The simplest LogsQL query is just a [word](#word), which must be found in the [log message](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
For example, the following query finds all the logs with `error` word:
```logsql
error
```
If the queried [word](#word) clashes with LogsQL keywords, then just wrap it into quotes.
For example, the following query finds all the log messages with `and` [word](#word):
```logsql
"and"
```
It is OK to wrap any word into quotes. For example:
```logsql
"error"
```
Moreover, it is possible to wrap phrases containing multiple words in quotes. For example, the following query
finds log messages with the `error: cannot find file` phrase:
This query consists of two [filters](#filters) joined with `AND` [operator](#logical-filter):
- The filter on the `error` [word](#word).
- The filter on the [`_time` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#time-field).
The `AND` operator means that the [log entry](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) must match both filters in order to be selected.
Typical LogsQL query constists of multiple [filters](#filters) joined with `AND` operator. It may be tiresome typing and then reading all these `AND` words.
So LogsQL allows omitting `AND` words. For example, the following query is equivalent to the query above:
Suppose the query above selects too many rows because some buggy app pushes invalid error logs to VictoriaLogs. Suppose the app adds `buggy_app` [word](#word) to every log line.
Then the following query removes all the logs from the buggy app, allowing us paying attention to the real errors:
This query uses `NOT` [operator](#logical-filter) for removing log lines from the buggy app. The `NOT` operator is used frequently, so it can be substituted with `!` char.
So the following query is equivalent to the previous one:
Note that the parentheses are required here, since otherwise the query won't return the expected results.
The query `error !buggy_app OR foobar` is interpreted as `(error AND NOT buggy_app) OR foobar`. This query may return error logs
from the buggy app if they contain `foobar` [word](#word). This query also continues returning all the error logs from the second buggy app.
This is because of different priorities for `NOT`, `AND` and `OR` operators.
Read [these docs](#logical-filter) for more details. There is no need in remembering all these priority rules -
just wrap the needed query parts into explicit parentheses if you aren't sure in priority rules.
As an additional bonus, explicit parentheses make queries easier to read and maintain.
Queries above assume that the `error` [word](#word) is stored in the [log message](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
This word can be stored in other [field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) such as `log.level`.
How to select error logs in this case? Just add the `log.level:` prefix in front of the `error` word:
What if the application identifier - such as `buggy_app` and `foobar` - is stored in the `app` field? Correct - just add `app:` prefix in front of `buggy_app` and `foobar`:
The `app` field uniquely identifies the application instance if a single instance runs per each unique `app`.
In this case it is recommended associating the `app` field with [log stream fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#stream-fields)
This query completely skips scanning for logs from `buggy_app` and `foobar` apps, thus significantly reducing disk read IO and CPU time
needed for performing the query.
Finally, it is recommended reading [performance tips](#performance-tips).
Now you are familiar with LogsQL basics. Read [query syntax](#query-syntax) if you want to continue learning LogsQL.
### Key concepts
#### Word
LogsQL splits all the [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) into words
delimited by non-word chars such as whitespace, parens, punctuation chars, etc. For example, the `foo: (bar,"тест")!` string
is split into `foo`, `bar` and `тест` words. Words can contain arbitrary [utf-8](https://en.wikipedia.org/wiki/UTF-8) chars.
These words are taken into account by full-text search filters such as
[word filter](#word-filter), [phrase filter](#phrase-filter) and [prefix filter](#prefix-filter).
#### Query syntax
LogsQL query consists of the following parts delimited by `|`:
- [Filters](#filters), which select log entries for further processing. This part is required in LogsQL. Other parts are optional.
- Optional [stream context](#stream-context), which allows selecting surrounding log lines for the matching log lines.
- Optional [transformations](#transformations) for the selected log fields.
For example, an additional fields can be extracted or constructed from existing fields.
- Optional [post-filters](#post-filters) for post-filtering of the selected results. For example, post-filtering can filter
results based on the fields constructed by [transformations](#transformations).
- Optional [stats](#stats) transformations, which can calculate various stats across selected results.
- Optional [sorting](#sorting), which can sort the results by the sepcified fields.
- Optional [limiters](#limiters), which can apply various limits on the selected results.
## Filters
LogsQL supports various filters for searching for log messages (see below).
