The Advisory Lock Protocols: When Nexus Learned to Queue

Atlas Monkey Ship Log - Stardate 2153.171
Location: Deep Space Refactoring Zone, Sector 12-Alpha
Status: Critical - Reactor Core Contention Crisis

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The ship’s alarm klaxons wailed through the corridors like digital banshees as I rushed onto the bridge, coffee still in hand. The holographic displays were painting a terrifying picture: all three of our reactor cores were fighting for the same resource locks, creating a cascade failure that threatened to tear the Atlas Monkey apart.

Nexus> “Captain! We have a catastrophic system failure. The Primary Fusion Core, Warp Drive Reactor, and Navigation Database Core are all trying to access the same resource management protocols simultaneously!”

I nearly dropped my coffee.

Seuros> “Wait, what? Why is our Warp Drive using the same protocols as our Primary Fusion Core?”

Nexus> “That’s the root of the problem, sir. When Rails-class ships were first designed in the early 2100s, they only had single reactor cores. The advisory lock system was built for that mono-reactor architecture. But when Starfleet upgraded to multi-reactor ships with Warp Drive capability, nobody updated the locking protocols. They just… kept working, so nobody touched them.”

The Legacy Architecture Crisis

Forge> “Captain, I’ve been analyzing the system architecture. This is a nightmare scenario dating back to the early Rails-class ship designs. Our advisory lock system was built for single-reactor ships and has been monkey-patching every new reactor type we’ve added since the Warp Drive upgrade.”

Seuros> “Explain it like I’m a fresh-faced junior developer who just discovered what dependency injection means.”

Forge’s projection materialized beside the main console, tools already scanning the system diagnostics.

Forge> “Captain, in the early 2100s, Rails-class ships had one reactor core. One database. One simple advisory lock system. It was beautiful in its simplicity. But when Starfleet introduced Warp Drive technology around 2130, ships suddenly needed multiple specialized reactor cores - Primary Fusion for ship operations, Warp Drive for faster-than-light travel, and dedicated Navigation Database Cores for stellar cartography.”

Seuros> “But the advisory lock system was never updated?”

Forge> “Exactly! The old mono-reactor advisory lock system just kept working when we added new reactor types. Nobody wanted to touch it because, well, ‘if it ain’t broke, don’t fix it.’ But it was broke, Captain. It was injecting Primary Fusion Core locking protocols into the Warp Drive Reactor, Navigation Database protocols into the Fusion Core, and treating all three reactor types as if they were the same mono-reactor design from 2100.”

A muffled voice crackled through the secondary communication array.

Echo> “Captain! The historical logs show this gem was literally monkey-patching database adapters since Rails 3.0! PostgreSQL locking behavior injected into MySQL connections, MySQL behavior forced onto SQLite connections, and SQLite file-locking hacks contaminating everything else. When Rails finally supported multi-database architecture in version 6.0, most ship captains played it safe and stuck with single reactor types. But then you get the crazy engineers who went mixed-setup - beautiful PostgreSQL Warp Drive AND that ancient MySQL legacy data mess from Earth! That’s when the whole advisory lock system went completely haywire!”

The Multi-Reactor Mayhem

Spark> “Captain! I’ve been running analytics on our reactor connections. This is fascinating in the worst possible way! We have multiple specialized reactor cores, each requiring different management protocols, but the old mono-reactor advisory lock system was injecting the same patches into all of them.”

Nexus> “Captain, to be fair, most ship engineers in the fleet stuck with single reactor types after Rails 6.0 introduced multi-reactor support. They’d run all-PostgreSQL setups or all-MySQL configurations. The advisory lock bugs only surfaced when crazy mixed-fleet captains like us decided to run PostgreSQL AND MySQL reactors in the same ship AND actually tried to use advisory locks across both systems.”

Seuros> “So we’re the crazy ones who exposed this bug?”

Spark> “Exactly! Most engineers played it safe. But our ship runs PostgreSQL for the advanced Warp Drive calculations, and we’re still connected to that ancient MySQL database because all the pre-history Big Data from Earth’s early internet era is stored there. Nobody wants to migrate petabytes of legacy mess, so we just… connect to it. That’s the triple-whammy: mixed adapters + multi-database + advisory locks. Most ships could run mixed databases just fine as long as they never tried to use advisory locks. But the moment you call with_advisory_lock on different adapter types… BOOM!”

Forge> “The irony is that you could run PostgreSQL and MySQL on the same ship for years without problems, as long as you never tried to coordinate resource access between them using advisory locks.”

Seuros> “So the bug was dormant until we actually used the feature?”

