On Thu, Sep 18, 2014 at 9:17 PM, cowwoc <cowwoc@xxxxxxxxxxxxxxxx> wrote: > I did a quick search and noticed that 8 years ago, a Skype employee provided > a patch for migrating to a 64-bit TXID: > http://postgresql.1045698.n5.nabble.com/RFC-txid-module-for-64-bit-external-transaction-IDs-tt1947503.html Actually, this patch was supposed to: """ The goal is to make PostgreSQL internal transaction ID and snapshot data usable externally. They cannot be used directly as the internal 4-byte value wraps around and thus breaks indexing. """ This stuff was committed to PostgreSQL in essentially the same form years ago: http://www.postgresql.org/docs/devel/static/functions-info.html#FUNCTIONS-TXID-SNAPSHOT It's just a way of getting a stable 64-bit xid value for external use, by adding an epoch count to the representation. Nothing more. The most obvious reason for not using 64-bit xid values is that they require more storage than 32-bit values. There is a patch floating around that makes it safe to not forcibly safety shutdown the server where currently it is necessary, but it doesn't work by making xids 64-bit. -- Regards, Peter Geoghegan -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
