Port PR from PBS-Go: TMax: Add default host config

[cross-repo-issue-creation[bot]]

A PR was merged over on PBS-Go

• https://github.com/prebid/prebid-server/pull/4430
• timestamp: 2025-07-17T13:34:19Z

[AntoxaAntoxic]

Hi @Net-burst

This is quite interesting:

1. I can't find any open-source issue referred to that, and according to the description of the PR it looks like a bug on the Go side where they probably never set a tmax if there is no the stored request where they can take out a default timeout
2. On the Java we have a bunch of auction.biddertmax properties which set min and max timeout for the auction and they're mandatory, so we always limit it to auction.biddertmax.max
3. Now on the Go side it looks like a new feature since they introduced a new property for that, so what should we do? I guess nothing

What do you think?

[bsardo]

@AntoxaAntoxic sorry there isn't an issue for this but the PR was discussed at the last PMC. This is a new feature. PBS-Go previously only allowed setting the default tmax via the default stored request. Now it can be set directly on the host config. We made this an option for anyone who has no other use for the default stored request so they can bypass the performance hit associated with merging a default stored request with a request-referenced stored request.

It should also be noted that if the tmax included in the original request is 0 or undefined the configured default will be used.

[AntoxaAntoxic]

@bsardo thank you for the clarifications

The thing is the PBS Java has the properties that allows to set the tmax for the auction. It's a little bit hard to iterate over all the previous decision making, but I can say for sure:

1. The PBS Java had a property called auction.max-timeout-ms which did the same the tmax_default does in the PBS Go now.
2. And with the following PRs that property has been deprecated and eventually removed since new auction.biddertmax properties have been added: https://github.com/prebid/prebid-server-java/pull/2113 and https://github.com/prebid/prebid-server-java/pull/3158

At least for me it looks like the PBS Java has already made some evolutionary steps in terms of tmax-related logic.

@Net-burst @bsardo I suppose eventually the Go and Java version must be in sync feature-wise. What should we do then?