Re: Why does execReplication.c lock tuples?

Hi,

On 20/01/2019 21:03, Andres Freund wrote:
> Hi,
> 
> Currently RelationFindReplTupleByIndex(), RelationFindReplTupleSeq()
> lock the found tuple. I don't quite get what that achieves - why isn't
> dealing with concurrency in the table_update/delete calls at the
> callsites sufficient? As far as I can tell there's no meaningful
> concurrency handling in the heap_lock_tuple() paths, so it's not like we
> follow update chains or anything. 
> 

Yeah that's leftover from the conflict detection/handling code that I
stripped away to keep the patched manageable size-wise. As things stand
now we could remove that and use normal heap_update instead of simple
variant. It'll be likely be needed again if we add conflict handling in
the future, but perhaps we could be smarter about it then (i.e. I can
imagine that it will be per table anyway, not necessarily default behavior).

-- 
  Petr Jelinek                  http://www.2ndQuadrant.com/
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