This behavior is expected if you have enabled project Auto Completion. It can be disabled for selected server under Advanced options.
Upcoming Gerrit version 2.12 has new "project created" event and ls-project will not be needed.

engy, I understand what you're saying, but when the OP says "continuous" – he literally means 6-7 requests every second, continuously. That is eating up ~25% CPU time on the Gerrit server.

Why would this be needed if no user is actively trying to type a project name? I don't think this should be closed as "Not a Defect", because 7 requests per second for data that hasn't changed and data that no user is actively trying to use, in my opinion at least, absolutely is a defect.

Looking at the configuration options that you screenshot above – I see the problem now... My Gerrit configuration in Jenkins was set like this:

To be clear, I did not set those values, so this must be an issue with the way the plugin upgrades its configurations?

Setting the values to 0 and 3600 as shown in your screenshot does resolve the issue! But how did it get set to 0 in the first place? And why is 0 an acceptable refresh interval?

Looks like this was caused by the fix for JENKINS-31473 – as prior to that fix (according to the description of that ticket), isSupported would have been returning true, so the project list would never be fetched, so the 0-second interval would never have had a chance to become problematic.

rsandell This is an unusually popular issue, so maybe worth taking a look at?

Problem is when upgrading gerrit-trigger from version 2.13.0 to version 2.14.0
There is missing a default value for ProjectListRefreshInterval when variable missing in serialized (old) XML configuration.

Code changed in jenkins
User: Jiří Engelthaler
Path:
src/main/java/com/sonyericsson/hudson/plugins/gerrit/trigger/GerritServer.java
src/main/java/com/sonyericsson/hudson/plugins/gerrit/trigger/config/Config.java
src/main/resources/com/sonyericsson/hudson/plugins/gerrit/trigger/GerritServer/index.jelly
src/test/java/com/sonyericsson/hudson/plugins/gerrit/trigger/config/ConfigTest.java
http://jenkins-ci.org/commit/gerrit-trigger-plugin/78f4c5c54191f04aef7a8317cc7b32bbb3650815
Log:
Fix projectListRefreshInterval zero value after upgrade from 2.13.0 to 2.14.0

[FIXED JENKINS-31800]

Code changed in jenkins
User: Robert Sandell
Path:
src/main/java/com/sonyericsson/hudson/plugins/gerrit/trigger/GerritServer.java
src/main/java/com/sonyericsson/hudson/plugins/gerrit/trigger/config/Config.java
src/main/resources/com/sonyericsson/hudson/plugins/gerrit/trigger/GerritServer/index.jelly
src/test/java/com/sonyericsson/hudson/plugins/gerrit/trigger/config/ConfigTest.java
http://jenkins-ci.org/commit/gerrit-trigger-plugin/ba1c6cb7712f4544df31cada3b4f83b181b428d7
Log:
Merge pull request #273 from engycz/JENKINS-31800

Fix projectListRefreshInterval zero value after upgrade from 2.13.0 to 2.14.0

Compare: https://github.com/jenkinsci/gerrit-trigger-plugin/compare/82faa6ef657d...ba1c6cb7712f