On Mon, Nov 7, 2016 at 8:40 AM, Shay Rojansky <r...@roji.org> wrote: > > 1. Does everyone agrees that renaming the existing datatype without >> > changing the OID? >> > >> > >> > As I said before, Npgsql for one loads data types by name, not by OID. >> > So this would definitely cause breakage. >> >> Why would that cause breakage? > > > Well, the first thing Npgsql does when it connects to a new database, is > to query pg_type. The type names are used to associate entries with type > handlers, avoiding the hard-coding of OIDs in code. So if the type name > "macaddr" suddenly has a new meaning and its wire representation is > different breakage will occur. It is possible to release new versions of > Npgsql which will look at the PostgreSQL version and say "we know that in > PostgreSQL < 10 macaddr means this, but in >= 10 it means that". But that > doesn't seem like a good solution, plus old versions of Npgsql from before > this change won't work. >
The new datatype that is going to replace the existing one works with both 6 and 8 byte MAC address and stores it a variable length format. This doesn't change the wire format. I don't see any problem with the existing applications. The new datatype can recv and send 8 byte MAC address also. Regards, Hari Babu Fujitsu Australia
