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Postgres Internals
Real Postgres incidents, explained from the inside. The long version of each Instagram reel.
- The counter that ran out Postgres transaction IDs are 32-bit. At Mailchimp's Mandrill, one shard hit the limit and the database stopped accepting writes. Email sending resumed about 40 hours later.
- UPDATE doesn't update In Postgres, an UPDATE writes a whole new copy of the row. In 2016 Uber put the cost of that, write amplification, first on its list of reasons for moving from Postgres to MySQL.