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write-through cache datasets
Posted: Mon May 07, 2012 4:17 pm
by just4u_sharath
what does write-through cache dataset mean? I came across this in IBM book.
Posted: Mon May 07, 2012 8:06 pm
by ray.wurlod
Which book? What is the context? I did not find the term using a search against the
Information Center
Posted: Tue May 08, 2012 8:29 pm
by just4u_sharath
Following is the link to the pdf
http://www.redbooks.ibm.com/redbooks/pdfs/sg247830.pdf
chapter2: topic 2.2.1
Posted: Tue May 08, 2012 8:58 pm
by ray.wurlod
OK, in that scenario "write-through cache" is similar to "staging area". The target Data Set is used as a holding area for data to be loaded into a table that is also being used as a source by the job, to avoid locking issues. Data Sets are ideal for this role because, unlike other mechanisms, they store data in exactly the same format as is used within DataStage - indeed, if you examine the score the operator used to read or write a Data Set is copy (the in-memory data set is simply copied to or from the on-disk structure).