Hi, What do you think about adding hooks for transaction ID and snapshot acquisition? Those hooks could be located in AssignTransactionId:xact.c for transaction ID and GetTransactionSnapshot:snapmgr.c for snapshots. This is useful for multi-master applications that use external tools to feed with unique transaction IDs and global snapshots all the nodes of a cluster in order to maintain global data consistency and visibility, one of the examples being cluster applications like Postgres-XC.
Opinions? -- Michael
