The detail meaning of esrally Final score?

Now I running esrally 0.3.2 successfully. And I also get the Final score. I have problem below:
Firstly: I think the score contain too many information, But as user I just need the most useful performance information of my elaticsearch?

Secondly: I don't know the detail meaning of many socore? just like:
1.Median Indexing Throughput [docs/s] | 12307 |, what is every doc size? I think one doc size is 1KB, the other doc is 1TB. It's very different between the little one and the large one.

2.Indexing time [min] | 164.045 |
| Merge time [min] | 32.3815 |
| Refresh time [min] | 8.82333 |
| Flush time [min] | 1.63852 |
| Merge throttle time [min] | 1.45482

Whether Indexing time is create index time or not?
Whether Flush time is flush index time or not?

  1. Query latency default (90.0 percentile) [ms] | 68.8676 |
    | Query latency default (99.0 percentile) [ms] | 77.6009 |
    | Query latency default (100 percentile) [ms] | 78.8328
    What's the meaning of 90.0/99.0/100 percentile? I don't konw the difference of them?

  2.            Median CPU usage (index) [%] |     887.7 |
    

| Median CPU usage (stats) [%] | 94.9 |
| Median CPU usage (search) [%] | 445.05 |

Why CPU usage percent > 100%? I know maybe relate about many core of server?

5.Total Young Gen GC [s] | 89.121 |
| Total Old Gen GC [s] | 12.274

I don't konw the meaning of Gen GC? Maybe I can google it.

6.Index size [GB] | 3.30111 |
| Totally written [GB] | 20.2123 |

Whether the index size is create Index size or not?

Just refer to the above question?
I think every score should explain the meaning ? May be give the meaning list is best!

Thanks!

I'd like to think the answer to something so profound would be;

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Douglas Adams, 1998

Hi @laoyang360

I think that is in the eye of the beholder. Rally is used by developers of Elasticsearch, sysadmins, application developers, consultants, ... so there is no one size fits all.

There is an open ticket to document all metrics key names: https://github.com/elastic/rally/issues/109

The documents depend on the track. You can look at them in ~/.rally/benchmarks/data/. E.g. for the "geonames" track, you have to look at ~/.rally/benchmarks/data/geonames.documents.json. Each line in this file is one document and they are usually similar in size.

This is the amount of time that the benchmarked clusters spent indexing. Note that this is not Wall clock time but total runtime (i.e. if you have two indexing threads running concurrently for 5 minutes, this would mean that we'd report 10 minutes).

See https://en.wikipedia.org/wiki/Percentile

Yes

Total runtime of the young generation garbage collector and the old generation garbage collector during the benchmark.

  • Index size is the final index size on your disk.
  • Totally written is the number of bytes that have been written to disk. As Lucene merges segments in the background you usually write more bytes than your final index size.

Daniel

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I have just added a description of each metric that Rally captures, see http://esrally.readthedocs.io/en/latest/metrics.html#metric-keys

Note that these are not the names in the command line report but rather the metric keys that are stored internally. If you use a dedicated metrics store you can create graphs in Kibana based on this information.

If anything is unclear, bug reports or pull requests are welcome. :slight_smile:

Daniel

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Hi, @danielmitterdorfer:
I'm very glad to see the new metric document, your are very efficient.
I have three question about what your said:

First, the two results of disk_io_write_bytes and disk_io_read_bytes are not included in my esrally running result.

Second, How to create graph in kibana based on this result information?
Now, I already installed kibana, and it running port is 5601. I already used it to analyze data, just need to import the result date to elasticsearch? If you have simple method, please tell me.

Third, the graph of https://www.elastic.co/blog/announcing-rally-benchmarking-for-elasticsearch
is based on the kibana or other tools? I want to know the detail information.

Thanks.

Hi @laoyang360,

disk_io_write_bytes is the name of the metric in the metrics store. It's reported on the command line as "Totally written" (and converted to GB so it's easier to read). We do not report "disk_io_read_bytes" indeed on the command line. I did not consider this metric important enough for a summary.

If you're really interested in detailed analysis, you should not just look at the command line report but instead set up a dedicated Elasticsearch cluster as metrics store and point Kibana to it. The docs on advanced configuration in Rally show what you need to do to configure a dedicate Elasticsearch metrics store.

The raw information (i.e. the metrics records) is stored in the Elasticsearch metrics store. You then need to define queries in Kibana. The metrics documentation in Rally shows concrete examples of the structure of metrics records and also describe their meaning. Based on that you need to write the queries in Kibana in which you're interested. I have not added a tutorial or specific documentation on that but you can look at the Kibana dashboard of our nightly benchmarks. Although we grant anonymous users only read only rights, you can still explore everything and inspect which queries we used to build the graphs. That should get you started.

I am not sure to which of the many graphs in the blog post you refer to. Can you please post the link to the specific picture? For most pictures I mentioned the tool that has been used in the text of the blog post. The only graph that requires some custom tooling is the JIT compiler events graph (as the jit telemetry device emits only text). I only created this visualization for a one-time visualization. The rest is either done in Kibana or Java flight recorder.

