I am seeing some inconsistency (my perception) in the system tables available through the adminstrator/System Information tab.
First off - my interest solely lies in quantifying (at a table level) the amount of memory usage. I know this depeneds on whether the table is loaded into memory or not, and I would assume that some of these system tables also account for that.
On to the details...
When we query this table via "System Information", I see the following
This would leave one to believe that we are looking at a roughly 419GB (converted) memory consumption by the Column Store Tables.
Now, when we use the "Used Memory By Tables" System Information View, I can see this.
This would indicate that Used Memory for ALL column tables is roughly 362GB (converted from MB).
A third reconciliation point is just querying the view "SYS"."M_CS_TABLES"
SELECT SUM(ROUND("MEMORY_SIZE_IN_TOTAL"/1024/1024,4)) AS "MEMORY (MB)"
FROM "SYS"."M_CS_TABLES"
ORDER BY "MEMORY (MB)" DESC
With this, we get a result like this, which seems to correlate with the second example from System Information (and is probably sourced from the same tables/views).
So question here is - what is more accurate? Is the M_CS_TABLES view the right place to get concrete memory usage at a table level? If so, why does the SERVICE_COMPONENT query differ so greatly? Is there additional overheard/management for column store tables outside of the delta merge (delta size is included in "MEMORY_SIZE_IN_TOTAL" from M_CS_TABLES)?
Regards,
Justin