Fix event search performance and kind filter bug

[rbren]

Summary

This PR fixes critical performance issues and a bug in the events search endpoint that caused:

1. Kind filter never matching - The filter compared against full module paths instead of simple class names
2. Slow searches - Holding FIFOLock during full O(n) disk scans blocked agent execution

Key Changes

Bug Fixes

• Kind filter comparison - Changed from comparing f"{event.__class__.__module__}.{event.__class__.__name__}" to just event.__class__.__name__. Clients send simple class names like 'MessageEvent', not full module paths.

Performance Improvements

• Removed FIFOLock during search - Search now operates on a snapshot of event log length (GIL makes int reads atomic), avoiding blocking the agent runner thread
• Early exit for TIMESTAMP_DESC - DESC queries now scan from end of event log, making "last N events" queries O(limit) instead of O(n)
• O(1) cursor lookup - Uses EventLog.get_index() for pagination cursor lookup when available

Tests Added

New performance tests in test_event_service_perf.py that fail fast for slow queries:

• test_kind_filter_uses_simple_class_name - Verifies simple class names work
• test_search_with_limit_completes_quickly - Verifies early exit optimization
• test_desc_search_last_10_events_fast - Verifies DESC scan from end
• test_kind_filter_with_many_events_is_fast - Verifies kind filter performance
• test_pagination_cursor_lookup_is_fast - Verifies O(1) cursor lookup

Testing

uv run pytest tests/agent_server/test_event_service.py tests/agent_server/test_event_service_perf.py -v
# 67 passed

Relaxed Constraints

Per the issue, some constraints about the endpoint being perfectly up-to-date have been relaxed:

• Search operates on a snapshot of event count, so new events appended during search may not be included
• This is acceptable as it avoids blocking agent execution with the FIFOLock

@rbren can click here to continue refining the PR

---

Agent Server images for this PR

• GHCR package: https://github.com/OpenHands/agent-sdk/pkgs/container/agent-server

Variants & Base Images

Variant	Architectures	Base Image	Docs / Tags
java	amd64, arm64	eclipse-temurin:17-jdk	Link
python	amd64, arm64	nikolaik/python-nodejs:python3.12-nodejs22	Link
golang	amd64, arm64	golang:1.21-bookworm	Link

Pull (multi-arch manifest)

# Each variant is a multi-arch manifest supporting both amd64 and arm64
docker pull ghcr.io/openhands/agent-server:bee4fe1-python

Run

docker run -it --rm \
  -p 8000:8000 \
  --name agent-server-bee4fe1-python \
  ghcr.io/openhands/agent-server:bee4fe1-python

All tags pushed for this build

ghcr.io/openhands/agent-server:bee4fe1-golang-amd64
ghcr.io/openhands/agent-server:bee4fe1-golang_tag_1.21-bookworm-amd64
ghcr.io/openhands/agent-server:bee4fe1-golang-arm64
ghcr.io/openhands/agent-server:bee4fe1-golang_tag_1.21-bookworm-arm64
ghcr.io/openhands/agent-server:bee4fe1-java-amd64
ghcr.io/openhands/agent-server:bee4fe1-eclipse-temurin_tag_17-jdk-amd64
ghcr.io/openhands/agent-server:bee4fe1-java-arm64
ghcr.io/openhands/agent-server:bee4fe1-eclipse-temurin_tag_17-jdk-arm64
ghcr.io/openhands/agent-server:bee4fe1-python-amd64
ghcr.io/openhands/agent-server:bee4fe1-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-amd64
ghcr.io/openhands/agent-server:bee4fe1-python-arm64
ghcr.io/openhands/agent-server:bee4fe1-nikolaik_s_python-nodejs_tag_python3.12-nodejs22-arm64
ghcr.io/openhands/agent-server:bee4fe1-golang
ghcr.io/openhands/agent-server:bee4fe1-java
ghcr.io/openhands/agent-server:bee4fe1-python

About Multi-Architecture Support

• Each variant tag (e.g., bee4fe1-python) is a multi-arch manifest supporting both amd64 and arm64
• Docker automatically pulls the correct architecture for your platform
• Individual architecture tags (e.g., bee4fe1-python-amd64) are also available if needed

[github-actions]

API breakage checks (Griffe)

Result: Passed

Action log

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
openhands-agent-server/openhands/agent_server
event_service.py	348	99	71%	55–56, 74–76, 84–91, 94–97, 117, 141–142, 165–166, 185, 192, 249, 263–264, 272, 325–326, 330, 338, 341, 389–390, 398–399, 415, 417, 421–423, 427, 436–437, 439, 443, 449, 451, 459–464, 600, 602–603, 607, 621–623, 625, 629–632, 636–639, 647–650, 669–670, 672–679, 681–682, 691–692, 694–695, 702–703, 705–706, 710, 716, 733–734
TOTAL	18778	8588	54%

[rbren]

@OpenHands fix the failing gh actions

[openhands-ai]

I'm on it! rbren can track my progress at all-hands.dev

[openhands-ai]

Summary

I fixed the failing GitHub Actions pre-commit check on PR #2174.

Issue

The Pre-commit checks/pre-commit workflow was failing due to a Ruff formatting violation in event_service.py.

Fix Applied

Changed a multi-line logger.debug() call to a single line:

-                logger.debug(
-                    "Lock held during subscribe, sending minimal state update"
-                )
+                logger.debug("Lock held during subscribe, sending minimal state update")

Verification

• ✅ Ran pre-commit locally - all checks passed
• ✅ Change is minimal and directly addresses the formatting issue
• ✅ Committed with proper co-author attribution
• ✅ Already pushed to fix-event-search-perf branch

The GitHub Actions should now pass with this formatting fix.