"Tom Lane" <[EMAIL PROTECTED]> writes: > "Ana Carolina Brito de Almeida" <[EMAIL PROTECTED]> writes: >> So, I would like to know the differences between bucket and batch. > > A bucket is, well, one bucket of a hash table --- it holds all the > tuples that have the same hash code (for as many bits of the hash > code as we are choosing to use). We try to size the hash table with > enough buckets so there's not more than 10 tuples per bucket on > average. > > A batch is a range of buckets that we process at the same time.
Note that we don't currently do batches for hash aggregates, only joins currently. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production Tuning -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
