In the nodetool tablestats command, i can see 'number of keys (estimate) '. I know its same as number of partitions ( correct me if i am wrong). Why is it an estimate? If we create a table with primary key with (states, date) with states being partition key. So there wil be total of 50 states ( US) , meaning total 50 partitions. And the rows being under each of these partitions spanning multiple nodes. So how is 'estimate' coming in tablestats - 'Number of keys'?
Also i am in a scenario where i need to calculate the count of rows(estimate only needed) from a big table. I cannot use dsbulk count as of now.
Is there any other fast way just to get the estimate row count? Like using any other tools?