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Splunk eval null11/21/2023 ![]() I hope this article will remind you to know your data and never assume anything. Sometimes you will run into cases where reports or field extractions are accurate 99.9% of the time but once a month a log source comes in that doesn’t work with your field extraction and causes the report to have inaccuracies. I experienced similar issues in the real world, but the errors were hiding in millions and billions of events. But what I need is to write the value to be NULL. Another option would be to use the trim command to trim the trailing space.Īgain, these are just lab examples of field values or trailing spaces. I need to fill missing values from search items as NULL (not the string, but actual NULL values) I see options to check if the values is NULL (isnull) or even fill NULL values with a string (fillnull). To fix this issue we would need to either fix the existing field extraction or add a new inline field extraction. Now if we look at the raw data, we can see that for some reason there is a trailing space on some but not all the IP addresses. If we do an eval we can count the length of the field and as you can see, we have 10 character IP Addresses that are counting out as 11 characters. As you can see, we are sorting the IP_Address column but it’s not sorting correctly. eval() function JavaScript closest() JavaScript continue statement JS. In my next example, we are coalescing IP addresses from two sources. To replace these empty string fields with Unknown:Īs you can see now the search is working as expected. In this case, we can fix this by adding a replace command. The fillnull did not work because the fields are not null they contain empty strings. The stats command will ignore all null values of hostName. Double quotes around the text make it a string constant. But how could that be?! We did a fillnull! The case function is missing a default clause so any value of env not listed will set hostName to null. Use single quotes around text in the eval command to designate the text as a field name. ![]() However, when we take a closer look, we notice there are 9 events with blank entries for Known_Bad_IP. Without knowing the data, the person writing this search could easily be done here. I will do my best to demonstrate these to you but in a real-world scenario, it’s never as obvious as a blog post.įirst here is an example of a search that is counting IP Addresses with an “Unknown” status. This will show events that have been sent to the null que within the splunk. This can be confusing and even lead to inaccurate results. eval F5 Fun Stuff & Helpful Hints Hack Hygiene IIS Juniper Linux. In my career as a Splunk Consultant, I have run across numerous occasions where I was thrown off by what I thought were null field values or trailing spaces where I didn’t expect spaces to exist. Troubleshooting Null Field Values and Trailing Spaces
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