Update :- Going by explain plan I created a salted table with 12 buckets. Now the explain plan is following :-       +-------------------------------------------------------------------+----------+ | PLAN | EST_BYTE | +-------------------------------------------------------------------+----------+ | CLIENT 12-CHUNK PARALLEL 12-WAY FULL SCAN OVER GA_3 | null | | SERVER AGGREGATE INTO ORDERED DISTINCT ROWS BY ["ENTITY_ID"] | null | | CLIENT MERGE SORT | null | +-------------------------------------------------------------------+----------+       But response time is still same.   Observed one more thing :- If I don't use sum in my query response is fairly fast.  For example    select ENTITY_ID, SUM(PRODUCT_LIST_VIEWS) from GA_TABLE_2 where SF_ID = '1' group by ENTITY_ID;   this query took 631ms   but    select ENTITY_ID from GA_TABLE_2 where SF_ID = '1' group by ENTITY_ID;   this took only 30 ms.   I'm new to apache phoenix. It would be really helpful if someone can help out.     ... View more