Ardent Performance Computing
performance
Why Postgres Breaks Kubernetes container_memory_working_set_bytes Metric
Kubernetes metric container_memory_working_set_bytes is used for evicting/killing pods with too much memory use, especially if memory request < limit (don’t do this with Postgres). The metric is calculated from cgroups v2 memory.stat as current-inactive_file [source]. You’d assume it’s a good metric for memory usage in kubernetes. But with Postgres, this metric is very inaccurate for … Continue reading
Happiness Hint: Alarm on Checkpoint Time
Before starting, I want to put a few things at the top: You probably should not change the checkpoint_timeout setting from its default of 5 minutes. Users who read tuning advice on the internet (or get bad AI advice) about increasing this setting usually don’t understand the risk and significance of trading for RTO/availability. Let’s … Continue reading
PGConf.dev 2026 Trip Summary
I’m back home from Vancouver. What a great week – in every way. I’ll try to share a few highlights here. Updated Happiness Hints First and foremost: after many years, the Happiness Hints have received a major update! Before the conference, I updated the hints based on all the feedback I’ve collected over the past … Continue reading
Zero autovacuum_vacuum_cost_delay, Write Storms, and You
A few days ago, Shaun Thomas published an article over on the pgEdge blog called [Checkpoints, Write Storms, and You]. I left a few comments [on LinkedIn]. This article is a great technical read about an important and overlooked topic – and I always love seeing real test results to illustrate the details. I don’t … Continue reading
Postgres client_connection_check_interval
Saw this post on LinkedIn yesterday: I also somehow missed this setting for years. And it’s crazy timing, because it’s right after I published a blog about seeing the exact problem this solves. In my blog post I mentioned “unexpected behaviors (bugs?) in… Postgres itself.” Turns out Postgres already has the fix; it’s just disabled … Continue reading
How Blocking-Lock Brownouts Can Escalate from Row-Level to Complete System Outages
This article is a shortened version. For the full writeup, go to https://github.com/ardentperf/pg-idle-test/tree/main/conn_exhaustion This test suite demonstrates a failure mode when application bugs which poison connection pools collide with PgBouncers that are missing peer config and positioned behind a load balancer. PgBouncer’s peering feature (added with v1.19 in 2023) should be configured if multiple PgBouncers are being used … Continue reading
Explaining IPC:SyncRep – Postgres Sync Replication is Not Actually Sync Replication
Postgres database-level “synchronous replication” does not actually mean the replication is synchronous. It’s a bit of a lie really. The replication is actually – always – asynchronous. What it actually means is “when the client issues a COMMIT then pause until we know the transaction is replicated.” In fact the primary writer database doesn’t need … Continue reading
Graviton2 versus Graviton4
Just a short post, because I thought this was pretty remarkable. Below, I have screenshots showing the CPU utilization of two AWS instances in us-west-2 which are running an identical workload. They are running the CloudNativePG playground, which is a production-like learning and testing environment (all running virtually inside the single ec2 instance, which can … Continue reading
Postgres Per-Connection Statistics
I’ve had a wish list for a few years now of observability-related things I’d love to see someday in community/open-source Postgres. A few items from my wish list: Wait event counters and cumulative time Wait event arguments (like object, block, etc – specific argument depends on the wait event) Comprehensive tracking of CPU time (ie. … Continue reading
Kubernetes Requests and Limits for Postgres
As Joe Drumgoole said a few days ago: so many Postgres providers. Aiven, AWS, Azure, Crunchy, DigitalOcean, EDB, GCP, Heroku, Neon, Nile, Oracle, Supabase, Tembo, Timescale, Xata, Yugabyte… 🤯 I’m sure there’s more I missed. And that’s not even the providers using Postgres underneath services they offer with a different focus than Postgres compatibility. (I … Continue reading
Disclaimer
This is my personal website. The views expressed here are mine alone and may not reflect the views of my employer.
contact: schneider @ ardentperf.com
Recent Comments