Hi!
I work on the Kafka Java client and I was not familiar with the concept of
plugin discovery, but found a writeup here:
https://kafka.apache.org/documentation/#connect_plugindiscovery
>From reading through that, plugin discovery looks like a Connect feature.
>Unfortunately, I'm not familiar with that area, so I can't provide any
>immediate advice :(
Are you seeing this slow behavior when using Connect, or do you see it when
using the AdminClient, Consumer, and/or Producer clients?
I'm sure the developers working on Connect would like to know about this
performance behavior. Can you provide this information in a bug report at
https://issues.apache.org/jira? If so, please use the Jira "Component" value of
"connect" so that the developers working in that area will be more likely to
see the issue.
Thanks,
Kirk
On Mon, Jul 28, 2025, at 12:10 AM, Love Almgren wrote:
> Hello Kafka devs,
>
> We’re in the process of upgrading our Kafka clients from version 3.5.1 to
> 4.0.0, and have observed a significant increase in startup time related to
> plugin loading.
>
> In version 3.5.1, plugin discovery completed in 30-40 seconds. After
> upgrading to 4.0.0, the same step takes over 5 minutes. We also tested
> version 3.9.0, where the delay was still 40 seconds.
>
> We were able to work around this issue by explicitly setting:
>
> plugin.discovery = service_load
>
> This brought the startup time back to expected levels. Still, we’d like to
> better understand:
>
> 1. What might be causing the longer discovery times in newer versions?
> 2. Is this expected behavior, or might it be a regression?
> 3. Are there any risks to relying on service_load for plugin discovery?
>
> Any insights or suggestions would be greatly appreciated.
> Thanks in advance,
> Love Almgren
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