Raw reflection not used in basic select *

I have a VDS that is composed of a combination from other VDS.
I’ve created the basic raw reflections, which ran without any issue.

However, this reflection is not used when doing a basic select * from this VDS.
Any way to understand why ? (query profile attached)8667078e-b555-41ca-95d5-857406fb6347.zip (44.7 KB)

Thanks for reporting this. We are always trying to improve our reflection matching code. I will take a closer look at the profile and see if it’s related to some known issues we’ve discovered recently.

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Not sure if this can be linked, but the VDS is using a VDS that has a join with itself.

such as

inner join VDS as VDS2 on VDS1.col1=VDS2.col1
and VDS2.“date” between DATE_SUB(VDS1.“date”,INTERVAL ‘7’ DAY)) and VDS1.“date”

This is for calculating rolling statistics as it seems that it’s not currently possible to do such calculation with Dremio WINDOW functions.

Hope this helps.

Hi @steven, any chance to identify the issue ? I have other examples of aggragegation and raw reflections not used.

I don’t know for sure if this is the case, but it does look similar to some issues that we fixed for 2.1.6. You could try upgrading and see if it has been fixed in your case.

If not, could you rerun the query, but first turn on the verbose profile via the advanced option:


This will provide additional information that might help us figure out the problem.