Zero-downtime migrations
Postgres FM
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The Complexity of PostgreSQL
Pre postgres 11, when we create a new table with default that caused full table rewrite. Post-casset needs to be fully scanned at creation during this time,. It holds this very expensive lock and can be done in two phases. So first you say not valid constraint, then you have second check type of our problem. You need a full scan before creating it, if you're going to do it properly. Before post- casset level is terrible absolutely terrible. Period. But now... Yeah I like the term 'online operation' A good friend of mine who gave me this term from SQL World as well: "I like it online"
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