Estimate distinct log values with approx_count_distinct

Estimate how many distinct values appear in your logs when an exact count would create too many series.

count by (<field>) returns one series for every distinct value. For a field such as a user ID, IP address, or session token, that series count can hit Loki’s maximum series limit or time out the query. approx_count_distinct estimates the number of distinct values of a label or extracted field and returns one series per group.

logql Copy

approx_count_distinct(
  user_id,
  {job="webapp"} | json [1d]
)

logql Copy

approx_count_distinct(
  ip_address,
  {job="api"} | json [1d]
) by (version)

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