execGrouping.c limit on work_mem
In BuildTupleHashTable
/* Limit initial table size request to not more than work_mem */
nbuckets = Min(nbuckets, (long) ((work_mem * 1024L) / entrysize));
Is this a good idea? If the caller of this code has no respect for
work_mem, they are still going to blow it out of the water. Now we will
just do a bunch of hash-table splitting in the process. That is only going
to add to the pain.
Also:
* false if it existed already. ->additional_data in the new entry has
The field is just ->additional, not ->additional_data
Cheers,
Jeff
Jeff Janes <jeff.janes@gmail.com> writes:
In BuildTupleHashTable
/* Limit initial table size request to not more than work_mem */
nbuckets = Min(nbuckets, (long) ((work_mem * 1024L) / entrysize));
Is this a good idea? If the caller of this code has no respect for
work_mem, they are still going to blow it out of the water. Now we will
just do a bunch of hash-table splitting in the process. That is only going
to add to the pain.
It looks perfectly reasonable to me. The point I think is that the caller
doesn't have to be very careful about calculating its initial request
size.
regards, tom lane
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers