Splunk Search

Why am I not getting results running a search on an extracted field?

gcusello
Esteemed Legend

Hi at all,

I have a very strange behavior in one of my searches:

  • I extracted a field from a raw as a part of a word: 2016-04-13 12.12.45 ZZ1234567890123456789 and I need to take only the first 8 letters after the date ZZ123456;
  • I use the following regex ^.{20}(?\w{8}). It runs and I can extract my field and show it in my tables.

The problem is when I want to search using my field because if i write:

  index=xxx sourcetype=xxx Myfield="ZZ123456"

I don't get any results.

If I instead write:

  index=xxx sourcetype=xxx | search Myfield="ZZ123456"

I find the correct log.

The problem seems to be in the field extraction because if I extract the full string ^.{20}(?\w{21}), the search runs in both the situations, but if I want to use only a part of it, the search doesn't run.

Now I'm modifying all my searches, but it's a long job that I'd like to avoid.

Anyone has an idea of how to intervene?

Thank you in advance.

Bye.

Giuseppe

0 Karma
1 Solution

twinspop
Influencer

twinspop
Influencer

See this blog post for a good explanation on why this happens.

http://blogs.splunk.com/2011/10/07/cannot-search-based-on-an-extracted-field/

meenal901
Communicator

Hi Giussepe,

Your field extraction looks good. When you extract using 21 characters and run the search "index=xxx sourcetype=xxx", do you already have a field called "Myfield" in the interesting fields list? If yes, then it means your extraction is already saved in the props.conf of the search head.
If not, then this is a weird case of rex 🙂

0 Karma
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