Why is Hashed File data changing randomly

Pathy · Post by **Pathy** » Tue May 19, 2009 2:38 am

Hi friends,
Iam facing an issue in the hash file for one particular column. The column length is 1000. As the data is too big, each time when retrieved from the table and loaded to the hashfile, the data in the column is rearranged randomly.

Say my data is Energy systems / technology, Industrial wastewater treatment. ....etc.,

It stores as Industrial wastewater , Energy systems / technology, .etc., in the hash file .

This creates an issue while am trying to do SCD process, as each time am running the scd job it is going to the update link even if the source data remains unchanged.

So is there any way to keep the data unchanged,can any one help me out?

Thanks in advance

chulett · Post by **chulett** » Tue May 19, 2009 5:35 am

First off, it is a hashed file, not hash file or hashfile.

Secondly, I don't see how one could ever 'rearrange data randomly'. Something else must be going on. Can you provide more details as to the design of your hashed file and exactly how you populate it? For example, is this field a Key field or a non-key field? Are you just moving a single data field to the hashed file's field or is this string 'built' somehow? When you read the hashed file, are you using the exact same metadata to read it that was used to write it?

Etc. As many details as you can stand to document for us, please.

ray.wurlod · Post by **ray.wurlod** » Tue May 19, 2009 3:56 pm

I suspect you have these strings (separated by / in your example) as separate fields in the hashed file. Fields in hashed files are accessed by ordinal number, not by name, so your metadata in the link where you are writing to the hashed file does not correspond to the metadata in the link where you're reading from the hashed file. Get these the same and you will have eliminated the "random re-organization" - which isn't really random at all.

Pathy · Post by **Pathy** » Wed May 20, 2009 5:40 am

thanks for ur reply.

Yes its a non-key field in the hashed file,then single data field to the hashed file's field and not a derived one.The metadata is the same.

iam really wondering how the data in the singlecolumn gets randomly changed,if the table is having the data as "Industrial wastewater , Energy systems / technology, X-Ray Diffraction, Nickel Compounds" for a column say Name_3 ,the hash file is loaded with "Energy systems / technology, Industrial wastewater treatment X-Ray Diffraction, Nickel Compounds,Industrial wastewater ".

So the hashedfile and table data is not matching and hence my records are always passing to the update link.

chulett · Post by **chulett** » Wed May 20, 2009 6:29 am

It's not getting changed. What is your key in the hashed file? How unique is it? You are aware of the 'destructive overwrite', last-one-in-wins way they work, yes?