By the way in the initial discussion on parallel infrastructure
https://www.postgresql.org/message-id/20150208002027.GH9201%40alap3.anarazel.de
I've seen a proposal to set the worker's PGXACT->xmin
to be the minimum of the top transaction id and the snapshots.
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Best regards,
Pavel Borisov
Postgres Professional: http://postgrespro.com <http://www.postgrespro.com>