We're in the process of migrating servers and thought we'd also upgrade Elasticsearch in the process.
However, when installing Elasticsearch 2.1.0 on the new servers (which are much more powerful than the old ones, with our MySQL benchmarks running about 40% faster) we saw a huge decrease in aggregation performance (between 50 and 100%).
Has there been any changes to configuration that might explain this change? I know that doc values are now the default (whereas before we only used them for some fields in our index) but that shouldn't have such a huge impact (according to documentation), should it?
When looking at the nightly benchmarks for Elasticsearch, I'm seeing that on 1st December a huge spike occurs which makes search performance (aggregations, term, phrase) about 70% slower, so maybe this is the culprit. However I'm not seeing anyone talking about it so maybe I'm misunderstanding something.
Before we start downgrading and comparing different versions, I thought I'd ask here in case anyone has any ideas that might help.