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VictoriaMetrics/docs/VictoriaLogs/logsql-examples.md
Aliaksandr Valialkin b7b3a9e9a3
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LogsQL examples

How to select recently ingested logs?

Run the following query:

_time:5m

It returns logs over the last 5 minutes by using _time filter. The logs are returned in arbitrary order because of performance reasons. Add sort pipe to the query if you need sorting the returned logs by some field (usually _time field):

_time:5m | sort by (_time)

If the number of returned logs is too big, it may be limited with the [`limit` pipe](https://docs.victoriametrics.com/victorialogs/logsql/#limit-pipe).
For example, the following query returns 10 most recent logs, which were ingested during the last 5 minutes:

```logsql
_time:5m | sort by (_time desc) | limit 10

See also:

How to select logs with the given word in log message?

Just put the needed word in the query. For example, the following query returns all the logs with the error word in log message:

error

If the number of returned logs is too big, then add _time filter for limiting the time range for the selected logs. For example, the following query returns logs with error word over the last hour:

error _time:1h

If the number of returned logs is still too big, then consider adding more specific filters to the query. For example, the following query selects logs with error word, which do not contain kubernetes word, over the last hour:

error !kubernetes _time:1h

The logs are returned in arbitrary order because of performance reasons. Add sort pipe for sorting logs by the needed fields. For example, the following query sorts the selected logs by _time field:

error _time:1h | sort by (_time)

See also:

How to skip logs with the given word in log message?

Use NOT logical filter. For example, the following query returns all the logs without the INFO word in the log message:

!INFO

If the number of returned logs is too big, then add _time filter for limiting the time range for the selected logs. For example, the following query returns matching logs over the last hour:

!INFO _time:1h

If the number of returned logs is still too big, then consider adding more specific filters to the query. For example, the following query selects logs without INFO word, which contain error word, over the last hour:

!INFO error _time:1h

The logs are returned in arbitrary order because of performance reasons. Add sort pipe for sorting logs by the needed fields. For example, the following query sorts the selected logs by _time field:

!INFO _time:1h | sort by (_time)

See also:

How to select logs with all the given words in log message?

Just enumerate the needed words in the query, by deliming them with whitespace. For example, the following query selects logs containing both error and kubernetes words in the log message:

error kubernetes

This query uses AND logical filter.

If the number of returned logs is too big, then add _time filter for limiting the time range for the selected logs. For example, the following query returns matching logs over the last hour:

error kubernetes _time:1h

If the number of returned logs is still too big, then consider adding more specific filters to the query. For example, the following query selects logs with error and kubernetes words from log streams containing container="my-app" field, over the last hour:

error kubernetes _stream:{container="my-app"} _time:1h

The logs are returned in arbitrary order because of performance reasons. Add sort pipe for sorting logs by the needed fields. For example, the following query sorts the selected logs by _time field:

error kubernetes _time:1h | sort by (_time)

See also:

How to select logs with some of the given words in log message?

Put the needed words into (...), by delimiting them with or. For example, the following query selects logs with error, ERROR or Error words in the log message:

(error or ERROR or Error)

This query uses OR logical filter.

If the number of returned logs is too big, then add _time filter for limiting the time range for the selected logs. For example, the following query returns matching logs over the last hour:

(error or ERROR or Error) _time:1h

If the number of returned logs is still too big, then consider adding more specific filters to the query. For example, the following query selects logs without error, ERROR or Error words, which do not contain kubernetes word, over the last hour:

(error or ERROR or Error) !kubernetes _time:1h

The logs are returned in arbitrary order because of performance reasons. Add sort pipe for sorting logs by the needed fields. For example, the following query sorts the selected logs by _time field:

(error or ERROR or Error) _time:1h | sort by (_time)

See also:

How to select logs from the given application instance?

