# Slow log took time questions
**URL:** https://discuss.elastic.co/t/slow-log-took-time-questions/337384
**Category:** Elasticsearch
**Tags:** rally
**Created:** [July 2, 2023, 2:08am UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384 "2023-07-02T02:08:42Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@tengfei225](https://discuss.elastic.co/u/tengfei225)
#### Post date: [July 2, 2023, 2:08am UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384/1 "2023-07-02T02:08:42Z")
Hi
I have some questions about the slow log took time
I want to only get the process time in elasticsearch server using esrally to do the benchmark
So I opened the slow log like below
```auto
PUT /myIndex/_settings
{
"index.search.slowlog.threshold.fetch.trace": "0s",
"index.search.slowlog.threshold.query.trace": "0s",
}
```
then I can find all the slow logs in the elastic-cloud-logs\* index, but if I run a query ,there will be two documents logged , one component is query and another is fetch, so which time should I use as the total processing time in es including both query and fetch phase
query phase log
```auto
{
"slowlog": {
"cluster": {},
"elasticsearch.slowlog.search_type": "QUERY_THEN_FETCH",
"elasticsearch.slowlog.took": "278.3micros",
"elasticsearch.slowlog.message": "[5c43591a_608d_493f_94aa_5da18abecabc][0]",
"elasticsearch.slowlog.stats": "[]",
"elasticsearch.slowlog.source": "{}",
"elasticsearch.slowlog.id": "null",
"node": {},
"elasticsearch.slowlog.total_shards": "1",
"elasticsearch.slowlog.took_millis": "0",
"elasticsearch.slowlog.total_hits": "10001+ hits"
}
}
```
fetch phase log
```auto
{
"slowlog": {
"cluster": {},
"elasticsearch.slowlog.search_type": "QUERY_THEN_FETCH",
"elasticsearch.slowlog.took": "1.4ms",
"elasticsearch.slowlog.message": "[5c43591a_608d_493f_94aa_5da18abecabc][0]",
"elasticsearch.slowlog.stats": "[]",
"elasticsearch.slowlog.source": "{}",
"elasticsearch.slowlog.id": "null",
"node": {},
"elasticsearch.slowlog.total_shards": "1",
"elasticsearch.slowlog.took_millis": "1",
"elasticsearch.slowlog.total_hits": "10001+ hits"
}
}
```
Does the "elasticsearch.slowlog.took": "278.3micros" includes both the query and fetch phase time or need to add the time in fetch phase ?
Thanks
---
### Author:  [@Quentin\_Pradet](https://discuss.elastic.co/u/Quentin_Pradet)
#### Post date: [July 3, 2023, 6:24am UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384/2 "2023-07-03T06:24:08Z")
Hello @tengfei225!
You should use the sum of both times. In that case that would be 1.4ms + 278.3micros, that is 1.4ms + 0.3ms or 1.7ms. I would expect the `took` time reported by the request result to be 2 as 1.7ms rounds to 2ms.
Many Rally operations return that result already, so if you configure metrics ([Metrics - Rally 2.8.0 documentation](https://esrally.readthedocs.io/en/stable/metrics.html)) you may not have to configure slowlog. Search for took in [Track Reference - Rally 2.8.0 documentation](https://esrally.readthedocs.io/en/stable/track.html) to see all operations that store the `took` time. (In some cases enabling `detailed-results` is needed though.)
That said, `took` is a server metric, and in most cases you will care more about the latency as seen by the client. See [Frequently Asked Questions (FAQ) - Rally 2.8.0 documentation](https://esrally.readthedocs.io/en/stable/faq.html#what-do-latency-and-service-time-mean-and-how-do-they-relate-to-the-took-field-that-elasticsearch-returns) for more details.
---
### Author:  [@tengfei225](https://discuss.elastic.co/u/tengfei225)
#### Post date: [July 3, 2023, 8:12am UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384/3 "2023-07-03T08:12:13Z")
Thanks @Quentin_Pradet , your reply helps a lot .
Is this reasonable if I separate the query and fetch phase, like I only use fetch phase took time to benchmark the \_source/doc\_value/stored since we have some test cases about which one from \_source/doc\_value/stored is better to retrieve data ? Will this way be more accurate ?
---
### Author:  [@Quentin\_Pradet](https://discuss.elastic.co/u/Quentin_Pradet)
#### Post date: [July 3, 2023, 12:25pm UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384/4 "2023-07-03T12:25:44Z")
Well, no, using fetch phase isn't a very accurate measurement. It will exclude various things:
- Query phase
- Possibly time spent in queues inside Elasticsearch (I don't know the details enough to tell)
- Time needed to send the request to Elasticsearch
- Time needed to serialize the JSON response
- Time needed to send the response to a client
See [Search API | Elasticsearch Guide [8.8] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-search.html#search-api-response-body) for the last three bullets.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 31, 2023, 12:26pm UTC](https://discuss.elastic.co/t/slow-log-took-time-questions/337384/5 "2023-07-31T12:26:11Z")
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