To look at the read capacity consumption of a range query, we use the following example table which is using on-demand capacity mode.
pk1 | pk2 | pk3 | ck1 | ck2 | ck3 | value -----+-----+-----+-----+-----+-----+------- a | b | 1 | a | b | 50 | <any value that results in a row size larger than 4KB> a | b | 1 | a | b | 60 | value_1 a | b | 1 | a | b | 70 | <any value that results in a row size larger than 4KB>
Now run the following query on this table.
SELECT * FROM amazon_keyspaces.example_table_1 WHERE pk1='a' AND pk2='b' AND pk3=1 AND ck1='a' AND ck2='b' AND ck3 > 50 AND ck3 < 70;You receive the following result set from the query and the read operation performed by Amazon Keyspaces consumes 2 RRUs in
LOCAL_QUORUM consistency mode.
pk1 | pk2 | pk3 | ck1 | ck2 | ck3 | value -----+-----+-----+-----+-----+-----+------- a | b | 1 | a | b | 60 | value_1
Amazon Keyspaces consumes 2 RRUs to evaluate the rows with the values ck3=60 and ck3=70 to process the query.
However, Amazon Keyspaces only returns the row where the WHERE condition specified in the query is true, which is the row with
value ck3=60. To evaluate the range specified
in the query, Amazon Keyspaces reads the row matching the upper bound of the range, in this case ck3 = 70,
but doesn’t return that row in the result. The read capacity consumption is based on the data read when processing the query, not
on the data returned.
