Hi,
I am trying to understand the co-processors concept used by Phoenix.
When i try to explain query: explain select "drugname",count("isr") as count
from DRUG group by "drugname";
+------------+
| PLAN |
+------------+
| CLIENT PARALLEL 1-WAY FULL SCAN OVER DRUGNAME |
| SERVER AGGREGATE INTO ORDERED DISTINCT ROWS BY [drugname] |
| CLIENT MERGE SORT |
+------------+
According to my understanding of co-processors the aggregation and group by
part is handled here by co-processor on the region-server side which hosts the
region for specified table.
But 1st line specifies, scan is at CLIENT. Does it mean entire data comes to
client? If so then how aggregate function is executed on server side? How
different regions on different servers will be scanned parallely?
I have already filed Jira for Explain plan Documentation but it is still
unassigned.
Any help would be appreciated.
Thanks andRegards,
Komal Ravindra Thombare
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