答复: MDAM on index

Thanks all, I want to confirm if all conditions meet, index access can also use MDAM. it is supported and that is great! I believe in practice if all PK and Index still cannot cover the query pattern, it is time to check the design ☺ Thanks, Ming 发件人: Qifan Chen [mailto:qifan.c...@esgyn.com]

Re: MDAM on index

The scan optimizer picks the MDAM scan or subset scan based on the *cost*. For MDAm to win, the low UEC on the leading key columns is a pre-condition. Thanks --Qifan On Mon, Mar 28, 2016 at 10:23 AM, Rohit wrote: > And remember, the key available for MDAM in a secondary

RE: MDAM on index

And remember, the key available for MDAM in a secondary index includes both the secondary index columns followed by the primary key columns, or  c3, c4, c1, c2 in this case.  Same MDAM rules should apply to the secondary index as the clustering index since its a clustering index too.