Make sure the application is properly configured with stream-level log fields. Then just use _stream filter for selecting logs for the given application instance. For example, if the application contains job="app-42" and instance="host-123:5678" stream fields, then the following query selects all the logs from this application:

_stream:{job="app-42",instance="host-123:5678"}

If the number of returned logs is too big, it is recommended adding _time filter to the query in order to reduce the number of matching logs. For example, the following query returns logs for the given application for the last day:

_stream:{job="app-42",instance="host-123:5678"} _time:1d

If the number of returned logs is still too big, then consider adding more specific filters to the query. For example, the following query selects logs from the given log stream, which contain error word in the log message, over the last day:

_stream:{job="app-42",instance="host-123:5678"} error _time:1d

The logs are returned in arbitrary order because of performance reasons. Use sort pipe for sorting the returned logs by the needed fields. For example, the following query sorts the selected logs by _time:

_stream:{job="app-42",instance="host-123:5678"} _time:1d | sort by (_time)

See also:

How to count the number of matching logs?

Use count() stats function. For example, the following query returns the number of results returned by your_query_here:

your_query_here | count()

How to determine applications with the most logs?

Run the following query:

_time:5m | stats by (_stream) count() as logs | sort by (logs desc) | limit 10

This query returns top 10 application instances (aka log streams) with the most logs over the last 5 minutes.

This query uses the following LogsQL features:

  • _time filter for selecting logs on the given time range (5 minutes in the query above).
  • stats pipe for calculating the number of logs. per each _stream. count stats function is used for calculating the needed stats.
  • sort pipe for sorting the stats by logs field in descending order.
  • limit pipe for limiting the number of returned results to 10.

See also:

How to parse JSON inside log message?

It is better from performance and resource usage PoV to avoid storing JSON inside log message. It is recommended storing individual JSON fields and log fields instead according to VictoriaLogs data model.

If you have to store JSON inside log message or inside any other log fields, then the stored JSON can be parsed during query time via unpack_json pipe. For example, the following query unpacks JSON from the _msg field across all the logs for the last 5 minutes:

_time:5m | unpack_json

If you need to parse JSON array, then take a look at unroll pipe.

How to extract some data from text log message?

Use extract or extract_regexp pipe. For example, the following query extracts username and user_id fields from text log message:

_time:5m | extract "username=<username>, user_id=<user_id>,"

See also:

How to filter out data after stats calculation?

Use filter pipe. For example, the following query returns only log streams with more than 1000 logs over the last 5 minutes:

_time:5m | stats by (_stream) count() rows | filter rows:>1000

How to calculate the number of logs per the given interval?

Use stats by time bucket. For example, the following query returns per-hour number of logs with the error word for the last day:

_time:1d error | stats by (_time:1h) count() rows | sort by (_time)

This query uses sort pipe in order to sort per-hour stats by _time.

How to calculate the number of logs per every value of the given field?

Use stats by field. For example, the following query calculates the number of logs per level field for logs over the last 5 minutes:

_time:5m | stats by (level) count() rows

An alternative is to use field_values pipe:

_time:5m | field_values level

How to get unique values for the given field?

Use uniq pipe. For example, the following query returns unique values for the ip field over logs for the last 5 minutes:

_time:5m | uniq by (ip)

How to get unique sets of values for the given fields?

Use uniq pipe. For example, the following query returns unique sets for (host, path) fields over logs for the last 5 minutes:

_time:5m | uniq by (host, path)

How to return last N logs for the given query?

Use sort pipe with limit. For example, the following query returns the last 10 logs with the error word in the _msg field over the logs for the last 5 minutes:

_time:5m error | sort by (_time desc) limit 10

It sorts the matching logs by _time field in descending order and then selects the first 10 logs with the highest values for the _time field.

If the query is sent to /select/logsql/query HTTP API, then limit=N query arg can be passed to it in order to return up to N latest log entries. For example, the following command returns up to 10 latest log entries with the error word:

curl http://localhost:9428/select/logsql/query -d 'query=error' -d 'limit=10'