Create a partitioned table using Round Robin

[Former Member]

Hi,

I want to create a partitioned table.

My concern is that if I  use round robin now, whether I can  create a primary key for this table in the future?

Thanks!

[former_member182302 · Accepted solution]

You cannot use Round Robin, if your table has primary keys.

But as you must know , now we can create a HASH Partitioning on the tables with out primary key too, i thought ii would rather test once again and comment:

Please find the screen shot below which confirms that Round Robin cannot be done on table with Primary keys.

Where as the table without primary keys am able to use Round robin. Till here it was fine for me.

Now in the second case where i created a table with Round robin and then later i added the primary key using Alter statement, then am able to have Round Robin on the table with primary keys. ( don't know what does that means )

Column screenshot:

Regards,

Krishna Tangudu

[Former Member · Accepted solution]

Krishna:

You answered my question exactly. Thanks!

BTW, the screenshot for "column screenshot" is corrupted, could you re-post it?   Thanks!

[former_member212303]

Is that a bug? Anyone can answer?

I think HANA views it as a multi-level partitioning and does not throw errors, although a Round-Robin Round-Robin partitioning is of no meaning.

You can also read some info about partition group to have a better understanding of multi-level partitioning.. All parts of a partition group must reside on the same server.

BTW, if I don't get it wrong, the reason why primary key is not allowed in round-robin is that database must cover all partitions for uniqueness check if there was a primary key, and this leads to poor performance.