By creating a separate function for the locking and updating of rows, we ensure that the `BEGIN/END` transaction is handled per iteration rather than at the very end, so we only lock rows while they are being processed. Since Postgres does not support nested transaction blocks, calling a defined function from within an anonymous function block seemed to be the easiest and clearest path to achieve this.
https://gist.github.com/aanari/349c7d97ed50c6f69930#file-bat...
By creating a separate function for the locking and updating of rows, we ensure that the `BEGIN/END` transaction is handled per iteration rather than at the very end, so we only lock rows while they are being processed. Since Postgres does not support nested transaction blocks, calling a defined function from within an anonymous function block seemed to be the easiest and clearest path to achieve this.