Thorny question about TRANSACTION_TIMESTAMP()

[leiffoged]

If I write data that involves nodes A, B, and C, and then run TRANSACTION_TIMESTAMP() on node D immediately after A, B, and C acknowledge my write, can I then take the TRANSACTION_TIMESTAMP() value (from node D) and make an AS OF SYSTEM TIME query using that timestamp back to nodes A, B, or C and be guaranteed to see the data I wrote?

Wondering if this works or clock differences might make this sometimes fail. And, if this doesn't work, is there a good way (when committing a transaction) where I can get a timestamp that can be guaranteed to be after the transaction?

[ajwerner]

This is a timely question. There's been some demand for this in the past. See #79591. I have a partial implementation in #80848 which has come again just this week. I intend to do something about it in the coming weeks. I hope to take the outcome of that and try to backport it into a 22.2 patch release later this winter.