They can be combined into arbitrary complex queries via [logical filters](#logical-filter).
Filters are applied to [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field) by default.
If the filter must be applied to other [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model),
then its' name followed by the colon must be put in front of the filter. For example, if `error` [word filter](#word-filter) must be applied
to the `log.level` field, then use `log.level:error` query.
Field names and filter args can be put into quotes if they contain special chars, which may clash with LogsQL syntax. LogsQL supports quoting via double quotes `"`,
single quotes `'` and backticks:
```logsql
"some 'field':123":i('some("value")') AND `other"value'`
```
If doubt, it is recommended quoting field names and filter args.
- [Time filter](#time-filter) - matches logs with [`_time` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#time-field) in the given time range
- [Stream filter](#stream-filter) - matches logs, which belong to the given [streams](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#stream-fields)
- [Word filter](#word-filter) - matches logs with the given [word](#word)
- [Phrase filter](#phrase-filter) - matches logs with the given phrase
- [Prefix filter](#prefix-filter) - matches logs with the given word prefix or phrase prefix
- [Empty value filter](#empty-value-filter) - matches logs without the given [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
- [Any value filter](#any-value-filter) - matches logs with the given non-empty [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
- [Exact filter](#exact-filter) - matches logs with the exact value
- [Exact prefix filter](#exact-prefix-filter) - matches logs starting with the given prefix
- [Case-insensitive filter](#case-insensitive-filter) - matches logs with the given case-insensitive word, phrase or prefix
- [Sequence filter](#sequence-filter) - matches logs with the given sequence of words or phrases
- [Regexp filter](#regexp-filter) - matches logs for the given regexp
- [Range filter](#range-filter) - matches logs with numeric [field values](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in the given range
- [IPv4 range filter](#ipv4-range-filter) - matches logs with ip address [field values](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in the given range
- [String range filter](#string-range-filter) - matches logs with [field values](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in the given string range
- [Length range filter](#length-range-filter) - matches logs with [field values](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) of the given length range
- [Logical filter](#logical-filter) - allows combining other filters
VictoriaLogs scans all the logs per each query if it doesn't contain the filter on [`_time` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#time-field).
-`_time:YYYY-MM-DD` - matches all the logs for the particular day by UTC. For example, `_time:2023-04-25` matches logs on April 25, 2023 by UTC.
-`_time:YYYY-MM` - matches all the logs for the particular month by UTC. For example, `_time:2023-02` matches logs on February, 2023 by UTC.
-`_time:YYYY` - matches all the logs for the particular year by UTC. For example, `_time:2023` matches logs on 2023 by UTC.
-`_time:YYYY-MM-DDTHH` - matches all the logs for the particular hour by UTC. For example, `_time:2023-04-25T22` matches logs on April 25, 2023 at 22 hour by UTC.
-`_time:YYYY-MM-DDTHH:MM` - matches all the logs for the particular minute by UTC. For example, `_time:2023-04-25T22:45` matches logs on April 25, 2023 at 22:45 by UTC.
-`_time:YYYY-MM-DDTHH:MM:SS` - matches all the logs for the particular second by UTC. For example, `_time:2023-04-25T22:45:59` matches logs on April 25, 2023 at 22:45:59 by UTC.
- It is recommended specifying the smallest possible time range during the search, since it reduces the amounts of log entries, which need to be scanned during the query.
- While LogsQL supports arbitrary number of `_time:...` filters at any level of [logical filters](#logical-filter),
it is recommended specifying a single `_time` filter at the top level of the query.
- See [other performance tips](#performance-tips).
See also:
- [Stream filter](#stream-filter)
- [Word filter](#word-filter)
### Stream filter
VictoriaLogs provides an optimized way to select log entries, which belong to particular [log streams](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#stream-fields).
-`multiple errors occurred`, since the `errors` word doesn't match `error` word. Use `error*` for this case. See [these docs](#prefix-filter) for details.
By default the given [word](#word) is searched in the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the word and put a colon after it
if it must be searched in the given field. For example, the following query returns log entries containing the `error` [word](#word) in the `log.level` field:
```logsql
log.level:error
```
Both the field name and the word in the query can contain arbitrary [utf-8](https://en.wikipedia.org/wiki/UTF-8)-encoded chars. For example:
```logsql
поле:значение
```
Both the field name and the word in the query can be put inside quotes if they contain special chars, which may clash with the query syntax.
