Remove code for collecting SplitCompletedEvent on workers

[raunaqmorarka]

Description

After #22879 SplitCompletedEvent are no longer being populated.
We already get detailed source stage metrics through io.trino.spi.eventlistener.QueryStatistics#getOperatorSummaries. These also contain histograms for scheduled and CPU time which are useful for assessing skews in processing of splits.
The collection of individual split events seems overkill and unnecessary to maintain at this point, especially with data lake connectors where we're taking about thousands of splits per query.
This PR removes support for io.trino.spi.eventlistener.EventListener#splitCompleted altogether and makes it clear that users need to rely on the information already present in io.trino.spi.eventlistener.EventListener#queryCompleted instead. Since the coordinator generates splits and and knows when they are finished, it can provide additional metrics to EventListener in future, if needed, rather than having all workers send events.

Additional context and related issues

Supercedes #26425

Release notes

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## Event listener
* Remove support for `io.trino.spi.eventlistener.EventListener#splitCompleted`. ({issue}`26436`)

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[wendigo]

This is backward-incompatible change but since these events were not published for over a year now and no one until now complained, I'm fine with removing the leftovers and recommending to use the QueryCompletedEvent as a source of this information instead.

[dain]

Seems reasonable to me

[raunaqmorarka]

This is backward-incompatible change but since these events were not published for over a year now and no one until now complained, I'm fine with removing the leftovers and recommending to use the QueryCompletedEvent as a source of this information instead.

JFYI we're not breaking SPI compatiblity yet to make the transition easier. Its marked for removal and will be fully deleted in a future release.

[wendigo]

@raunaqmorarka

[Copilot]

Pull Request Overview

This PR removes support for SplitCompletedEvent collection and event listener notifications throughout the Trino codebase. The removal is driven by the fact that split completion events are no longer being populated after a previous change, and detailed source stage metrics are already available through QueryStatistics#getOperatorSummaries. The collection of individual split events is deemed unnecessary, especially for data lake connectors that generate thousands of splits per query.

• Deprecates and removes SplitCompletedEvent, SplitStatistics, and SplitFailureInfo classes
• Removes EventListener#splitCompleted method implementation across all event listener plugins
• Eliminates SplitMonitor class and related infrastructure for tracking split completion events

Reviewed Changes

Copilot reviewed 42 out of 42 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
core/trino-spi/src/main/java/io/trino/spi/eventlistener/*.java	Deprecates split-related event classes and modifies EventListener interface
core/trino-main/src/main/java/io/trino/event/SplitMonitor.java	Removes entire SplitMonitor class
core/trino-main/src/main/java/io/trino/execution/*.java	Removes split monitoring integration from task execution
plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/*.java	Removes split completion event support from Kafka event listener
plugin/trino-http-event-listener/src/main/java/io/trino/plugin/httpquery/*.java	Removes split completion event support from HTTP event listener
testing/trino-tests/src/test/java/io/trino/execution/*.java	Removes split event testing infrastructure
docs/src/main/sphinx/admin/*.md	Updates documentation to remove split event configuration

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