[wbl]

Read committed is explicitly asking for hard mode. If you want a simple life stick with Serializable as always. It took years before people found anomalies in Repeatable Read in Postgres. This stuff is hard even for world class researchers.

[paulryanrogers]

How does one get serializable in a multi-writer system without a lot more locking and having to retry at app layer?

[Diggsey]

You always need app-level retries for SERIALIZABLE isolation level. You don't need any explicit locking - the database should handle that for you (and in the case of PostgreSQL, locking is not the only tool it uses for avoiding serialization anomalies).

The strategy I use is to keep transactions as small as possible, and have retry functionality built into the transaction abstraction, so the buesiness logic doesn't really need to worry about it. I also explicitly use read-only transactions where possible.