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From cesare cugnasco <cesare.cugna...@gmail.com>
Subject Huge query Cassandra limits
Date Tue, 16 Jul 2013 11:46:42 GMT
Hi everybody,

We  are working on porting some life science applications to Cassandra, but
we have to deal with its limits managing huge queries. Our queries are
usually multiget_slice ones: many rows with many columns each.

We have seen system start to slower until the entry point node crashes when
increasing the amount of rows and columns required in a single query .

Where does this limit come from?

Giving a fast look to the code seems like the entry point is stressed
because it has to keep all the responses in memory. Only after it has
received all the responses, from the nodes, Then, it resolves the conflicts
between different versions and sends them to the client.

Would not be possible to start sending the response to the client before
receiving all them? For instance, it may speed up the  Consistency level
ONE queries.

Does anyone worked on it? Is it the real reason of the decreasing of
performances?


Thank you,

Cesare Cugnasco

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