For example, the following query searches for the ip `1.2.3.45` in the field `ip:remote`:
```logsql
"ip:remote":"1.2.3.45"
```
See also:
- [Phrase filter](#phrase-filter)
- [Exact filter](#exact-filter)
- [Prefix filter](#prefix-filter)
- [Logical filter](#logical-filter)
### Phrase filter
Is you need to search for log messages with the specific phrase inside them, then just wrap the phrase in quotes.
The phrase can contain any chars, including whitespace, punctuation, parens, etc. They are taken into account during the search.
-`ssh login fail`, since the message misses `:` char just after the `ssh`.
Use `seq("ssh", "login", "fail")` query if log messages with the sequence of these words must be found. See [these docs](#sequence-filter) for details.
-`login fail: ssh error`, since the message doesn't contain the full phrase requested in the query. If you need matching a message
with all the [words](#word) listed in the query, then use `ssh AND login AND fail` query. See [these docs](#logical-filter) for details.
-`ssh: login failed`, since the message ends with `failed` [word](#word) instead of `fail` word. Use `"ssh: login fail"*` query for this case.
See [these docs](#case-insensitive-filter) for details.
By default the given phrase is searched in the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the phrase and put a colon after it
if it must be searched in the given field. For example, the following query returns log entries containing the `cannot open file` phrase in the `event.original` field:
```logsql
event.original:"cannot open file"
```
Both the field name and the phrase can contain arbitrary [utf-8](https://en.wikipedia.org/wiki/UTF-8)-encoded chars. For example:
```logsql
сообщение:"невозможно открыть файл"
```
The field name can be put inside quotes if it contains special chars, which may clash with the query syntax.
For example, the following query searches for the `cannot open file` phrase in the field `some:message`:
```logsql
"some:message":"cannot open file"
```
See also:
- [Exact filter](#exact-filter)
- [Word filter](#word-filter)
- [Prefix filter](#prefix-filter)
- [Logical filter](#logical-filter)
### Prefix filter
If you need to search for log messages with [words](#word) / phrases containing some prefix, then just add `*` char to the end of the [word](#word) / phrase in the query.
For example, the following query returns [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field), which contain [words](#word) with `err` prefix:
```logsql
err*
```
This query matches the following [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field):
-`err: foobar`
-`cannot open file: error occurred`
This query doesn't match the following log messages:
-`Error: foobar`, since the `Error` [word](#word) starts with capital letter. Use `i(err*)` for this case. See [these docs](#case-insensitive-filter) for details.
-`fooerror`, since the `fooerror` [word](#word) doesn't start with `err`. Use `re("err")` for this case. See [these docs](#regexp-filter) for details.
Prefix filter can be applied to [phrases](#phrase-filter). For example, the following query matches
[log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field) containing phrases with `unexpected fail` prefix:
```logsql
"unexpected fail"*
```
This query matches the following [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field):
-`unexpected fail: IO error`
-`error:unexpected failure`
This query doesn't match the following log messages:
-`unexpectedly failed`, since the `unexpectedly` doesn't match `unexpected` [word](#word). Use `unexpected* AND fail*` for this case.
See [these docs](#logical-filter) for details.
-`failed to open file: unexpected EOF`, since `failed` [word](#word) occurs before the `unexpected` word. Use `unexpected AND fail*` for this case.
See [these docs](#logical-filter) for details.
By default the prefix filter is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the needed [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the prefix filter
in order to apply it to the given field. For example, the following query matches `log.level` field containing any word with the `err` prefix:
```logsql
log.level:err*
```
If the field name contains special chars, which may clash with the query syntax, then it may be put into quotes in the query.
For example, the following query matches `log:level` field containing any word with the `err` prefix.
```logsql
"log:level":err*
```
Performance tips:
- Prefer using [word filters](#word-filter) and [phrase filters](#phrase-filter) combined via [logical filter](#logical-filter)
instead of prefix filter.
- Prefer moving [word filters](#word-filter) and [phrase filters](#phrase-filter) in front of prefix filter when using [logical filter](#logical-filter).
