Re: perfm of Date\Time\Timestamp

[Barbara Morris <bmorris@xxxxxxxxxx>]

On 2011/7/13 5:25 PM, CRPence wrote:
> ...
> As I recall the Date\Time support in the languages had some performance
> issues due to implementation choices. I recall also that [a couple
> releases] later some changes were made to improve against that original
> implementation [perhaps only in the RPG HLL?]; something to do with
> utilization of external-form [visual presentation formats] versus
> internal-form [integer data] which required conversion from the former
> to the latter before doing calculations, and then the reverse conversion
> [to external form] for writing to the database. The original
> implementation in the database as I understood, was chosen to fit nicer
> with both the interface to and the [original design and] implementation
> of, the HLLs. I believe part of the changes to improve performance may
> have been via exposing database record buffers to an HLL [perhaps only
> RPG updated to take advantage] with date data in internal-form versus
> external-form for read, and similarly enabling the record buffer from
> the HLL to contain internal-form versus external-form for write.

Chuck, the RPG compiler and runtime only work with date data in 
external-form. The runtime uses MI functions to do any calculations 
involving dates, including assignments. I believe those MI functions 
transform to internal form before doing the actual work, and then back 
to external form for the returned value.