Re: Authority required for SQL

YW!

There is little difference now between indexes and keyed LFs, because you can now put selectivity and columns in an index definition - that makes them very similar to LFs.

One of the main differences for me is that SQL knows nothing about multiple members.

I think there used to be a performance advantage for tables or indexes, related to the access path size - but it looks like the *MAX1TB is now available for everything.

Someone else will adjust my answer, of course, if I'm off the beam!

HTH
Vern

On 5/1/2020 11:38 AM, Joe Pluta wrote:

Thanks, Vern!

I definitely have no desire to convert LFs to indexes.  That's actually a show-stopper for now.  But I do want to understand the differences.  I think I can probably play with an interactive debug session as you suggest to test.


On 5/1/2020 11:29 AM, Vernon Hamberg wrote:

Hey Joe

There's no need to convert LFs to indexes, if they have keys that you need, they are just as useful as SQL indexes.

As to whether your SELECT statement will use an LF or index, first STRDBG with no program, then go into STRSQL and run the SELECT.

There will be messages in the job log about which access paths were used, and reasons for why others were not.

Visual Explain will give you more info, but the STRDBG thing is a good start.

In ACS, one of the actions you can use is an SQL performance tool, I think. You can go into that, find your job where you ran the SELECT in STRSQL, and find that statement, then get VE output for it.

HTH
Vern