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Posted by: Bob Cozzi
Rogue Programmer
Cozzi Productions, Inc.
Performance of the Rreadn (rec I/O) API
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Published: 01 May 2013
Revised: 02 May 2013 - 3614 days ago
Last viewed on: 24 Mar 2023 (4517 views) 

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Performance of the Rreadn (rec I/O) API Published by: Bob Cozzi on 01 May 2013 view comments(2)

I had to move from standard RPG IV I/O (CHAIN, READ, SETLL...) to using the _ROpen, _RReadn and _RLocate functions in my Copy to CSV routine.

What I'm noticing now is that the time it takes to convert a LARGE database file to CSV has increased substantially over native RPG I/O methods.

Does anyone have any performance tips, documents or webpage(s) that might help improving performance when processing tens of thousands of records with the _Rxxxx I/O APIs.

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Posted by: KevinLandWaster
Premium member *
Sydney, NSW, Australia
Comment on: Performance of the Rreadn (rec I/O) API
Posted: 9 years 10 months 24 days 4 hours 52 minutes ago
Edited: Wed, 01 May, 2013 at 17:23:46 (3615 days ago)

Hi Bob,

Two things: blocking when you _ROpen, and also not having a separate buffer - using the inbuilt buffer & then setting a pointer to your record structure to the inbuilt buffer. The latter is documented in TFM somewhere. (Library functions where _Rxxx are documented or maybe C programmer's guide).



Posted by: bobcozzi
Site Admin ****
Comment on: Performance of the Rreadn (rec I/O) API
Posted: 9 years 10 months 23 days 8 hours 22 minutes ago

Thanks Kevin. I'm doing those two things and it hasn't helped. I'm going to play with the SEQONLY and NBRRCDS parameters of the OVRDBF command to see if it helps.