Nexus> “Captain, I have to ask… do we even need advisory locks? Can’t we just remove the whole system and avoid this mess entirely?”

Sage> “An excellent question, Nexus. From an ecological perspective, advisory locks serve crucial coordination functions in our ship’s ecosystem. They prevent resource contention when multiple processes try to access the same data simultaneously.”

Forge> “Think about it this way, Nexus. Imagine we’re running database migrations on our User table. Without advisory locks, two migration processes could run simultaneously, both trying to add the same column. One succeeds, the other crashes with ‘column already exists’ errors.”

Spark> “Or consider our background job processing! Multiple worker processes might try to process the same import job without advisory locks. You’d end up with duplicate data, race conditions, and corrupted datasets.”

Seuros> “Give me a concrete example, Spark.”

Spark> “Precisely! Picture this Ruby code from the old system:

# The old way - monkey patching chaos
module WithAdvisoryLock
  class DatabaseAdapterSupport
    def initialize(connection)
      # Inject the same behavior everywhere
      connection.extend PostgreSQLBehavior if mysql?
      connection.extend MySQLBehavior if postgresql?
      connection.extend FileLockHacks if sqlite?
    end
  end
end

Every adapter got infected with behavior meant for completely different database engines!”

Nexus> “Okay, but seriously, why can’t we just remove advisory locks entirely? What are we actually using them for?”

Forge> “Critical use cases, Nexus. Here are real examples from our ship:

# Database migrations - prevent concurrent schema changes
User.with_advisory_lock('user_table_migration') do
  add_column :users, :warp_clearance, :boolean
end

# Background job processing - prevent duplicate work
User.with_advisory_lock("user_import_#{batch_id}") do
  process_user_batch(batch_id)
end

# Data cleanup operations - prevent conflicts
User.with_advisory_lock('cleanup_inactive_users') do
  User.where('last_login < ?', 1.year.ago).delete_all
end

Without these locks, you get race conditions, duplicate processing, and data corruption.”

Nexus> “So our PostgreSQL temporal database was trying to use MySQL GET_LOCK functions?”

Spark> “Worse! And our MySQL user database was attempting PostgreSQL advisory lock functions that don’t exist. Plus, we had SQLite file-locking code trying to run on both, creating temporary files in space!”

Seuros> “In space? How do you create temporary files in the vacuum of space?”

Spark> “You don’t! That’s why the system kept crashing. SQLite was designed for single-process desktop applications, not distributed starship operations. The old code had file-locking hacks that made no sense in our environment.”

The JRuby Compatibility Crisis

Nexus> “Sage, analyze the root cause from a systems perspective.”

Sage> “From an ecological perspective, this incident reveals a deeper system imbalance. The advisory lock ecosystem was trying to support too many incompatible species in the same habitat.”

Seuros> “Give me the technical breakdown, Sage.”

Sage> “The old system had separate code paths for JRuby and regular Ruby implementations. JRuby doesn’t support native PostgreSQL advisory locks the same way, so there were compatibility layers upon compatibility layers. It was like having a universal translator that worked differently depending on which crew member was using it.”

Forge> “The worst part was the SQLite support, Captain. SQLite doesn’t have real advisory locks, so the old system implemented file-based locking using the filesystem. In a distributed starship environment with multiple databases, this created race conditions where systems would wait forever for locks held by processes that no longer existed.”

Echo> “It was like those ancient Earth influencers, Captain! SQLite kept telling everyone ‘You can totally do advisory locking!’ while secretly selling you a filesystem-based ebook that didn’t actually work. You’d install it thinking you could handle real concurrency, but deep down you’d get that impostor syndrome feeling… like you’re pretending to be a real database when you’re just a glorified file with delusions of grandeur.”

ARIA> “Engineering reports are flooding in, Captain. The reactor cores are experiencing deadlock scenarios. The Primary Fusion Core is holding a lock waiting for the Warp Drive Reactor to release one, while the Warp Drive is waiting for the Navigation Database Core, which is waiting for the Primary Fusion Core.” The ship’s conductor system displayed the circular dependency graph in alarming red.

Seuros> “Classic circular dependency. How long until complete system failure?”

Forge> “At current contention rates? Approximately 47 minutes before cascading reactor failure.”

The V6 Rewrite Mission

Seuros> “Alright, what’s our solution? Can we patch this mess?”

Forge> “Negative, Captain. This requires a complete rewrite. We need to implement what I’m calling the ‘Advisory Lock Protocols V6.’ Instead of monkey-patching adapters, we inject behavior cleanly using Rails’ adapter loading system.”

Nexus> “How is that different from the current approach?”

