THERE ARE NO JOINS WITH CASSANDRA CQL != SQL
Same for aggregation, subqueries, etc. And effectively multitable transactions are out. If you have simple single-table queries and updates, or can convert the app to do so, then you're in business. On Tue, Mar 13, 2018 at 5:02 AM, Rahul Singh <rahul.xavier.si...@gmail.com> wrote: > Oliver, > > > Here’s the criteria I have for you: > > 1. Do you need massive concurrency on reads and writes ? > > If not you can replicate MySQL using master slave. Or consider Galera - > Maria DB master master. I’ve not used it but then again doesn’t mean that > it doesn’t work. If you have time to experiment , please do a comparison > with Galera vs. Cassandra. ;) > > 2. Do you plan on doing both OLTP and OLAP on the same data? > > Cassandra can replicate data to different Datacenters so you can > concurrently do heavy read and write on one Logical Datacenter and > simultaneously have another Logical Datacenter for analytics. > > 3. Do you have a ridiculously strict SLA to maintain? And does it need to > be global? > > If you don’t need to be up and running all the time and don’t need a > global platform, don’t bother using Cassandra. > > Exporting a relational schema and importing into Cassandra will be a box > of hurt. In my professional (the type of experience that comes from people > paying me to make judgments, decisions ) experience with Cassandra, the > biggest mistake is people thinking that since CQL is similar to SQL that it > is just like SQL. It’s not. The keys and literally “no relationships” mean > that all the tables should be “Report tables” or “direct object tables.” > That being said if you don’t do a lot of joins and arbitrary selects on any > field, Cassandra can help achieve massive scale. > > The statement that “Cassandra is going to die in a few time” is the same > thing people said about Java and .NET. They are still here decades later. > Cassandra has achieved critical mass. So much that a company made a C++ > version of it and Microsoft supports a global Database as a service version > of it called Cosmos, not to mention that DataStax supports huge global > brands on a commercial build of it. It’s not going anywhere. > > > -- > Rahul Singh > rahul.si...@anant.us > > Anant Corporation > > On Mar 12, 2018, 3:58 PM -0400, Oliver Ruebenacker <cur...@gmail.com>, > wrote: > > > Hello, > > We have a project currently using MySQL single-node with 5-6TB of data > and some performance issues, and we plan to add data up to a total size of > maybe 25-30TB. > > We are thinking of migrating to Cassandra. I have been trying to find > benchmarks or other guidelines to compare MySQL and Cassandra, but most of > them seem to be five years old or older. > > Is there some good more recent material? > > Thanks! > > Best, Oliver > > -- > Oliver Ruebenacker > Senior Software Engineer, Diabetes Portal > <http://www.type2diabetesgenetics.org/>, Broad Institute > <http://www.broadinstitute.org/> > >
