lpsmith/postgresql-simple — pull request #62 by joeyadams (2013-05-20 08:47:25+00:00)
Title: Add support for savepoints

This adds `withSavepoint`, which acts sort of like `withTransaction` when you are already in a transaction. Savepoint names are generated automatically, and are represented by the abstract `Savepoint` type. More direct methods like `newSavepoint` are exported only from Database.PostgreSQL.Simple.Transaction.

Compatibility: This adds a field to the `Connection` type for generating savepoint names, so it will break any program that imports Database.PostgreSQL.Simple.Internal and creates its own `Connection` object.