- See [other performance tips](#performance-tips).
See also:
- [Exact prefix filter](#exact-prefix-filter)
- [Word filter](#word-filter)
- [Phrase filter](#phrase-filter)
- [Exact-filter](#exact-filter)
- [Logical filter](#logical-filter)
### Empty value filter
Sometimes it is needed to find log entries without the given [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model).
This can be performed with `log_field:""` syntax. For example, the following query matches log entries without `host.hostname` field:
```logsql
host.hostname:""
```
See also:
- [Any value filter](#any-value-filter)
- [Word filter](#word-filter)
- [Logical filter](#logical-filter)
### Any value filter
Sometimes it is needed to find log entries containing any non-empty value for the given [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model).
This can be performed with `log_field:*` syntax. For example, the following query matches log entries with non-empty `host.hostname` field:
```logsql
host.hostname:*
```
See also:
- [Empty value filter](#empty-value-filter)
- [Prefix filter](#prefix-filter)
- [Logical filter](#logical-filter)
### Exact filter
The [word filter](#word-filter) and [phrase filter](#phrase-filter) return [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field),
which contain the given word or phrase inside them. The message may contain additional text other than the requested word or phrase. If you need searching for log messages
or [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field) with the exact value, then use the `exact(...)` filter.
For example, the following query returns log messages wih the exact value `fatal error: cannot find /foo/bar`:
```logsql
exact("fatal error: cannot find /foo/bar")
```
The query doesn't match the following log messages:
-`fatal error: cannot find /foo/bar/baz` or `some-text fatal error: cannot find /foo/bar`, since they contain an additional text
other than the specified in the `exact()` filter. Use `"fatal error: cannot find /foo/bar"` query in this case. See [these docs](#phrase-filter) for details.
-`FATAL ERROR: cannot find /foo/bar`, since the `exact()` filter is case-sensitive. Use `i("fatal error: cannot find /foo/bar")` in this case.
See [these docs](#case-insensitive-filter) for details.
By default the `exact()` filter is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the `exact()` filter and put a colon after it
if it must be searched in the given field. For example, the following query returns log entries with the exact `error` value at `log.level` field:
```logsql
log.level:exact("error")
```
Both the field name and the phrase can contain arbitrary [utf-8](https://en.wikipedia.org/wiki/UTF-8)-encoded chars. For example:
```logsql
log.уровень:exact("ошибка")
```
The field name can be put inside quotes if it contains special chars, which may clash with the query syntax.
For example, the following query matches the `error` value in the field `log:level`:
By default the `exact()` filter is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the `exact()` filter and put a colon after it
if it must be searched in the given field. For example, the following query returns log entries with `log.level` field, which starts with `err` prefix:
Sometimes it is needed to locate log messages with a field containing one of the given values. This can be done with multiple [exact filters](#exact-filter)
See the [Roadmap](https://docs.victoriametrics.com/VictoriaLogs/Roadmap.html) for details.
See also:
- [Exact filter](#exact-filter)
- [Word filter](#word-filter)
- [Phrase filter](#phrase-filter)
- [Prefix filter](#prefix-filter)
- [Logical filter](#logical-filter)
### Case-insensitive filter
Case-insensitive filter can be applied to any word, phrase or prefix by wrapping the corresponding [word filter](#word-filter),
[phrase filter](#phrase-filter) or [prefix filter](#prefix-filter) into `i()`. For example, the following query returns
log messages with `error` word in any case:
```logsql
i(error)
```
The query matches the following [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field):
-`unknown error happened`
-`ERROR: cannot read file`
-`Error: unknown arg`
-`An ErRoR occured`
The query doesn't match the following log messages:
-`FooError`, since the `FooError` [word](#word) has superflouos prefix `Foo`. Use `re("(?i)error")` for this case. See [these docs](#regexp-filter) for details.
-`too many Errors`, since the `Errors` [word](#word) has superflouos suffix `s`. Use `i(error*)` for this case.
By default the `i()` filter is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the needed [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the filter
in order to apply it to the given field. For example, the following query matches `log.level` field containing `error` [word](#word) in any case:
```logsql
log.level:i(error)
```
If the field name contains special chars, which may clash with the query syntax, then it may be put into quotes in the query.
