← Extractions

Toolbelt of a Seasoned Bug Hunter — debugging a Rails reload slowdown

Damir Zekić's wroclove.rb 2018 talk recounts an 'Odyssey' of diagnosing a progressively slowing Rails test-reload loop. He walks through reproducing the bug, using git bisect and a custom linear-search script, investigating memory leaks with heap dumps (heapy), rendering flame graphs, digging into Rails' routing code and Ruby's undef_method in C, and ultimately tracing the root cause to the monolith/granite framework mounting controllers at Spring boot time.

Model

claude-opus-4-7

Ingestion

97bc0a8f

Input tokens

100,629

fresh: 47,005
cached: 44,307
cache write: 9,317

Output tokens

8,847

Duration

128.4s

Roundtrips

Tool calls

Cost

$0.00

Nodes/edges extracted

21 / 38

Read set (nodes/edges)

72 / 2

Nodes (21)

update Damir Zekić person

attrs (empty) → {"role" => "Ruby programmer"}

description Conference speaker. → Conference speaker at wroclove.rb 2018. Remote Ruby programmer who enjoys pair programming with his cat Midori. Worke...

short_description Conference speaker. → Ruby developer and conference speaker; worked on the monolith/granite business-actions framework.

update Toolbelt of a Seasoned Bug Hunter talk

description Talk at wroclove.rb 2018. → Damir Zekić's wroclove.rb 2018 talk subtitled '2016: A Debugging Odyssey in Six Chapters with an Epilogue'. Recounts ...

short_description Talk at wroclove.rb 2018. → Story-driven talk on advanced debugging tools applied to a Rails reload slowdown.

update wroclove.rb 2018 event

No changes recorded.

create Spring tool

kind (empty) → tool

name (empty) → Spring

slug (empty) → spring

attrs (empty) → {"category" => "library"}

description (empty) → Rails preloader gem that loads a Rails application into memory once and forks copies for each test run, console, or c...

short_description (empty) → Rails application preloader that keeps the app in memory between commands.

create Guard tool

kind (empty) → tool

name (empty) → Guard

slug (empty) → guard

attrs (empty) → {"category" => "library"}

description (empty) → Ruby tool that watches files and automatically re-runs tests (or other tasks) when files change. Used together with S...

short_description (empty) → Ruby file-watcher that reruns tests on file change.

create git bisect tool

kind (empty) → tool

name (empty) → git bisect

slug (empty) → git-bisect

attrs (empty) → {"category" => "tool"}

description (empty) → Git subcommand that binary-searches commit history between a known-good and a known-bad commit, running a user script...

short_description (empty) → Git command performing binary search through history to find a bad commit.

create find-slow script tool

kind (empty) → tool

name (empty) → find-slow script

slug (empty) → find-slow-script

attrs (empty) → {"category" => "tool"}

description (empty) → Ad-hoc Ruby script the speaker wrote to extend git bisect when no known-good commit existed: checks out each previous...

short_description (empty) → Custom Ruby script that linearly walks git history to find a non-slow commit.

create heapy tool

kind (empty) → tool

name (empty) → heapy

slug (empty) → heapy

attrs (empty) → {"category" => "library"}

description (empty) → Ruby gem installed as a command-line tool that parses ObjectSpace heap-dump JSON files and summarizes how many object...

short_description (empty) → Ruby gem for analyzing heap dumps produced by ObjectSpace.

create ObjectSpace heap dumps concept

kind (empty) → concept

name (empty) → ObjectSpace heap dumps

slug (empty) → objectspace-heap-dumps

attrs (empty) → {"category" => "practice"}

description (empty) → Ruby's built-in facility (ObjectSpace + allocation tracing) to dump every live object to a file where each line is a ...

short_description (empty) → Built-in Ruby mechanism to snapshot all live objects to a JSON-lines file.

create Flame Graphs concept

kind (empty) → concept

name (empty) → Flame Graphs

slug (empty) → flame-graphs

attrs (empty) → {"category" => "practice"}

description (empty) → Visualization technique where the x-axis represents aggregated stack frames and the y-axis represents call depth, let...

short_description (empty) → Stacked visualization of sampled call-stack frames showing where time is spent.

create monolith framework project

kind (empty) → project

name (empty) → monolith framework

slug (empty) → monolith-framework

attrs (empty) → {"status" => "superseded", "license" => "closed-source"}

description (empty) → Internal 'business-action framework' built on top of Rails that let developers encapsulate commands/operations with v...

short_description (empty) → Arkency's in-house business-actions framework for monolithic Rails apps (predecessor of granite).

create granite project

kind (empty) → project

name (empty) → granite

slug (empty) → granite

attrs (empty) → {"status" => "active", "license" => "open-source", "repository" => "github.com/.../granite"}

description (empty) → Open-source successor to the monolith framework, announced publicly for the first time during this talk. A business-a...

short_description (empty) → Open-source business-actions architecture gem for Rails apps.

create Rails RouteSet clear concept

kind (empty) → concept

name (empty) → Rails RouteSet clear

slug (empty) → rails-routeset-clear

attrs (empty) → {"category" => "architecture"}

description (empty) → ActionDispatch::Routing::RouteSet#clear iterates over the _path_helpers and _url_helpers modules and calls undef_meth...

short_description (empty) → Rails routing internal that undef_methods all URL/path helpers on every reload.

create Ruby undef_method performance concept

kind (empty) → concept

name (empty) → Ruby undef_method performance

slug (empty) → ruby-undef_method-performance

attrs (empty) → {"category" => "architecture"}

description (empty) → Benchmark shown in the talk: defining and undef-ing methods across N modules-included-in-objects is far from linear i...

