Associator Blocksize under v5.1.1

Does anyone know the optimal blocksize for the Associator container in Adabas 5.1.1 under Windows. We have been using 5k but I notice when defining a new database, 2 associators come up as the default - the first defaults to 4k and the second defaults to 32k.

Additionally, when the “auto expand” option is switched on, Adabas creates its own container of 8k.

We are currently using 15,000 rpm drives but are in the process of switching to 10,000 rpm optic drives.

Garry - What is the answer to your question? 4k, 8k, or 32k?

I think it’s very difficult and time consuming to do such performance tests in a proper way. But of course the result would be very interesting.

BTW: The Adabas-documentation doesn’t say much about this issue…

Please note that Adabas srtarting with v5.1 distinguishes between small index blocks (blocksize <16>= 16 KB). Small index blocks are used for small descriptor values (<253> 253 bytes), for example collation descriptors or large superdescriptors. For normal descriptors only small index blocks are used; it doesn’t help you to assign large index blocks for a file - they are not used.

Generally we recommend to use only block sizes of 4, 8, 16 or 32 KB for the database, but we have not investigated if there are really performance differences.

Thanks for the response. I guess the only solution is to set up a test for myself sometime.

With the very large size of the databases we have the blocksize could have a significant impact on performance. Unfortunately it will take a considerable effort to set up and test.