-Re: Hive QL - NOT IN, NOT EXIST
Stephen Boesch 2013-05-06, 04:44
@Peter Does the query plan demonstrate that the 3Meg row table is being
map-joined and the 400M table streamed through? That is what you want: but
you might either need to fiddle with hints to get it to happen
Read uuids s of feed into in-memory map on all nodes (mapjoin)
Stream the 400M message records through the in-memory maps, copying
id's from the "all feed uuids" map to a "matched feed uuid's map for
entries that have matches in the messages
Note: this way the 400M rows are only read once on the cluster.
You can see whether hive can manage this or if you write a custom m/r job
to do it.
2013/5/5 Peter Chu <[EMAIL PROTECTED]>
> It works but it takes a very long time because the subqueries in NOT IN
> contains 400 million rows (the message table in the example) and the feed
> table contains 3 million rows.
> SELECT uuid from feed f WHERE f.uuid NOT IN (SELECT uuid FROM message);
> > Date: Sun, 5 May 2013 20:25:15 -0700
> > From: [EMAIL PROTECTED]
> > Subject: Re: Hive QL - NOT IN, NOT EXIST
> > To: [EMAIL PROTECTED]
> > --- On Sun, 5/5/13, Peter Chu <[EMAIL PROTECTED]> wrote:
> > > I am wondering if there is any way to do this without resorting to
> > > using left outer join and finding nulls.
> > I have found this to be an acceptable substitute. Is it not working for