# Rally 0.4.0 released

**URL:** <https://discuss.elastic.co/t/rally-0-4-0-released/59405>\
**Category:** Announcements\
**Created:** [August 31, 2016, 9:07am UTC](https://discuss.elastic.co/t/rally-0-4-0-released/59405 "2016-08-31T09:07:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![danielmitterdorfer](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/danielmitterdorfer/32/110510_2.png) [@danielmitterdorfer](https://discuss.elastic.co/u/danielmitterdorfer)\
**Post date:** [August 31, 2016, 9:07am UTC](https://discuss.elastic.co/t/rally-0-4-0-released/59405/1 "2016-08-31T09:07:13Z")

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Today we're proud to announce Rally 0.4.0. Although not much changed from the outside, Rally 0.4.0 is basically a rewrite of one of its core components: the load generator.

## How to...?

- ... upgrade: `pip3 install --upgrade esrally`
- ... install: `pip3 install esrally`

Note: Depending on your system setup you probably need to prepend these commands with `sudo`.

Please follow the [installation instructions](https://esrally.readthedocs.io/en/latest/#first-time-setup) for a first time install though.

## Changes

Contrary to the old thread-based approach, this approach uses now multiple processes and has shown a better peak (and mean) throughput in driver stress tests, can execute search requests in parallel (although we will need to improve that a bit in an upcoming maintenance version).

We also got rid of a few conceptual problems of the old driver:

- Rally 0.4.0 does not suffer anymore from a problem called "coordinated omission" that many - even very popular - load generators like JMeter have. If you want to know more about this phenomenon watch the talk [How NOT to measure latency by Gil Tene on Youtube](https://www.youtube.com/watch?v=lJ8ydIuPFeU).
- Rally also allows throughput throttling (which is basically a consequence of eliminating coordinated omission).
- We show service time and latency separately in the results (see their [definition in the docs](http://esrally.readthedocs.io/en/latest/metrics.html#metric-keys)).
- You can specify the warmup time period for bulk index operations in the track. Previously, this was hard-coded in Rally.

Besides, Rally as well as the official Rally tracks dropped support for Elasticsearch 5.0.0-alpha1 and 5.0.0-alpha2, all other versions of Elasticsearch should still work.

## What's next?

This is a significant step forward for Rally. We plan to smooth out a few things in the coming 0.4 releases:

- [Improve feedback messages](https://github.com/elastic/rally/issues/145): As of Rally 0.4.0 the fine-grained feedback is gone and Rally will update the percentage count only after each phase. This means you'll see 0% progress for quite some time but we'll plan to reintroduce the old feature soon again.
- [Add a ramp-down phase](https://github.com/elastic/rally/issues/144): Currently we only have a warmup phase and a measurement phase in Rally. For multiple reasons it makes sense to also include a ramp-down phase in benchmarks.
- We'll also attempt to bring back CPU statistics per benchmark phase although this could get a bit hairy.

After that the new big goal on the roadmap is finally [support for benchmarks of arbitrarily large clusters](https://github.com/elastic/rally/issues/71) in [version 0.5.0](https://github.com/elastic/rally/milestone/8). Internally, we're now equipped to do that with 0.4.0.

If you have questions or feedback, please just post in the [Rally forum](https://discuss.elastic.co/c/rally). File any issues in the [Rally Github repository](https://github.com/elastic/rally).

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 9:47pm UTC](https://discuss.elastic.co/t/rally-0-4-0-released/59405/2 "2017-07-05T21:47:05Z")

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