That depends on the driver you use but separate queries asynchronously around the cluster would be faster.
-- Rahul Singh [email protected] Anant Corporation On Feb 20, 2018, 6:48 PM -0500, Eric Stevens <[email protected]>, wrote: > Someone can correct me if I'm wrong, but I believe if you do a large IN() on > a single partition's cluster keys, all the reads are going to be served from > a single replica. Compared to many concurrent individual equal statements > you can get the performance gain of leaning on several replicas for > parallelism. > > > On Tue, Feb 20, 2018 at 11:43 AM Gareth Collins > > <[email protected]> wrote: > > > Hello, > > > > > > When querying large wide rows for multiple specific values is it > > > better to do separate queries for each value...or do it with one query > > > and an "IN"? I am using Cassandra 2.1.14 > > > > > > I am asking because I had changed my app to use 'IN' queries and it > > > **appears** to be slower rather than faster. I had assumed that the > > > "IN" query should be faster...as I assumed it only needs to go down > > > the read path once (i.e. row cache -> memtable -> key cache -> bloom > > > filter -> index summary -> index -> compaction -> sstable) rather than > > > once for each entry? Or are there some additional caveats that I > > > should be aware of for 'IN' query performance (e.g. ordering of 'IN' > > > query entries, closeness of 'IN' query values in the SSTable etc.)? > > > > > > thanks in advance, > > > Gareth Collins > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [email protected] > > > For additional commands, e-mail: [email protected] > > >
