Agreed w/ ES not being the durable data store. I would recommend treating it as ephemeral, and using Cassandra as your source of truth. Keep in mind if you change your ES index mapping, you’ll require a full reindex in order to search the data properly. It’s not like adding a secondary index w/ a DB, where it’ll go back and take care of it for you.
Jon On May 3, 2014, at 12:31 AM, DuyHai Doan <doanduy...@gmail.com> wrote: > Hello Tim > > You're absolutely right about ES for the query part. This is the perfect fit > for complex queries. Now regarding your question: > > "What advantages does Cassandra give me over ES?" --> linear scalability & > durability. ES is just a super index cluster. I've talked to ES guys. If they > do not sell ES right now as a "database for complex search" it's because > there is no strong guarantee about durability for your data. Many people just > live with it and it's fine. Also, if you store the original data and just > pump it into ES it's also fine. > > > > > On Sat, May 3, 2014 at 9:14 AM, Tim Uckun <timuc...@gmail.com> wrote: > Hey all. > > I have been trying out some data stores for time series data and Cassandra > was the first on my list because so many people are using it for the same > purpose. I have read many articles on how to model my time series data and > tried several variations of schemas which I thought made sense for my data > but I have really struggled to run some complex queries I need to run. This > has led me down a kind of a rabbit hole of trying to create various > "materialized views" and shotgunning the data into multiple tables which > might be able to run my queries. > > In the mean time I also took the same data and pumped it into Elasticsearch > and was able to run almost all the queries I needed without doing anything > fancy. Just put the data in, and run your query. The new aggregations in ES > are pretty slick although they don't seem to be 100% accurate compared to > running the same query in Postgres. > > My question is this. What advantages does Cassandra give me over ES? Does > it compact the data better? Is it faster to query once your data sizes are > huge? Does it use less bandwidth? Is it easier to administer? > > I know there must be very compelling reasons to use C* because so many > companies are depending on it for their bread and butter so I'd love to hear > your take. > > Thanks. >
