Compare metadata vs. data field results in log queries

TL;DR

Many logs contain a field like $d.severity, but it doesn’t always represent the standard severity level (e.g., ERROR, INFO, CRITICAL). It might indicate something else entirely — such as internal scoring, alerting status, or domain-specific meaning.

For log severity checks, you should always default to $m.severity, which is normalized by Coralogix at ingest. It guarantees consistent severity levels across all sources.

Unless $d.severity is deliberately used for a custom purpose in your schema, prefer $m.severity for filtering, grouping, or analyzing severity levels.

Problem / Use case

You're querying for logs with severity == ERROR and getting surprisingly low results. This often happens when querying the $d (user data) object instead of $m (metadata), which is where severity is typically stored.

For example, this query looks correct but in our test data it only returned 55 results:

source logs
| filter severity == 'error' && now() - timestamp:timestamp < 1d
| count

However, changing it to use metadata fields gives dramatically different results—nearly 10,000:

source logs
| filter $m.severity == ERROR && now() - $m.timestamp < 1d
| count

Query

This query compares the number of ERROR logs using $m.severity (the normalized, system-level severity) against $d.severity (the raw field in the log body). It filters each side independently for logs in the last 24 hours, counts them, and joins the results side-by-side for easy comparison. Use this pattern to validate whether your logs rely on $d.severity, and whether $m.severity is safe to use as the default.

source logs
| filter $m.severity == ERROR && now() - $m.timestamp < 1d
| count into log_m_fields
| create dummy_key from 'comparison'
| join (
    source logs
    | filter $d.severity.toLowerCase() == 'error' && now() - $d.timestamp:timestamp < 1d
    | count into log_d_fields
    | create dummy_key from 'comparison'
  )
  on left=>dummy_key == right=>dummy_key
  into copies
| choose copies.log_d_fields as log_d_fields, log_m_fields

Expected output

A table comparing log counts per day:

log_d_fields	log_m_fields
55	9914

This output highlights how querying $m.severity yields far more accurate results than $d.severity.

Variations

• Change the timestamp granularity (/1h, /1d) to get finer comparisons.
• Swap join for outer join to show missing values on either side.