Splunk Search

Join or Subsearch performance

MaryvonneMB
Path Finder

Hi all,

I have a performance question about "join" and "subsearch".
Even join is a ressource-guzzler command I saw that sometimes it works better than a subsearch:

for example:

Query A =>  index=my_index [search index=other_one earliest=-1d@d|fields field1 |dedup field1|table field1]
Query B => index=my_index |join type=inner max=1 field1 [search index=other_index earliest=-1d@d |fields field1 |dedup field1|table field1]

in "my_index" I have about 20 millions of datas. in "other_index" + earliest=-1d@d I have about 80 000 datas. In this case the query A is faster than query B.
But if i have more than 300 000 datas in "other_index" + earliest=-1d@d, then query B is faster query A.

Does anyone have an explanation?

Thanks 🙂

0 Karma

adonio
Ultra Champion

try this:

Query A =>  earliest=-2d@d latest=-1d@d index=my_index [search index=other_one earliest=-1d@d|fields field1 |dedup field1|table field1]
 Query B => earliest=-2d@d latest=-1d@d index=my_index |join type=inner max=1 field1 [search index=other_index earliest=-1d@d |fields field1 |dedup field1|table field1]

is there still a difference?

0 Karma
Got questions? Get answers!

Join the Splunk Community Slack to learn, troubleshoot, and make connections with fellow Splunk practitioners in real time!

Meet up IRL or virtually!

Join Splunk User Groups to connect and learn in-person by region or remotely by topic or industry.

Get Updates on the Splunk Community!

Make your Splunk investment work harder with Optimization Advisor

Value Insights brings usage evidence and practical recommendations together to help customers make more ...

How Splunk AI Assistant Is Transforming Investigations: Insights from .conf26

At .conf26 in Denver, I spent much of my time in conversation with Splunk customers about Splunk AI Assistant. ...

Make Your Machine Data AI-Ready in Splunk

Every team is getting ready for AI agents.   Thursday, November 12, 2026  |  11AM  PST / 2PM EST   ...