The Curious Case of the Table-Locking UPDATE Query | Heroku
I maintain an internal-facing service at Heroku that does metadata processing. It's not real-time, so there's plenty of slack for when things go wrong. Recently I discovered that the system was getting bogged down to the point where no jobs were being executed at all. After hours of debugging, I found the problem was an UPDATE on a single row on a single table was causing the entire table to lock, which caused a lock queue and ground the whole process to a halt. This post is a story about how the problem was debugged and fixed and why such a seemingly simple query caused so much harm.
The Curious Case of the Table-Locking UPDATE Query | Heroku #ruby #rubydeveloper #rubyonrails #heroku https://www.rubyonrails.ba/single/the-curious-case-of-the-table-locking-update-query-heroku
Nezir Zahirovic
Contractor Ruby On Rails (8+ years) / MCPD .Net / C# / Asp.Net / CSS / SQL / (11 years)
