Re: SparkSQL - Limit pushdown on BroadcastHashJoin

Thanks Reynold. Not sure why doExecute is not invoked, since CollectLimit does not support wholeStage case class CollectLimit(limit: Int, child: SparkPlan) extends UnaryNode { I will dig further into this. Zhan Zhang On Apr 18, 2016, at 10:36 PM, Reynold Xin

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

Anyway we can verify this easily. I just added a println to each row and verified that only limit + 1 row was printed after the join and before the limit. It'd be great if you do some debugging yourself and see if it is going through some other code path. On Mon, Apr 18, 2016 at 10:35 PM,

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

But doExecute is not called? On Mon, Apr 18, 2016 at 10:32 PM, Zhan Zhang wrote: > Hi Reynold, > > I just check the code for CollectLimit, there is a shuffle happening to > collect them in one partition. > > protected override def doExecute(): RDD[InternalRow] = { >

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

Hi Reynold, I just check the code for CollectLimit, there is a shuffle happening to collect them in one partition. protected override def doExecute(): RDD[InternalRow] = { val shuffled = new ShuffledRowRDD( ShuffleExchange.prepareShuffleDependency( child.execute(), child.output,

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

Unless I'm really missing something I don't think so. As I said, it goes through an iterator and after processing each stream side we do a shouldStop check. The generated code looks like /* 094 */ protected void processNext() throws java.io.IOException { /* 095 */ /*** PRODUCE: Project

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

>From the physical plan, the limit is one level up than the WholeStageCodegen, >Thus, I don’t think shouldStop would work here. To move it work, the limit has >to be part of the wholeStageCodeGen. Correct me if I am wrong. Thanks. Zhan Zhang On Apr 18, 2016, at 11:09 AM, Reynold Xin

Re: SparkSQL - Limit pushdown on BroadcastHashJoin

While you can't automatically push the limit *through* the join, we could push it *into* the join (stop processing after generating 10 records). I believe that is what Rajesh is suggesting. On Tue, Apr 12, 2016 at 7:46 AM, Herman van Hövell tot Westerflier < hvanhov...@questtec.nl> wrote: > I am