Re: not(t_xmax = 0)

Alejandro Carrillo wrote:

> this function didn't work to know if a row can surely dead?
>
> http://doxygen.postgresql.org/tqual_8c_source.html#l01236

Sure, as long as you call it after HeapTupleSatisfiesMVCC(), as the
comment specifies. Also note that not all deleted or updated tuples
will be retained for very long; HOT pruning and autovacuum can
clean up dead tuples at unpredictable times.  But if you want to
know which among the old tuples that are still in the heap will go
away when the next vacuum against the table runs, that would be one
way to do it.

-Kevin