Daniel

Hi, @danielmitterdorfer:
I refer to your document: http://esrally.readthedocs.io/en/latest/configuration.html#advanced-configuration

And this time I running esrally Advanced Configuration ok, and then running esrally as follow:

[elasticsearch@laoyang root]$ esrally

    ____        ____
   / __ \____ _/ / /_  __
  / /_/ / __ `/ / / / / /
 / _, _/ /_/ / / / /_/ /
/_/ |_|\__,_/_/_/\__, /
                /____/


Writing additional logs to /home/elasticsearch/.rally/benchmarks/races/2016-08-10-06-50-06/local/logs/rally_out.log

Preparing for race (might take a few moments) ...
  Building from sources ...
Racing on track [geonames] and challenge [append-no-conflicts] with car [defaults]
  Benchmarking indexing at 12590.4 docs/s                            [100% done]
  Benchmarking stats (warmup iteration 100/100)                      [100% done]
  Benchmarking stats (iteration 100/100)                             [100% done]
  Benchmarking search (warmup iteration 100/100)                     [100% done]
  Benchmarking search (iteration 100/100)                            [100% done]

The follow is my es head plugin and kibana running result:

From the esrally running result, I find the Index size [GB] | 3.26797 ,
but my es head plugin and kibana just have the basic information of rally,

Do you know why the difference of esrally result and the head plugin and kibana?

Hi @laoyang360,

You did see that I referred you to our benchmark results page in Kibana, didn't you? Because this would answer your question perfectly...

For this specific metric, see https://elasticsearch-benchmark-analytics.elastic.co/app/kibana#/visualize/edit/Index-disk-usage

Daniel

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Hi, @danielmitterdorfer:

Ok, refer to the link above, I already get the correct kibana result.

Thanks!

Hi @laoyang360,

glad that it worked out. The only thing that worries me is that your index size is steadily increasing. That does not look right (it should stay roughly constant; just check our nightly benchmark graph).

Daniel

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Hi, @danielmitterdorfer:
I think your need not worry, Because I only running once, the kibana result only show the two result below:
one is final_index_size_bytes; size: Index size [GB] | 3.26797
the other one is disk_io_write_bytes OR name:disk_io_write_bytes_index , size: Totally written [GB] | 20.7748

So, the result show is correct.

While compare to your link graph, because you test for a long time, so your index size is roughly constant.

Ah, you're right. I did not see that you added two metrics.

Daniel

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Hi, @danielmitterdorfer:
I want to know the esrally running time, but from the running result, I can't find it.

Median Indexing Throughput [docs/s] | 12307
| Index size [GB] | 3.30111 |
| Totally written [GB] | 20.2123 |
| Total Young Gen GC [s] | 89.121 |
| Total Old Gen GC [s] | 12.274 |

Your know, from the above result, I get that I already writed 20.2123GB, and the Index throughput is 12307 doc/s, and every doc size is about 40Byte. So the written time is = (20.2123102410241024)/(1230740)=44086.276s = 734.771min=12.25h

Clearly, the calculate result is not correct.

So, I want to know the correct time of rally running?
Or, any other useful param about the disk written rate would be helpful.
Thanks!

Hi, @danielmitterdorfer:
From the log of esrally which location is
/home/elasticsearch/.rally/benchmarks/races/2016-08-12-01-59-58/LOCAL/logs, I get the time information as follows:
the esrally running begin time: 2016-08-12 01:59:58
the esrally running end time: 2016-08-12 02:27:52,
and the total time span is: 28m 54s.

Hi @laoyang360,

I think you are comparing apples to oranges here:

20.2 GB have been written in total during the benchmark by Elasticsearch. However, this includes also segment merges of Lucene and if you compare that to the final index size you can see that they are a significant contributing factor. So the actual indexing operations are not the only cause of disk writes.

If you want to know the indexing rate in byte / s you should rather calculate 12307 [document / s] * 40 [byte / document] = 0.47MB/s (but this is just a very rough calculation).

I understand you're looking for some new metric. For which purpose do you want to use it (i.e. what information do you gain from it)? Maybe we can come up with something suitable then.

Daniel

Hi @danielmitterdorfer:
Thank your for your reply.
I just what to know the rate of write date to disk.
Until now, I have no concrete scene, I just use esrally for elasticsearch performance testing .
As you said, the indexing rate is about 0.47MB/s, I think this rate is may be equal with the rate of write date to disk.

Until now, only me use esrally for elasticsearch performance testing in our team.
I'll testing it for several days, If It's robust enough, I'll recommend our team using it .

Hi @laoyang360,

I got that but why do want that metric, i.e. what conclusions do you draw based on this metric?

Having that said, these are the disk related metrics we can get from the psutil library that we use internally in Rally:

http://pythonhosted.org/psutil/#psutil.disk_io_counters

We could, for example, sample the number of bytes written once per second.

No, the indexing rate is definitely not the same as the number of bytes written / second to disk. Elasticsearch (or rather Lucene) has to manage other data structures too, it compresses content and it also merges segments. All these things (and probably a lot more) cause differences between the number of bytes written to disk and the indexing rate in bytes/s.

Daniel

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