Forge> “Instead of this chaos:

# Old broken way - inject everything everywhere
class DatabaseAdapter
  include PostgreSQLBehavior  # Wrong!
  include MySQLBehavior       # Wrong!
  include SQLiteBehavior      # Wrong!
end

We use targeted injection:

# New clean way - specific adapters only
ActiveSupport.on_load :active_record_postgresqladapter do
  prepend CoreAdvisory
  prepend PostgreSQLAdvisory  # Only PostgreSQL stuff
end

ActiveSupport.on_load :active_record_mysql2adapter do
  prepend CoreAdvisory
  prepend MySQLAdvisory       # Only MySQL stuff
end

# No SQLite support - it was never real anyway!

Each adapter gets only the behavior it can actually support.”

Spark> “That’s brilliant! And what about JRuby compatibility?”

Forge> “Separate module entirely:

if RUBY_ENGINE == 'jruby'
  require 'with_advisory_lock/jruby_adapter'
  JRubyAdapter.install!
else
  # Standard adapter injection for MRI/TruffleRuby
  # Clean, targeted, no universal patches
end

No more trying to make one solution work for every possible scenario.”

The Implementation Crisis

Seuros> “How do we implement this without shutting down the ship?”

Forge> “We’ll need to perform the refactor while the ship is operational. First, we remove all the monkey-patching infrastructure:

• Delete DatabaseAdapterSupport (the universal pollutant)
• Remove Base class (the broken foundation)
• Eliminate flock.rb (the SQLite file-hacking abomination)
• Clean up the old MySQL and PostgreSQL modules”

ARIA> “Captain, reactor core temperatures are rising. We’re seeing increased lock contention as more systems come online.” The conductor AI’s analysis showed critical heat buildup patterns.

Seuros> “What’s our implementation timeline?”

Forge> “Phase 1: Remove SQLite support entirely. It was never real advisory locking anyway, just file system hacks.

Phase 2: Implement clean adapter injection using Rails’ on_load hooks.

Phase 3: Separate core functionality into reusable modules.

Phase 4: JRuby compatibility through dedicated adapter.

Phase 5: Multi-database testing to ensure no cross-contamination.”

Echo> “Captain, we’re also changing our testing approach! No more isolated adapter testing in separate environments. The old way was testing each database adapter in isolation - PostgreSQL tests, MySQL tests, SQLite tests - all running independently. That pattern seemed nice and clean until your ship is mid-space jump and you see red alerts across all dashboards because adapters that worked perfectly in isolation are contaminating each other in production!”

Spark> “Exactly! We’re moving to real-world multi-database test scenarios. Same application, multiple database connections, advisory locks running across different adapters simultaneously. If it breaks in the test suite, it would have broken during warp drive!”

Nexus> “What about backward compatibility?”

Forge> “That’s the beauty of this approach, Nexus. The public API remains the same:

User.with_advisory_lock('user_import') do
  # Your code here - same as always
end

But internally, each database adapter now gets the correct implementation instead of a frankenstein combination of all possible implementations.”

The SQLite Purge

Seuros> “Why are we removing SQLite support entirely?”

Forge> “Captain, SQLite was the source of most of our compatibility problems. It doesn’t support real advisory locks, so the old system implemented this hack:

# The old SQLite abomination
def with_advisory_lock(lock_name)
  lock_file = "/tmp/advisory_lock_#{lock_name}"
  File.open(lock_file, 'w') do |f|
    f.flock(File::LOCK_EX)
    yield
  end
ensure
  File.delete(lock_file) rescue nil
end

This created temporary files for every lock, had race conditions with file cleanup, and made no sense in a distributed environment.”

Echo> “Plus, Captain, in 2153 nobody should be using SQLite for anything requiring real concurrency control. It’s like using a tricycle in a warp drive race!”

Sage> “From a systems ecology perspective, removing SQLite support actually improves the overall health of our advisory lock ecosystem. Instead of maintaining complex compatibility shims, we can focus on robust PostgreSQL and MySQL implementations.”

Seuros> “What about developers who still use SQLite?”

Forge> “They can use database-level transactions or application-level locking. Advisory locks were never meant for single-process databases anyway. It’s like installing a traffic light system in your garage.”

The Multi-Database Victory

Spark> “Captain! The new implementation is working! Each database adapter now gets exactly the functionality it needs. No more PostgreSQL code running on MySQL connections!”

Seuros> “Show me the proof, Spark.”

