epgsql/pooler

Pooler is an Erlang library for managing dynamic connection pools of OTP behaviors. It provides a multi-pool architecture where each pool is independently supervised and serviced by its own gen\_server, preventing cross-pool contention and failure cascades. The system supports asynchronous member lifecycle management, group-based load balancing, and configurable connection recycling. It includes a benchmarking suite for performance testing and configuration examples for setting up multiple pools.

A new benchmarking suite has been added to the 'bench' directory, providing a test rig for performance testing the pooler library using basho\_bench. This includes a Makefile for building and running tests, configuration files (pooler.config, rebar.config), and Erlang modules (consumer, member, pooler\_driver) that simulate workloads and manage pool members. The suite allows users to run configurable load tests against the pooler implementation.

bench · high confidence

Added configuration files for the pooler application, providing example setups for managing connection pools. The new files, demo.config and pooler-example.config, define two pools (pool1 and pool2) with specific start functions and connection limits, serving as a reference for users configuring the pooler system.

config · high confidence

The application has been renamed from pidq to pooler, including the main application module (pooler\_app) and the root supervisor (pooler\_sup). The old pidq\_sup supervisor has been removed. The new structure introduces a multi-level supervisor hierarchy: pooler\_sup manages pooler\_starter\_sup and individual pool supervisors (pooler\_pool\_sup), each of which manages member supervisors (pooler\_pooled\_worker\_sup) and the pooler\_starter for async member lifecycle. This refactoring supports dynamic pool creation, hot upgrades, and better separation of concerns for pool management.

src · high confidence

The library has been refactored from a single shared pool to a multi-pool architecture where each pool is serviced by its own gen\_server with an independent supervision tree, preventing cross-pool contention and failure cascades. Member creation and removal are now asynchronous and parallelized, keeping the pool server responsive during slow worker startups. The API has changed: pool names are now atoms, the old take\_pid/take\_member/0 functions are removed, and new group-based load balancing is available via pooler:take\_group\_member/1. Additionally, the project has migrated to Rebar3, added an Apache 2.0 license, and introduced configurable culling of stale members and proactive TTL-based connection recycling.

(repo-wide) · high confidence

Added new benchmark tests in test/bench\_take\_return.erl to measure take/return performance across various pool sizes and configurations, including FIFO dispatch order and TTL-based recycling scenarios. Added property-based tests in test/prop\_pooler.erl using the 'proper' library to verify pool behavior under randomized conditions. Added performance tests in test/pooler\_perf\_test.erl to validate concurrent worker behavior. Supporting test infrastructure includes error\_logger\_mon.erl for log monitoring, fake\_metrics.erl for metrics instrumentation testing, pooled\_gs.erl as a testable gen\_server member, and hotupgrade\_test.sh for release hot code upgrade validation.

test · high confidence

New documentation files have been added to the project. doc/dev-notes.org provides detailed implementation notes for the pooler application, covering the supervision tree, state management, member culling, and pool management specifications. Additionally, doc/overview.edoc was added to provide a high-level overview of the pooler OTP application and its usage for managing pools of OTP behaviors.

doc · high confidence

Written by watchdog.canine.dev from the codebase's own history, inside the signed delivery this page is composed from.

• CAI 67 → 67 (-0.5)
• Rubric changed (rubric-2026.08.19 → rubric-2026.09.15) — scores are not directly comparable.

• Code Health 95 → 96 (+0.8)
• Architecture 100 → 100 (+0.0)
• Maturity 48 → 53 (+4.6)
• Readiness 74 → 64 (-9.7)
• Security 85 → 84 (-1.8)
• Event Sourcing 100 → 100 (+0.0)

• Coverage not included — suite not readable by the collector
• Dependency hygiene not measured — dependency manifest found but not parsed for hygiene
• No exposed public API
• Off-boarding risk: anonymized user #1
• Test reliability not included
• TooManyMethods: pooler (src/pooler.erl)
• complexity unreadable for .erl — churn × complexity hotspots could not be measured

• Coverage not measured — no coverage collector is wired up
• Dependency hygiene PARTLY measured — rebar3 pinning read, dependency currency not (no rebar.lock-pinned Hex declaration to grade)
• Documentation: no usage examples (bench/README.md)
• Duplicated block (5 lines × 2) (src/pooler.erl)
• Duplicated block (5 lines × 2) (src/pooler.erl)
• Duplicated block (8–9 lines × 2) (bench/src/pooler_driver.erl)
• FixmeComment (src/pooler.erl)
• FixmeComment (test/pooler_tests.erl)
• FixmeComment (test/pooler_tests.erl)
• Floating source dependency: basho_bench
• Floating source dependency: pooler
• High: security finding (details withheld)
• High: security finding (details withheld)
• Hotspot: src/pooler.erl (src/pooler.erl)
• Medium: security finding (details withheld)
• Off-boarding risk: anonymized user #1
• TodoComment (src/pooler.erl)
• TodoComment (src/pooler_app.erl)
• Workflow token permissions not restricted
• pooler.mk_rec_action (cyclomatic 35) (src/pooler.erl)

Written by watchdog.canine.dev from the codebase's own history, inside the signed delivery this page is composed from.

epgsql/pooler was measured the same way every project in this corpus was: the same rubric, at a pinned commit, with the result published in full. Point a surveyor at a repository you know and see whether you agree with it.