# How to interpret a merge TRACE log?

**URL:** <https://discuss.elastic.co/t/how-to-interpret-a-merge-trace-log/68393>\
**Category:** Elasticsearch\
**Created:** [December 8, 2016, 4:50am UTC](https://discuss.elastic.co/t/how-to-interpret-a-merge-trace-log/68393 "2016-12-08T04:50:25Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Brad\_Jungsu\_Heo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/brad_jungsu_heo/32/13135_2.png) [@Brad\_Jungsu\_Heo](https://discuss.elastic.co/u/Brad_Jungsu_Heo)\
**Post date:** [December 8, 2016, 4:50am UTC](https://discuss.elastic.co/t/how-to-interpret-a-merge-trace-log/68393/1 "2016-12-08T04:50:25Z")

</div>

Hello.

After enabling merge log like this:

```auto
PUT /_cluster/settings
{
    "transient":
    {
        "logger.index.engine.lucene.iw":"TRACE"
    }
}

```

I'm getting tons of TRACE messages. One of merge thread executed during 1265.6s

```auto
merge thread elasticsearch[hostname1][[idx1][41]:
Lucene Merge Thread #2753]
estSize=5072.3 MB (written=5069.5 MB)
runTime=1265.6s (stopped=0.0s, paused=944.5s)
rate=5.0 MB/sec

```

But I'd like to know what `paused` means.

- Did merge thread pause for 944 second?
- Or Lucene indexing paused for 944 second?

I think merge thread has to work for about 1,000 seconds with 5MB rate to merge 5GB segment. So I don't get what 'paused=944.5s` means and what's the effect of long paused time.

Thanks for advanced answer.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [January 5, 2017, 4:51am UTC](https://discuss.elastic.co/t/how-to-interpret-a-merge-trace-log/68393/2 "2017-01-05T04:51:01Z")

</div>

Closed on January 5, 2017, 4:51am UTC

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