RE: SQL Performance issues questions

I think a view is simply a helper that doesn't actually affect performance. Have you tried running VE in iNav or iACS?



-----Original Message-----
From: a4g atl [mailto:a4ginatl2@xxxxxxxxx]
Sent: Thursday, November 30, 2017 8:43 AM
To: midrange-l@xxxxxxxxxxxx
Subject: SQL Performance issues questions

I have a few programs that are retrieving data from files with approximately 5 to 750 million records.

The program is executing in approximately 15 seconds which in itself is not bad. However, I would like to improve the performance by processing less records.

A logical file may provide better performance but I would not like to use a logical. I have a simple SELECT with JOIN retrieving the data.

I am considering using a VIEW but am wondering if a VIEW would provide better performance from the point of view that a logical builds a permanent index filtering the records required.

I have run PRTSQLINF and the programs are using existing logicals and is not making any suggestions.

My question is, does a VIEW create a similar retrieval in that it will only read the records in the filter or does it do the filtering at the time the SELECT is executed hence possibly reading all 750 million records therefor not gaining anything?

TIA
Darryl Freinkel