARTS_PER_BLOCK.

During a data load, it is not clear how BW system uses, or decides for the partitions. On initial data load it decides just por partition 1. I almost exceeded the limit of DB2 on one partition (64Gigabytes). On delta loads it uses the other partitions, I don know how! I efectivelly do not use PSA, but as the ODS change log is like a PSA table, I have to partition because it will have almost 500 milion records ! Ops, it is very big!!Tables RSTSODS and RSTSODSPART have controls that I can not understand. Because one program that was executed many times decided to cancel when reading these controls. I have an open customer message. May be will have a correction.

Thanks a lot again

Martha