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64 bit HASH files

Posted: Tue Oct 19, 2004 2:50 am
by denzilsyb
Hi guys

I went through the following 2 processes:

for SOLARIS (64bit OS):
  • change uvconfig file parameter from 64BIT_FILES 0 to 64BIT_FILES 1
    stopped DS services
    started DS services
Is DS going to automatically create 64 bit HASH files from now on?

I did exactly the same for my windows 2000 professional on my desktop - a 32 bit machine. I created a job that writes to a HASH file and there were no warnings, no fatals - just a finished-OK run.

If the creation of 64 bit hash files is automatic after following the above process, then I would expect DS on windows to complain about some sort of invalid parameter. I can only conclude then that DS does not automatically create 64 bit HASH files - based on the "ONLY valid on 64-bit capable platforms" in the uvconfig file. It would mean then that for every HASH file we require that is larger than 32 bit allows, we need to create the 64 bit HASH manually.

Or is there a better way?

Posted: Tue Oct 19, 2004 7:05 am
by Thomas.Nel
Howzit DenzilSyb,

Firstly, it is not a good idea to change your uvconfig parameter BECAUSE that will cause all new hash files to be created as 64 bit which is probably not what you want.

There is a better way - you can create a standard (32 bit) hash files and then resize it to 64 bit:

RESIZE filename * * * 64BIT [ USING pathname ]

If you search the forum you will find some useful info.

Tom.

Posted: Tue Oct 19, 2004 7:41 am
by denzilsyb
Hi Tom

I will take your suggestion and play with the concept. Is there a major decrease in performance when using 64 bit HASH files?

Posted: Tue Oct 19, 2004 3:44 pm
by ray.wurlod
The only 64-bit things that get created are the internal pointers within the hashed file. Therefore, it is possible to create them even on a 32-bit operating system. They break when they hit 2GB, not because of anything in DataStage, but because the operating system can't handle files of that size.

I think the wording is that they're "not supported" on these operating systems. Not that they can't be created.

Therefore the answer to your question "Is DS going to automatically create 64 bit HASH files from now on?" is Yes.

You don't really want this, there is a performance hit. Although it's not major, it's definitely there.