Re: [EXTERNAL] native i/o and RCAC - performance

Hi Buck

An example, kind of, of what I mentioned, that RCAC is like or actually is a WHERE clause being effected.

Although the doc Alan mentioned does say performance might go down, I think it depends, as all things SQL, on indexes and all. RCAC is used for SQL and RLA but the implementation under the covers does involve optimization, IIRC the explanation I heard when introduced.

Vern

On 5/13/2021 9:09 AM, Buck Calabro wrote:

On Thu, 13 May 2021 at 09:13, Jay Vaughn <jeffersonvaughn@xxxxxxxxx> wrote:

been on a research and testing initiative for months now - many tests.

Without any specifics on the tests, it's only a guess.
Here's a theory that uses exaggeration to spur discussion.

If the 'control' run is a READ that returns every field of a very wide
record (say 1000 fields in a 50 000 byte record), then each transfer
requires moving 50 000 000 bytes.
If the 'variant' run is a READ of those same records, but RCAC
restricts the user to just one field of 1 byte length, then each
transfer requires moving 1 byte.
--buck