Andres Freund wrote:

> I think this patch is a seriously bad idea. For one, it's not actually
> doing anything about the problem - the tuple can be accessed without
> freezing getting involved.

Normal access other than freeze is not a problem, because other code
paths do check for HEAP_XMAX_INVALID and avoid access to Xmax if that's

> For another, it will increase wall traffic for freezing of short lived
> tuples considerably, without any benefit.

True.  I didn't actually try to run this; it was just for demonstration
purposes.  It'd need some cooperation from heap_tuple_needs_freeze in
order to work at all, for one thing.

Álvaro Herrera      
PostgreSQL Development, 24x7 Support, Training & Services

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