Re: Transaction Snapshots and Hot Standby

On Sat, 2008-09-13 at 10:48 +0100, Florian G. Pflug wrote:

> The main idea was to invert the meaning of the xid array in the snapshot
> struct - instead of storing all the xid's between xmin and xmax that are
> to be considering "in-progress", the array contained all the xid's >
> xmin that are to be considered "completed".

> The downside is that the size of the read-only snapshot is theoretically
> unbounded, which poses a bit of a problem if it's supposed to live
> inside shared memory...

Why do it inverted? That clearly has problems.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support