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Improve PostgreSQL performance: Diagnose and mitigate lock manager contention
Originally from aws.amazon.com/blogs/database/category/database/amazon-aurora/feed/
July 30, 2025 Read Original Article

Ah, yes, the age-old mystery: "Are your database read operations unexpectedly slowing down as your workload scales?" Truly, a profound question for the ages. I mean, who could possibly expect that more people trying to access more data at the same time might lead to, you know, delays? It's not like databases have been doing this for decades, or that scaling issues are the very bedrock of half the industry's consultants. "Bottlenecks that aren’t immediately obvious," they say. Right, because the first place anyone looks when their system is sluggish is usually the coffee machine, not the database getting hammered into submission.

Then we get to the good stuff: "Many organizations running PostgreSQL-based systems." Shocking! Not MySQL, not Oracle, but PostgreSQL! The sheer audacity of these organizations to use a widely adopted, open-source database and then experience, gasp, scaling challenges. And what's the culprit? "Many concurrent read operations access tables with numerous partitions or indexes." So, in other words, they're using a database... like a database? With data structures designed for performance and partitioning for management? My word, it’s almost as if the system is being utilized!

But wait, there's a villain in this tale, a true architectural betrayal: these operations can "even exhaust PostgreSQL’s fast path locking mechanism." Oh, the horror! Exhaustion! It sounds less like a technical limitation and more like PostgreSQL has been up all night watching cat videos and just needs a good nap. And when this poor mechanism finally collapses into a heap, what happens? The system is "forcing the system to use shared memory locks." Forcing! As if PostgreSQL is being dragged kicking and screaming into a dark alley of less-optimal lock management. It’s almost as if it’s a designed fallback mechanism for when the fast path isn't feasible, rather than some catastrophic, unforeseen failure. I'm sure the next sentence, tragically cut short, was going to reveal that "The switch... will invariably lead to a 'revolutionary' new caching layer that just shoves more hardware at the problem, or a whitepaper recommending you buy more RAM. Because when in doubt, just add RAM. It's the silicon equivalent of a participation trophy for your database.