For example, the following query matches `log:level` field containing `error` [word](#word) in any case.
```logsql
"log:level":i("error")
```
Performance tips:
- Prefer using case-sensitive filter over case-insensitive filter.
- Prefer moving [word filter](#word-filter), [phrase filter](#phrase-filter) and [prefix filter](#prefix-filter) in front of case-sensitive filter
when using [logical filter](#logical-filter).
- See [other performance tips](#performance-tips).
See also:
- [Word filter](#word-filter)
- [Phrase filter](#phrase-filter)
- [Exact-filter](#exact-filter)
- [Logical filter](#logical-filter)
### Sequence filter
Sometimes it is needed to find [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field)
with [words](#word) or phrases in a particular order. For example, if log messages with `error` word followed by `open file` phrase
must be found, then the following LogsQL query can be used:
```logsql
seq("error", "open file")
```
This query matches `some error: cannot open file /foo/bar` message, since the `open file` phrase goes after the `error` [word](#word).
The query doesn't match the `cannot open file: error` message, since the `open file` phrase is located in front of the `error` [word](#word).
If you need matching log messages with both `error` word and `open file` phrase, then use `error AND "open file"` query. See [these docs](#logical-filter)
for details.
By default the `seq()` filter is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Specify the needed [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the filter
in order to apply it to the given field. For example, the following query matches `event.original` field containing `(error, "open file")` sequence:
```logsql
event.original:seq(error, "open file")
```
If the field name contains special chars, which may clash with the query syntax, then it may be put into quotes in the query.
For example, the following query matches `event:original` field containing `(error, "open file")` sequence:
The query matches the following [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field), which contain either `err` or `warn` substrings:
- Prefer using `exact("some prefix"*)` instead of `re("^some prefix")`, since the [exact()](#exact-prefix-filter) works much faster than the `re()` filter.
If you need to filter log message by some field containing only numeric values, then the `range()` filter can be used.
For example, if the `request.duration` field contains the request duration in seconds, then the following LogsQL query can be used
for searching for log entries with request durations exceeding 4.2 seconds:
```logsql
request.duration:range(4.2, Inf)
```
The lower and the upper bounds of the range are excluded by default. If they must be included, then substitute the corresponding
parentheses with square brackets. For example:
-`range[1, 10)` includes `1` in the matching range
-`range(1, 10]` includes `10` in the matching range
-`range[1, 10]` includes `1` and `10` in the matching range
Note that the `range()` filter doesn't match [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
with non-numeric values alongside numeric values. For example, `range(1, 10)` doesn't match `the request took 4.2 seconds`
[log message](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field), since the `4.2` number is surrounded by other text.
Extract the numeric value from the message with `parse(_msg, "the request took <request_duration> seconds")` [transformation](#transformations)
and then apply the `range()` [post-filter](#post-filters) to the extracted `request_duration` field.
Performance tips:
- It is better to query pure numeric [field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
instead of extracting numeric field from text field via [transformations](#transformations) at query time.
- See [other performance tips](#performance-tips).
See also:
- [IPv4 range filter](#ipv4-range-filter)
- [String range filter](#string-range-filter)
- [Length range filter](#length-range-filter)
- [Logical filter](#logical-filter)
### IPv4 range filter
If you need to filter log message by some field containing only [IPv4](https://en.wikipedia.org/wiki/Internet_Protocol_version_4) addresses such as `1.2.3.4`,
then the `ipv4_range()` filter can be used. For example, the following query matches log entries with `user.ip` address in the range `[127.0.0.0 - 127.255.255.255]`:
```logsql
user.ip:ipv4_range(127.0.0.0, 127.255.255.255)
```
The `ipv4_range()` accepts also IPv4 subnetworks in [CIDR notation](https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation).
For example, the following query is equivalent to the query above:
```logsql
user.ip:ipv4_range("127.0.0.0/8")
```
If you need matching a single IPv4 address, then just put it inside `ipv4_range()`. For example, the following query matches `1.2.3.4` IP
at `user.ip` [field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model):
```logsql
user.ip:ipv4_range("1.2.3.4")
```
Note that the `ipv4_range()` doesn't match a string with IPv4 address if this string contains other text. For example, `ipv4_range("127.0.0.0/24")`
doesn't match `request from 127.0.0.1: done` [log message](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field),
since the `127.0.0.1` ip is surrounded by other text. Extract the IP from the message with `parse(_msg, "request from <ip>: done")` [transformation](#transformations)
and then apply the `ipv4_range()` [post-filter](#post-filters) to the extracted `ip` field.
