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How are you saving the data? There are two relevant 2GB limits: 1. Caching 2. Shuffle For caching, a partition is turned into a single block. For shuffle, each map partition is partitioned into R blocks, where R = number of reduce tasks. It is unlikely a shuffle block > 2G, although it can still happen. I think the 2nd problem is easier to fix than the 1st, because we can handle that in the network transport layer. It'd require us to divide the transfer of a very large block into multiple smaller blocks. On Tue, Feb 3, 2015 at 3:00 PM, Imran Rashid <iras...@cloudera.com> wrote: > Michael, > > you are right, there is definitely some limit at 2GB. Here is a trivial > example to demonstrate it: > > import org.apache.spark.storage.StorageLevel > val d = sc.parallelize(1 to 1e6.toInt, 1).map{i => new > Array[Byte](5e3.toInt)}.persist(StorageLevel.DISK_ONLY) > d.count() > > It gives the same error you are observing. I was under the same > impression as Sean about the limits only being on blocks, not partitions -- > but clearly that isn't the case here. > > I don't know the whole story yet, but I just wanted to at least let you > know you aren't crazy :) > At the very least this suggests that you might need to make smaller > partitions for now. > > Imran > > > On Tue, Feb 3, 2015 at 4:58 AM, Michael Albert < > m_albert...@yahoo.com.invalid> wrote: > >> Greetings! >> >> Thanks for the response. >> >> Below is an example of the exception I saw. >> I'd rather not post code at the moment, so I realize it is completely >> unreasonable to ask for a diagnosis. >> However, I will say that adding a "partitionBy()" was the last change >> before this error was created. >> >> >> Thanks for your time and any thoughts you might have. >> >> Sincerely, >> Mike >> >> >> >> Exception in thread "main" org.apache.spark.SparkException: Job aborted >> due to stage failure: Task 4 in stage 5.0 failed 4 times, most recent >> failure: Lost task 4.3 in stage 5.0 (TID 6012, >> ip-10-171-0-31.ec2.internal): java.lang.RuntimeException: >> java.lang.IllegalArgumentException: Size exceeds Integer.MAX_VALUE >> at sun.nio.ch.FileChannelImpl.map(FileChannelImpl.java:828) >> at org.apache.spark.storage.DiskStore.getBytes(DiskStore.scala:123) >> at org.apache.spark.storage.DiskStore.getBytes(DiskStore.scala:132) >> at >> org.apache.spark.storage.BlockManager.doGetLocal(BlockManager.scala:517) >> at >> org.apache.spark.storage.BlockManager.getBlockData(BlockManager.scala:307) >> at >> org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) >> at >> org.apache.spark.network.netty.NettyBlockRpcServer$$anonfun$2.apply(NettyBlockRpcServer.scala:57) >> at >> scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) >> at >> scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) >> at >> scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) >> at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:108) >> at >> scala.collection.TraversableLike$class.map(TraversableLike.scala:244) >> at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:108) >> at >> org.apache.spark.network.netty.NettyBlockRpcServer.receive(NettyBlockRpcServer.scala:57) >> >> >> ------------------------------ >> *From:* Sean Owen <so...@cloudera.com> >> *To:* Michael Albert <m_albert...@yahoo.com> >> *Cc:* "u...@spark.apache.org" <u...@spark.apache.org> >> *Sent:* Monday, February 2, 2015 10:13 PM >> *Subject:* Re: 2GB limit for partitions? >> >> The limit is on blocks, not partitions. Partitions have many blocks. >> >> It sounds like you are creating very large values in memory, but I'm >> not sure given your description. You will run into problems if a >> single object is more than 2GB, of course. More of the stack trace >> might show what is mapping that much memory. >> >> If you simply want data into 1000 files it's a lot simpler. Just >> repartition into 1000 partitions and save the data. If you need more >> control over what goes into which partition, use a Partitioner, yes. >> >> >> >> On Mon, Feb 2, 2015 at 8:40 PM, Michael Albert >> <m_albert...@yahoo.com.invalid> wrote: >> > Greetings! >> > >> > SPARK-1476 says that there is a 2G limit for "blocks". >> > Is this the same as a 2G limit for partitions (or approximately so?)? >> > >> > >> > What I had been attempting to do is the following. >> > 1) Start with a moderately large data set (currently about 100GB, but >> > growing). >> > 2) Create about 1,000 files (yes, files) each representing a subset of >> the >> > data. >> > >> > The current attempt I am working on is something like this. >> > 1) Do a "map" whose output key indicates which of the 1,000 files it >> will go >> > into and whose value is what I will want to stick into the file. >> > 2) Partition the data and use the body of mapPartition to open a file >> and >> > save the data. >> > >> > My apologies, this is actually embedded in a bigger mess, so I won't >> post >> > it. >> > >> > However, I get errors telling me that there is an >> "IllegalArgumentException: >> > Size exceeds Inter.MAX_VALUE", with sun.nio.ch.FileChannelImpl.map at >> the >> > top of the stack. This leads me to think that I have hit the limit or >> > partition and/or block size. >> > >> > Perhaps this is not a good way to do it? >> > >> > I suppose I could run 1,000 passes over the data, each time collecting >> the >> > output for one of my 1,000 final files, but that seems likely to be >> > painfully slow to run. >> > >> > Am I missing something? >> > >> > Admittedly, this is an odd use case.... >> > >> > Thanks! >> > >> > Sincerely, >> > Mike Albert >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: user-unsubscr...@spark.apache.org >> For additional commands, e-mail: user-h...@spark.apache.org >> >> >> >> >> >