RE: RE: embedded SQL Precompiler

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: Mike Naughton
>
> I guess a downside, performance-wise, might be the overhead of creating
> the file in the first place -- some of the more adept programmers on the
> list might suggest something fancier using a user space, maybe?

I think it depends on the size of the original select, Mike.  What if the
original SELECT selects, say, five million records out of a 100 million
record file?  Would you really want to create that million record temporary
file?  Sure, it could be done, but I was thinking more along the lines of a
temporary index, that would contain just a list of record numbers back to
the original file.

Of course, the problem there would be concurrence - records could get
updated, thereby dropping them from or adding them to the list.  But you
could either lock the file, or attach a listener, along the lines of the
logical file listeners IBM already has in place.  But your temporary file
idea certainly makes sense, especially for smaller selections.

Joe