short_description (empty) → undef_method scales super-linearly and spends half its time clearing the method cache.

create Ruby memory retention behavior concept

kind (empty) → concept

name (empty) → Ruby memory retention behavior

slug (empty) → ruby-memory-retention-behavior

attrs (empty) → {"category" => "architecture"}

description (empty) → Ruby's garbage collector reclaims objects inside the Ruby heap but does not shrink the process by returning memory to...

short_description (empty) → Ruby's GC frees objects but does not return freed heap pages to the OS.

create DescendantsTracker concept

kind (empty) → concept

name (empty) → DescendantsTracker

slug (empty) → descendantstracker

attrs (empty) → {"category" => "architecture"}

description (empty) → ActiveSupport::DescendantsTracker is mixed into every class in a Rails app and stores, in a class-level class-variabl...

short_description (empty) → ActiveSupport module that keeps a hash of every class and its subclasses.

create Know thy app takeaway

kind (empty) → takeaway

name (empty) → Know thy app

slug (empty) → know-thy-app

attrs (empty) → {"type" => "lesson-learned"}

description (empty) → The closing lesson of the talk: debugging subtle, long-running performance bugs requires knowing not just your own co...

short_description (empty) → Know your code, your framework, your libraries, and the language — otherwise bugs like this are inevitable.

create Don't create controllers at Rails boot time takeaway

kind (empty) → takeaway

name (empty) → Don't create controllers at Rails boot time

slug (empty) → don-t-create-controllers-at-rails-boot-time

attrs (empty) → {"type" => "lesson-learned"}

description (empty) → Concrete lesson from the monolith debugging: mounting business-action objects (which generated controllers) onto rout...

short_description (empty) → Creating controllers before Spring forks makes them immortal across reloads.

create Use Ruby to debug Ruby takeaway

kind (empty) → takeaway

name (empty) → Use Ruby to debug Ruby

slug (empty) → use-ruby-to-debug-ruby

attrs (empty) → {"type" => "recommendation"}

description (empty) → Takeaway repeated throughout the talk: the speaker leaned on small Ruby scripts (linear-search across git history, di...

short_description (empty) → When off-the-shelf tools don't fit, writing a small Ruby script is often the fastest diagnostic tool.

create Stable commits enable bisect takeaway

kind (empty) → takeaway

name (empty) → Stable commits enable bisect

slug (empty) → stable-commits-enable-bisect

attrs (empty) → {"type" => "recommendation"}

description (empty) → Practical recommendation: to use git bisect effectively, every commit on the main history must be independently build...

short_description (empty) → Keep every commit green so git bisect (and similar tooling) remains usable.

create Was debugging dev-environment performance worth it vs. ditching Spring/Guard? question

kind (empty) → question

name (empty) → Was debugging dev-environment performance worth it vs. ditching Spring/Guard?

slug (empty) → was-debugging-dev-environment-performance-worth-it-vs-ditching-spring-guard

attrs (empty) → {"answer_summary" => "Yes — with 50–200 developers running tests daily, Spring's speedup over the first few runs was ...

description (empty) → Audience Q&A question asking whether the multi-week debugging effort was worth it versus simply removing Spring or Gu...

short_description (empty) → Q&A: was the long debugging investment justified instead of dropping Spring/Guard?

Edges (38)

update Damir Zekić → authored → Toolbelt of a Seasoned Bug Hunter

context (empty) → Delivered the talk at wroclove.rb 2018.

update Toolbelt of a Seasoned Bug Hunter → presented_at → wroclove.rb 2018

context (empty) → Talk given at wroclove.rb 2018 on 2018-03-16.

create Damir Zekić → attended → wroclove.rb 2018

context (empty) → Spoke at the conference.

relation (empty) → attended

source_node_id (empty) → 93c1df89-64bd-4e49-b555-d6b618dd6f35

target_node_id (empty) → 9243ef2c-21bb-4f23-b450-9ecd87882dfe

create Damir Zekić → works_on → monolith framework

attrs (empty) → {"role" => "contributor"}

context (empty) → Worked on the in-house business-actions framework that was the subject of the debugging story.

relation (empty) → works_on

source_node_id (empty) → 93c1df89-64bd-4e49-b555-d6b618dd6f35

target_node_id (empty) → 427481c5-23b4-45bf-a5d8-ce6dc5917c20

create Damir Zekić → works_on → granite

attrs (empty) → {"role" => "contributor"}

context (empty) → Announces granite at the talk as the open-sourced successor to monolith.

relation (empty) → works_on

source_node_id (empty) → 93c1df89-64bd-4e49-b555-d6b618dd6f35

target_node_id (empty) → 25015725-35e3-4aec-ae7a-cc0639ce7059

create Damir Zekić → uses → Spring

context (empty) → Describes using Spring in the team's development workflow.

relation (empty) → uses

source_node_id (empty) → 93c1df89-64bd-4e49-b555-d6b618dd6f35

target_node_id (empty) → a182d808-d06a-4ac8-b5ca-97e0dacd1d0e

create Damir Zekić → uses → Guard

context (empty) → Describes using Guard to automatically run tests on file changes.

relation (empty) → uses

source_node_id (empty) → 93c1df89-64bd-4e49-b555-d6b618dd6f35

target_node_id (empty) → 120a09f1-2974-46e8-899f-5b2c40554e78

create Toolbelt of a Seasoned Bug Hunter → about → Spring

context (empty) → Spring's preloader/fork model is central to the reload-slowdown bug investigated.

relation (empty) → about