RE: Creating Logicals before or after populating a file ?

["Raikov, Leonid" <Raikovl1@xxxxxxxxxxxxxxxx>]

It most certainly depends on the type of system you've got. IBM says for
an unconstrained N-way configuration with parallel index build enabled
it's more efficient to populate a physical and then to build access
paths.

If you have not just one, but many large files, my experience shows,
that multiple instances of the 'create physical-create indexes-populate
the file' sequence, submitted for each of the required files is the best
solution.

But you've got to have an unconstrained configuration (i.e. enough
DASD/DASD controllers and main storage). In a constrained configuration
all kinds of side-effects are possible.

Lo 

Email   -       raikovl1@midas-kapiti.com
Phone +44 1753 708 266
Fax     +44 1753 570233

The views and opinions expressed in this e-mail message are the sender's
own and do not necessarily represent the views and opinions of Misys
plc.



> -----Original Message-----
> From: Evan Harris [SMTP:spanner@ihug.co.nz]
> Sent: 15 October 1998 01:09
> To:   midrange-l@midrange.com
> Subject:      Creating Logicals before or after populating a file ?
> 
> 
> We are about to embark on an exercise that will populate a *large*
> database file (40 million records plus). This file has about 20
> logical
> files built over it.
> 
> My question is, which is more efficient:
> 
> 1. Populating the file and building the logicals ?
> 
> 2. Building the logicals and populating the file ?
> 
> Any thoughts would be greatly appreciated.
> 
> Cheers,
> Evan Harris
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