Topic
A technique that reuses a limited set of database or network connections across clients, cutting overhead but risking shared session state.
postgres-js leaves a connection's row cursor set after a query fails mid-stream, so one team's LIMIT 500 query came back with 813 entries. With the one-line fix an open pull request since October 2025, pooled users have to patch the driver themselves.
Reality
The five options that decide which private key opens a client certificate lived in a struct libcurl's connection-reuse check never reads, so two handles sharing a pool could share one authenticated connection. Commit 7541ae5 moves them.
Reality
The BootSaaS walkthrough puts each customer's business tables in their own PostgreSQL schema, after pricing database-per-tenant at 1,000 HikariCP pools for 1,000 tenants under Spring Boot's default data source setup.
Reality
A rolling deploy kept serving deleted JSON fields to a slice of traffic while stickiness was switched off in the balancer config, and the connection doing it was an idle socket held by a module-level requests.Session.
Reality
Neki puts a fleet of connection-owning routers in front of sharded Postgres, each emitting a topology plan you can read with EXPLAIN (NEKI_PLAN). Sessions live on the router holding them, so losing one is visible to the client.
Reality
Najeeb Ullah traces intermittent SocketExceptions in an ASP.NET Core payments service to connection lifecycle, where each per-request client gets its own pool and each close parks a local port in TIME_WAIT while CPU, memory and database graphs stay flat.
Reality
A cron built to defeat Render's 15-minute spin-down spent the workspace's shared machine-hour budget in about ten days, and the suspension that followed took production and staging down together.
Reality
A dev.to tutorial benchmarks naive multi-tenant Row-Level Security at roughly 575 times slower than no policy at all. The variable is function volatility, not schema or traffic.
Reality
Postgres refusing connections is a counting problem. Install a pooler before you find the multiplier and you buy the same outage next month, plus one more hop in the path.
Reality
A dev.to walkthrough flags two upgrade traps: migrate dev no longer runs your seed script, and seeding through the pooled endpoint breaks long transactions and prepared statements.
Reality