Simple event listener exposing data via HTTP

[losipiuk]

Description

Additional context and related issues

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# Section
* Add event listener which exposes collected events on HTTP endpoint. ({issue}`22158`)

[hashhar]

this is not a listener. How does one get the query id in the first place to query the listener?

[findepi]

query id is not a provide thing. eg from io.trino.jdbc.TrinoResultSet#getStats

[losipiuk]

this is not a listener. How does one get the query id in the first place to query the listener?

You can list ids - for one (there is a listing endpoint) . But you may also just know it - get it from on of the clients which sent queries to the server.

[losipiuk]

@hashhar are we good with this one?

I can see how this can work but don't see much utility in this over the other mechanisms. Specially since this adds a non-trivial amount of work on the coordinator (query events are large and serialization is costly).

[losipiuk]

I can see how this can work but don't see much utility in this over the other mechanisms. Specially since this adds a non-trivial amount of work on the coordinator (query events are large and serialization is costly).

Direct usecase here is to integrate query-completion-events in benchto which we use for performance testing of Trino.

[hashhar]

Thanks for the context, that's helpful and makes sense.

[mosabua]

Where are the docs for this and how does it compare to

https://trino.io/docs/current/admin/event-listeners-http.html

Something is messed up here ..

Seems like its not really a event listener that it sends the events somewhere .. more like it just makes them available .. we need to document that somehow

[losipiuk]

Seems like its not really a event listener that it sends the events somewhere .. more like it just makes them available .. we need to document that somehow

Yeah - it listens internally on event and exposes data over http. We may document it if you think it is useful for end-users. So far intention was mostly to be able to expose query completion events to benchto performance testing framework.

[mosabua]

hm .. we added it in the release notes @martint and @colebow but I am not sure this really is an event listener in our sense in the docs .. I am also not sure if there is a user facing scenario that warrants documenting this feature, but there might well be. I am inclined to add some minimal docs and leave the release notes entry as is.

wdyt @losipiuk @martint @colebow @hashhar

[oneonestar]

Haven't tried this yet, but I saw no authentication for these endpoints.
I don't think this is user facing without auth.

[hashhar]

This is meant to be used with benchto only - not user facing. See trinodb/benchto#73

[mosabua]

This is meant to be used with benchto only - not user facing. See trinodb/benchto#73

So it should be removed from the release notes then.. since its an internal implementation detail. Right?

[hashhar]

IMO yes.

[losipiuk]

IMO yes.

fine by me too

[mosabua]

#22262