On Thu, 30 Jul 2026 at 08:51, Tristan Partin <[email protected]> wrote: > > In bug #19587[0], the user reported that hashchar() and > hashcharextended() were not producing the same results for the same > input because of sign extension depending on the platform.
This reminds me of [0], which saw the same difference in behaviour cause discrepancies in indexing behaviour when replicating across different architectures. That eventually led to a set of commits [1] that landed with PG18 that includes tracking the signedness of char in the control file, which turned this char-signedness incompatibility explicit. So, I don't think we guarantee the output of all 'immutable' functions to have no changes in output when the system is compiled on different platforms or with different settings. Collations are one example where the platform may change their output, char-signedness during compilation is another. Kind regards, Matthias van de Meent Databricks (https://www.databricks.com) [0] https://www.postgresql.org/message-id/[email protected] [1] 30666d1857, a8238f87f9, 1aab680591, and dfd8e6c73e
