Postgres 'Too Many Connections': Debugging Pgpool-II Limits
Debugging a Postgres 'too many connections' error through Pgpool-II's num_init_children and max_pool settings, and the fix that stopped clients queueing.
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Redis in Ruby on Rails: Cache Server and Job Queue
Redis serves two very different roles in a Rails app, a disposable read cache and a durable job queue, and conflating the two causes real outages.
GCP 502 Errors from GKE Readiness Probe Failures
A GKE 502 with 'failed_to_pick_backend' traced back to readiness probes failing on every pod at once, and the liveness probe and anti-affinity fixes that resolved it.
Pgpool-II: Middleware for PostgreSQL
Pgpool-II sits between PostgreSQL and its clients as a connection pooler and load balancer, and this covers the Kubernetes setup that keeps writes consistent.
When the OOM Killer Silently Kills a Background Job
A missed notification email traced back to the Linux OOM killer terminating a Sidekiq job mid-run, leaving a stuck Redis lock and no error logged anywhere.
Shared Databases Between Microservices Are a Code Smell
When two services share one database, a schema change in either one can silently break the other, and here is how to split ownership with APIs or events.
Soft Delete in Rails: Discard vs ActsAsParanoid
A comparison of Discard and ActsAsParanoid, the two common Rails soft-delete gems, and the query and unscope pitfalls each one introduces.
How Rails Loads Your App: Rake, Console, Server, and Tests
What Rails actually loads when you run a rake task, the console, the server, or tests, and how to load rake tasks in each environment when you need them.
Rails unscope: removing default scope conditions
How ActiveRecord's unscope method selectively removes where and order conditions from default scopes, with examples and alternatives like merge and unscoped.
Database Auditing: pg_audit vs audited vs paper_trail
A comparison of database auditing options, pg_audit, audited, paper_trail, Hibernate Envers, and SQL Server temporal tables, and when each one fits.