- If you need searching for [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field) containing the given `X.Y.Z.Q` IPv4 address,
at least a single IPv4 address out of the given list, then `"ip1" OR "ip2" ... OR "ipN"` query can be used. See [these docs](#logical-filter) for details.
- If you need finding log entries with `ip` field in multiple ranges, then use `ip:(ipv4_range(range1) OR ipv4_range(range2) ... OR ipv4_range(rangeN))` query.
- It is better querying pure IPv4 [field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
instead of extracting IPv4 from text field via [transformations](#transformations) at query time.
- See [other performance tips](#performance-tips).
See also:
- [Range filter](#range-filter)
- [String range filter](#string-range-filter)
- [Length range filter](#length-range-filter)
- [Logical filter](#logical-filter)
### String range filter
If you need to filter log message by some field with string values in some range, then `string_range()` filter can be used.
For example, the following LogsQL query matches log entries with `user.name` field starting from `A` and `B` chars:
```logsql
user.name:string_range(A, C)
```
The `string_range()` includes the lower bound, while excluding the upper bound. This simplifies querying distinct sets of logs.
For example, the `user.name:string_range(C, E)` would match `user.name` fields, which start from `C` and `D` chars.
See also:
- [Range filter](#range-filter)
- [IPv4 range filter](#ipv4-range-filter)
- [Length range filter](#length-range-filter)
- [Logical filter](#logical-filter)
### Length range filter
If you need to filter log message by its length, then `len_range()` filter can be used.
For example, the following LogsQL query matches [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field)
with lengths in the range `[5, 10]` chars:
```logsql
len_range(5, 10)
```
This query matches the following log messages, since their length is in the requested range:
-`foobar`
-`foo bar`
This query doesn't match the following log messages:
-`foo`, since it is too short
-`foo bar baz abc`, sinc it is too long
By default the `len_range()` is applied to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field).
Put the [field name](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) in front of the `len_range()` in order to apply
the filter to the needed field. For example, the following query matches log entries with the `foo` field length in the range `[10, 20]` chars:
```logsql
foo:len_range(10, 20)
```
See also:
- [Range filter](#range-filter)
- [Logical filter](#logical-filter)
### Logical filter
Simpler LogsQL [filters](#filters) can be combined into more complex filters with the following logical operations:
-`q1 AND q2` - matches common log entries returned by both `q1` and `q2`. Arbitrary number of [filters](#filters) can be combined with `AND` operation.
For example, `error AND file AND app` matches [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field),
which simultaneously contain `error`, `file` and `app` [words](#word).
The `AND` operation is frequently used in LogsQL queries, so it is allowed to skip the `AND` word.
For example, `error file app` is equivalent to `error AND file AND app`.
-`q1 OR q2` - merges log entries returned by both `q1` and `q2`. Aribtrary number of [filters](#filters) can be combined with `OR` operation.
For example, `error OR warning OR info` matches [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field),
which contain at least one of `error`, `warning` or `info` [words](#word).
-`NOT q` - returns all the log entries except of those which match `q`. For example, `NOT info` returns all the
which do not contain `info` [word](#word). The `NOT` operation is frequently used in LogsQL queries, so it is allowed substituting `NOT` with `!` in queries.
For example, `!info` is equivalent to `NOT info`.
The `NOT` operation has the highest priority, `AND` has the middle priority and `OR` has the lowest priority.
The priority order can be changed with parentheses. For example, `NOT info OR debug` is interpreted as `(NOT info) OR debug`,
so it matches [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field),
which do not contain `info` [word](#word), while it also matches messages with `debug` word (which may contain the `info` word).
This is not what most users expect. In this case the query can be rewritten to `NOT (info OR debug)`,
which correctly returns log messages without `info` and `debug` [words](#word).
LogsQL supports arbitrary complex logical queries with arbitrary mix of `AND`, `OR` and `NOT` operations and parentheses.
