Re: reorg HUGE file

["David Morris" <dmorris@xxxxxxxxxxxxx>]

Joe,

In some cases you can speed up SQL access with some strategic "extra" 
logicals.  For example: If you have a lot of sql that joins to a customer file 
to retrieve customer name you can save a lot of I/O by creating a logical 
by customer number and name.  This allows the name to be retrieved 
directly from the access path.  Another requirement may be a unique logical 
by customer number.  If you create the number/name logical first and then 
number, you save some resources in addition to speeding up your queries.

David Morris

>>> joepluta@plutabrothers.com 02/27/01 11:22AM >>>
Stupid question, I know, but why have L6, L8 or L2 at all?

---------
Noticing that L6 could use the access path of L8, and L8 could use the access
path of L3, and L2 could use the access path of any of the other listed
logicals, does the system recognize this and build L3 before L8, L8 before L6,
and build L2 last?  (What's the term that describes a logical file using the
access path of another?)  Or do key duplicates follow FIFO by default?  How do
I tell?



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