Joins two LogScale searches. When joining two searches, you need
to define the keys/fields that are used to match up results. This is done
using the field=name or
field=[name,name,...] parameter.
If you want to join on a single field name, you can use the syntax
fieldName =~ join(...)to specify the field.
If the subquery has a different field that you want to match against, then
use the parameter
key=[name1,name2,...] to
designate the names of keys inside the subquery. The value of keys
defaults to the value of field.
join() is a filter function which in the default
mode=inner lets the events
through that match on the join keys. If you specify
mode=left then events that do
not match the join key(s) will also be let through.
If you specify include=[field, field,
...] then those fields are extracted from the result of the
subquery, and added to matching events. For events in the subquery that do
not have one or more of the named include fields, the output will be the
empty string.
Using the parameter max=N (which
defaults to max=1) you can specify how
many rows/events are picked up in the subquery. If a subquery has multiple
events with the same join key, then up to max rows are emitted.
You can use the parameters start
and end to specify an
alternative time interval for the query. The parameter view can be used to
direct the subquery to run in a different repository or view, and the
live=true|false parameter can be
used to control if the subquery runs as a live query. The defaults for all
these parameters are inherited from the primary query containing the
join(...) usage.
The join() function also has a concept of a maximum
size of the resultset of the inner query specified with the
limit=100000 parameter.
Warning
The join() function does two passes over the data
and should not be used as part of a live query. The two passes consist
of the primary query and the subquery; as two separate queries the sets
of data on which they are executed may be different leading to
inconsistent results.
When used in a live query, the query will be run in a repeated mode instead, in which the server chooses the repetition interval based on the resources used by the function.
This can impact the liveness of the query, in that long-running repeated queries can be throttled, and thus be less live than expected.
| Parameter | Type | Required | Default Value | Description |
|---|---|---|---|---|
end | string | optional[a] | End of main query | Specifies either the timestamp relative to the main query's end (for example, end=2h will be two hours before the end of the main query) or an absolute timestamp in milliseconds since UTC. |
field | array of strings | required | Specifies which field in the event (log line) must match the given column value. | |
include | array of strings | optional[a] | none | Specifies columns to include from the subquery. |
key | array of strings | optional[a] | Specifies which fields of the subquery to join on. Defaults to the value of the field parameter. | |
limit | number | optional[a] | 100000 | Specifies the maximum number of rows in the subquery. |
| Minimum | 1 | |||
| Maximum | 200000 | |||
live | boolean | optional[a] | Same as main query | Control if the subquery runs as live or static query. |
max | integer | optional[a] | 1 | Maximum number of events found in subquery if several share join key. |
mode | string | optional[a] | inner | Specifies the mode (inner or left) of the join. |
| Valid Values | ||||
inner | Perform an inner join; return only results that match in both queries | |||
left | Perform a left join, all values from the parent query are included, matched to any corresponding events in subquery. | |||
query[b] | function | required | The subquery to execute producing the values to join with. | |
repo | string | optional[a] | Repo of main query | Specify which view/repo in which to perform the subquery. |
start | string | optional[a] | Start of main query | Specifies either the timestamp relative to the main query's end (for example, start=2h will be two hours before the end of the main query) or an absolute timestamp in milliseconds since UTC. |
view | string | optional[a] | View of main query | Specify which view/repo in which to perform the subquery. |
[a] Optional parameters use their default value unless explicitly set. | ||||
Hide omitted argument names for this function
Omitted Argument NamesThe argument name for
querycan be omitted; the following forms of this function are equivalent:logscale Syntaxjoin("value",field=["value"])and:
logscale Syntaxjoin(query="value",field=["value"])These examples show basic structure only.
Hide negatable operation for this function
Negatable Function OperationThis function is negatable, implying the inverse of the result. For example:
logscale Syntax!join()Or:
logscale Syntaxnot join()For more information, see Negating the Result of Filter Functions.
Find some examples at join() Syntax section.