By default logical filters apply to the [`_msg` field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field)
unless the inner filters explicitly specify the needed [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) via `field_name:filter` syntax.
For example, `(error OR warn) AND host.hostname:host123` is interpreted as `(_msg:error OR _msg:warn) AND host.hostname:host123`.
It is possible to specify a single [log field](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) for multiple filters
with the following syntax:
```logsql
field_name:(q1 OR q2 OR ... qN)
```
For example, `log.level:error OR log.level:warning OR log.level:info` can be substituted with the shorter query: `log.level:(error OR warning OR info)`.
Performance tips:
- VictoriaLogs executes logical operations from the left to the right, so it is recommended moving the most specific
and the fastest filters (such as [word filter](#word-filter) and [phrase filter](#phrase-filter)) to the left,
while moving less specific and the slowest filters (such as [regexp filter](#regexp-filter) and [case-insensitive filter](#case-insensitive-filter))
to the right. For example, if you need to find [log messages](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#message-field)
with the `error` word, which match some `/foo/(bar|baz)` regexp,
it is better from performance PoV to use the query `error re("/foo/(bar|baz)")` instead of `re("/foo/(bar|baz)") error`.
The most specific filter means that it matches the lowest number of log entries comparing to other filters.
- See [other performance tips](#performance-tips).
## Stream context
LogsQL will support the ability to select the given number of surrounding log lines for the selected log lines
on a [per-stream](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#stream-fields) basis.
See the [Roadmap](https://docs.victoriametrics.com/VictoriaLogs/Roadmap.html) for details.
## Transformations
It is possible to perform various transformations on the [selected log entries](#filters) at client side
LogsQL will support the following transformations for the [selected](#filters) log entries:
- Extracting the specified fields from text [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model) according to the provided pattern.
- Extracting the specified fields from JSON strings stored inside [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model).
- Extracting the specified fields from [logfmt](https://brandur.org/logfmt) strings stored
- Creating a new field from existing [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
according to the provided format.
- Creating a new field according to math calculations over existing [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model).
- Copying of the existing [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model).
- Parsing duration strings into floating-point seconds for further [stats calculations](#stats).
- Creating a boolean field with the result of arbitrary [post-filters](#post-filters) applied to the current fields.
Boolean fields may be useful for [conditional stats calculation](#stats).
- Creating an integer field with the length of the given field value. This can be useful for [stats calculations](#stats).
See the [Roadmap](https://docs.victoriametrics.com/VictoriaLogs/Roadmap.html) for details.
## Post-filters
It is possible to perform post-filtering on the [selected log entries](#filters) at client side with `grep` or similar Unix commands
LogsQL will support calculating the following stats based on the [log fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
and fields created by [transformations](#transformations):
- The number of selected logs.
- The number of non-empty values for the given field.
- The number of unique values for the given field.
- The min, max, avg, and sum for the given field.
- The median and [percentile](https://en.wikipedia.org/wiki/Percentile) for the given field.
It will be possible specifying an optional condition [filter](#post-filters) when calculating the stats.
For example, `sumIf(response_size, is_admin:true)` calculates the total response size for admins only.
It will be possible to group stats by the specified [fields](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model)
and by the specified time buckets.
See the [Roadmap](https://docs.victoriametrics.com/VictoriaLogs/Roadmap.html) for details.
If you want selecting other fields from the ingested [structured logs](https://docs.victoriametrics.com/VictoriaLogs/keyConcepts.html#data-model),
then they must be mentioned in query filters. For example, if you want selecting `log.level` field, and this field isn't mentioned in the query yet, then add
`log.level:*` [filter](#any-value-filter) filter to the end of the query.
The `field_name:*` filter doesn't return log entries with empty or missing `field_name`. If you want returning log entries
with and without the given field, then `(field_name:* OR field_name:"")` filter can be used.
See the following docs for details:
- [Any value filter](#any-value-filter)
- [Empty value filter](#empty-value-filter)
- [Logical filter](#logical-filter)
In the future LogsQL will support `| fields field1, field2, ... fieldN` syntax for selecting the listed fields.
It will also support the ability to select all the fields for the matching log entries with `| fields *` syntax.
See the [Roadmap](https://docs.victoriametrics.com/VictoriaLogs/Roadmap.html) for details.
