On Mon, 24 Jun 2019 at 22:16, Michael Paquier <michael@paquier.xyz> wrote:
>
> On Sat, Jun 15, 2019 at 12:25:12PM +1200, David Rowley wrote:
> > With the attached version I'm just calling table_finish_bulk_insert()
> > once per partition at the end of CopyFrom(). We've got an array with
> > all the ResultRelInfos we touched in the proute, so it's mostly a
> > matter of looping over that array and calling the function on each
> > ResultRelInfo's ri_RelationDesc. However, to make it more complex,
> > PartitionTupleRouting is private to execPartition.c so we can't do
> > this directly... After staring at my screen for a while, I decided to
> > write a function that calls a callback function on each ResultRelInfo
> > in the PartitionTupleRouting.
>
> Don't take me bad, but I find the solution of defining and using a new
> callback to call the table AM callback not really elegant, and keeping
> all table AM callbacks called at a higher level than the executor
> makes the code easier to follow. Shouldn't we try to keep any calls
> to table_finish_bulk_insert() within copy.c for each partition
> instead?
I'm not quite sure if I follow you since the call to
table_finish_bulk_insert() is within copy.c still.
The problem was that PartitionTupleRouting is private to
execPartition.c, and we need a way to determine which of the
partitions we routed tuples to. It seems inefficient to flush all of
them if only a small number had tuples inserted into them and to me,
it seems inefficient to add some additional tracking in CopyFrom(),
like a hash table to store partition Oids that we inserted into. Using
PartitionTupleRouting makes sense. It's just a question of how to
access it, which is not so easy due to it being private.
I did suggest a few other ways that we could solve this. I'm not so
clear on which one of those you're suggesting or if you're thinking of
something new.
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
