I haven't followed this at all, but I just skimmed over it and noticed
the CustomPlanMarkPos thingy; apologies if this has been discussed
before. It seems a bit odd to me; why isn't it sufficient to have a
boolean flag in regular CustomPlan to indicate that it supports
mark/restore?
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Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services