Reflection refresh is not accelerated if it involves a JOIN

#1

For the below example query, UI (run) will be accelerated but reflection refresh will not be accelerated.
Query profile for UI (run)
a833c381-532a-4013-9b7f-04de1eb12106.zip (38.2 KB)

Query profile for reflection refresh:
82f084d7-68f0-4873-873e-c50cc89533ae.zip (73.4 KB)

Example query:

with subscribers as (
    select user_profile_id
    from "core".subscriptions
)
select * 
from "core".signups
    inner join subscribers on subscribers.user_profile_id = signups.user_profile_id
Raw reflection not used
#2

Hi @joejk,

The reflection refresh does not look like it’s referring to the same VDS as your query (compare the Convert To Rel sections of the query plan and you’ll see they are different).

For the reflection job, can you try running a SELECT * FROM my.vds where my.vds is the VDS for which you’ve built the reflection?

#3

@joejk, I was mistaken; those Convert To Rel may be different depending on whether you are doing and aggregate reflection or a raw reflection. The information I requested would still be useful in diagnosing the issue.

#5

@ben,
I ran into this again with another query. Posting it hoping it is useful. Also, it would be useful if there is any documentation around what Convert to Rel is.

UI(Preview) was accelerated. Here is its profile
6ac0d31c-2468-47b5-89e2-32dda1a5fc04.zip (52.4 KB)

Raw reflection was not accelerated. Here is the profile
67d6c83b-be5a-4d53-9e0c-36eaf8d2ef42.zip (65.7 KB)