Hello Devs,
I am investigating how matrix vector multiplication can scale for an
IndexedRowMatrix in mllib.linalg.distributed.
Currently, I am broadcasting the vector to be multiplied on the right.
The IndexedRowMatrix is stored across a cluster with up to 16 nodes,
each with >200 GB of memory. The spark driver is on an identical node,
having more than 200 Gb of memory.
In scaling n, the size of the vector to be broadcast, I find that the
maximum size of n that I can use is 2^26. For 2^27, the broadcast will
fail. The array being broadcast is of type Array[Double], so the
contents have size 2^30 bytes, which is approximately 1 (metric) GB.
I have read in PR [SPARK-3721] [PySpark] "broadcast objects larger
than 2G" that this should be supported (I assume this works for scala,
as well?). However, when I increase n to 2^27 or above, the program
invariably crashes at the broadcast.
The problem stems from the size of the result block to be sent in
BlockInfo.scala; the size is reportedly negative. An example error log
is shown below.
If anyone has more experience or knowledge of why this broadcast is
failing, I'd appreciate the input.
--
Thanks,
Mike
55584:INFO:MemoryStore:ensureFreeSpace(-2147480008) called with
curMem=0, maxMem=92610625536:
55584:INFO:MemoryStore:Block broadcast-2 stored as values in memory
(estimated size -2147480008.0 B, free 88.3 GB):
Exception in thread "main" java.lang.IllegalArgumentException:
requirement failed: sizeInBytes was negative: -2147480008
at scala.Predef$.require(Predef.scala:233)
at org.apache.spark.storage.BlockInfo.markReady(BlockInfo.scala:55)
at org.apache.spark.storage.BlockManager.doPut(BlockManager.scala:815)
at
org.apache.spark.storage.BlockManager.putIterator(BlockManager.scala:638)
at
org.apache.spark.storage.BlockManager.putSingle(BlockManager.scala:996)
at
org.apache.spark.broadcast.TorrentBroadcast.writeBlocks(TorrentBroadcast.scala:99)
at
org.apache.spark.broadcast.TorrentBroadcast.<init>(TorrentBroadcast.scala:85)
at
org.apache.spark.broadcast.TorrentBroadcastFactory.newBroadcast(TorrentBroadcastFactory.scala:34)
at
org.apache.spark.broadcast.BroadcastManager.newBroadcast(BroadcastManager.scala:63)
at org.apache.spark.SparkContext.broadcast(SparkContext.scala:1297)
at
org.apache.spark.mllib.linalg.distributed.IndexedRowMatrix.multiply(IndexedRowMatrix.scala:184)
at himrod.linalg.KrylovTests$.main(KrylovTests.scala:172)
at himrod.linalg.KrylovTests.main(KrylovTests.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at
org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:666)
at
org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:178)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:203)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:118)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
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