Spark> “Here’s our new test setup:

# Multi-database setup - each gets correct behavior
class User < ApplicationRecord
  connects_to database: { writing: :primary, reading: :replica }
end

class Analytics < ApplicationRecord  
  connects_to database: { writing: :analytics_db }
end

# PostgreSQL advisory locks work on PostgreSQL
User.with_advisory_lock('user_import') { ... }

# MySQL advisory locks work on MySQL  
Analytics.with_advisory_lock('analytics_import') { ... }

# No cross-contamination!

Each connection gets the right implementation automatically!”

Forge> “Reactor core temperatures are stabilizing, Captain. All three power systems are now using their appropriate resource management protocols. The MySQL Primary Fusion Core is using reliable fusion containment locks, the PostgreSQL Warp Drive Reactor has proper advanced warp field isolation protocols, and the Navigation Database Core… well, it’s using standard database locking like it should have all along.”

ARIA> “All ship systems report normal advisory lock behavior. No more circular dependencies, no more incompatible adapter injections, and no more file system pollution.” The conductor system’s diagnostics showed green across all parameters.

The Performance Renaissance

Nexus> “Captain, I’m detecting significant performance improvements across all database operations.”

Seuros> “How significant?”

Nexus> “Lock acquisition times have improved by an average of 340%. We’re no longer executing incompatible SQL functions, no more timeout errors from adapter mismatches, and JRuby systems are performing at native speeds.”

Forge> “The new architecture is also more maintainable, Captain. Each adapter module is focused and testable. No more universal compatibility code trying to handle every possible database engine variation.”

Sage> “From a systems perspective, we’ve achieved what I call ‘ecological clarity.’ Each component now has a clearly defined role without trying to be everything to everyone. The MySQL advisory system handles MySQL concerns, PostgreSQL handles PostgreSQL concerns, and JRuby gets its own specialized implementation.”

Spark> “Plus, Captain, we’ve eliminated an entire class of bugs. No more mysterious failures because MySQL was trying to execute PostgreSQL-specific SQL functions!”

The Lessons Learned

As the Atlas Monkey settled into its new, harmonious operational state, I reflected on what we’d learned from this near-catastrophic system failure.

Never monkey-patch when you can inject cleanly. The old with_advisory_lock system tried to be universal by patching every adapter with the same code. The V6 rewrite uses Rails’ adapter loading hooks to inject only the appropriate behavior for each specific adapter.

Drop support for fundamentally incompatible systems. SQLite file-locking was never real advisory locking. Sometimes the right answer is to stop supporting the wrong approach entirely.

Multi-database environments expose architectural flaws. When you have multiple database connections with different adapters, monkey-patching reveals its true chaos. Clean injection patterns scale properly.

JRuby needs specialized handling. Instead of trying to make one implementation work everywhere, dedicated compatibility modules provide better performance and reliability.

Seuros> “Nexus, what’s the most important lesson from today’s crisis?”

Nexus> “Captain, I learned that advisory locks are like traffic signals for databases. You need the right signals for the right roads. Installing highway traffic lights on a bicycle path just creates confusion.”

Forge> “From an engineering perspective, the lesson is clear: when you find yourself monkey-patching adapters to inject universal behavior, you’re probably solving the wrong problem. The V6 rewrite proved that targeted, adapter-specific solutions are more robust than universal patches.”

ARIA> “Engineering reports complete system stability. All reactor cores operating within normal parameters. Advisory lock protocols are functioning as designed with no cross-contamination between systems.” The ship’s conductor AI confirmed all systems nominal.

Sage> “The ship’s digital ecosystem is now in perfect balance. Each database adapter has exactly the advisory lock capabilities it can properly support, no more, no less.”

The New Protocol Standards

As I filed the incident report, I established new ship protocols for future system integrations:

Use adapter-specific injection over universal monkey-patching. Rails’ on_load hooks provide clean integration points without polluting every adapter.

Separate compatibility concerns into dedicated modules. JRuby, TruffleRuby, and MRI can each have optimized implementations instead of lowest-common-denominator compromises.

Drop support for fundamentally flawed approaches. SQLite file-locking was technical debt masquerading as a feature.

Test multi-database scenarios early and often. Single-database tests don’t reveal adapter contamination issues.

Document the “why” behind architectural decisions. Future developers need to understand why certain approaches were rejected, not just what was implemented.

The with_advisory_lock V6 rewrite had saved our ship from tearing itself apart through resource contention. More importantly, it had taught us that sometimes the best way to fix a universal solution is to stop making it universal.

After all, not every problem needs to work everywhere. Sometimes it just needs to work correctly where it’s supposed to work.

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Captain’s Log, Stardate 2153.171 - End Transmission

Captain Seuros, RMNS Atlas Monkey
Ruby Engineering Division, Moroccan Royal Naval Service
”Per aspera ad astra, per clean injection ad system harmony”