Ok, so it's something in the rest of the script that's causing this to happen. Ruslan, if you send your script, I can probably figure out why (usually, it's using another, non-agebraic udf in your foreach, or for pig 0.8, generating a constant in the foreach).
D On Thu, Nov 17, 2011 at 9:59 AM, pablomar <[email protected]> wrote: > according to the stack trace, the algebraic is not being used > it says > updateTop(Top.java:139) > exec(Top.java:116) > > On 11/17/11, Dmitriy Ryaboy <[email protected]> wrote: >> The top udf does not try to process all data in memory if the algebraic >> optimization can be applied. It does need to keep the topn numbers in memory >> of course. Can you confirm algebraic mode is used? >> >> On Nov 17, 2011, at 6:13 AM, "Ruslan Al-fakikh" <[email protected]> >> wrote: >> >>> Hey guys, >>> >>> >>> >>> I encounter java.lang.OutOfMemoryError when using TOP udf. It seems that >>> the >>> udf tries to process all data in memory. >>> >>> Is there a workaround for TOP? Or maybe there is some other way of getting >>> top results? I cannot use LIMIT since I need to 5% of data, not a constant >>> number of rows. >>> >>> >>> >>> I am using: >>> >>> Apache Pig version 0.8.1-cdh3u2 (rexported) >>> >>> >>> >>> The stack trace is: >>> >>> [2011-11-16 12:34:55] INFO (CodecPool.java:128) - Got brand-new >>> decompressor >>> >>> [2011-11-16 12:34:55] INFO (Merger.java:473) - Down to the last >>> merge-pass, >>> with 21 segments left of total size: 2057257173 bytes >>> >>> [2011-11-16 12:34:55] INFO (SpillableMemoryManager.java:154) - first >>> memory >>> handler call- Usage threshold init = 175308800(171200K) used = >>> 373454552(364701K) committed = 524288000(512000K) max = 524288000(512000K) >>> >>> [2011-11-16 12:36:22] INFO (SpillableMemoryManager.java:167) - first >>> memory >>> handler call - Collection threshold init = 175308800(171200K) used = >>> 496500704(484863K) committed = 524288000(512000K) max = 524288000(512000K) >>> >>> [2011-11-16 12:37:28] INFO (TaskLogsTruncater.java:69) - Initializing >>> logs' >>> truncater with mapRetainSize=-1 and reduceRetainSize=-1 >>> >>> [2011-11-16 12:37:28] FATAL (Child.java:318) - Error running child : >>> java.lang.OutOfMemoryError: Java heap space >>> >>> at java.util.Arrays.copyOfRange(Arrays.java:3209) >>> >>> at java.lang.String.<init>(String.java:215) >>> >>> at >>> java.io.DataInputStream.readUTF(DataInputStream.java:644) >>> >>> at >>> java.io.DataInputStream.readUTF(DataInputStream.java:547) >>> >>> at >>> org.apache.pig.data.BinInterSedes.readCharArray(BinInterSedes.java:210) >>> >>> at >>> org.apache.pig.data.BinInterSedes.readDatum(BinInterSedes.java:333) >>> >>> at >>> org.apache.pig.data.BinInterSedes.readDatum(BinInterSedes.java:251) >>> >>> at >>> org.apache.pig.data.BinInterSedes.addColsToTuple(BinInterSedes.java:555) >>> >>> at >>> org.apache.pig.data.BinSedesTuple.readFields(BinSedesTuple.java:64) >>> >>> at >>> org.apache.pig.data.InternalCachedBag$CachedBagIterator.hasNext(InternalCach >>> edBag.java:237) >>> >>> at org.apache.pig.builtin.TOP.updateTop(TOP.java:139) >>> >>> at org.apache.pig.builtin.TOP.exec(TOP.java:116) >>> >>> at org.apache.pig.builtin.TOP.exec(TOP.java:65) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperat >>> ors.POUserFunc.getNext(POUserFunc.java:245) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperat >>> ors.POUserFunc.getNext(POUserFunc.java:287) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperat >>> ors.POForEach.processPlan(POForEach.java:338) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperat >>> ors.POForEach.getNext(POForEach.java:290) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator >>> .processInput(PhysicalOperator.java:276) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperat >>> ors.POForEach.getNext(POForEach.java:240) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Re >>> duce.runPipeline(PigMapReduce.java:434) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Re >>> duce.processOnePackageOutput(PigMapReduce.java:402) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Re >>> duce.reduce(PigMapReduce.java:382) >>> >>> at >>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Re >>> duce.reduce(PigMapReduce.java:251) >>> >>> at >>> org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176) >>> >>> at >>> org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:572) >>> >>> at >>> org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:414) >>> >>> at org.apache.hadoop.mapred.Child$4.run(Child.java:270) >>> >>> at java.security.AccessController.doPrivileged(Native >>> Method) >>> >>> at javax.security.auth.Subject.doAs(Subject.java:396) >>> >>> at >>> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.ja >>> va:1127) >>> >>> at org.apache.hadoop.mapred.Child.main(Child.java:264) >>> >>> >>> >>> >>> >>> >>> >>> stderr logs >>> >>> Exception in thread "Low Memory Detector" java.lang.OutOfMemoryError: Java >>> heap space >>> >>> at >>> sun.management.MemoryNotifInfoCompositeData.getCompositeData(MemoryNotifInfo >>> CompositeData.java:42) >>> >>> at >>> sun.management.MemoryNotifInfoCompositeData.toCompositeData(MemoryNotifInfoC >>> ompositeData.java:36) >>> >>> at >>> sun.management.MemoryImpl.createNotification(MemoryImpl.java:168) >>> >>> at >>> sun.management.MemoryPoolImpl$CollectionSensor.triggerAction(MemoryPoolImpl. >>> java:300) >>> >>> at sun.management.Sensor.trigger(Sensor.java:120) >>> >>> >>> >>> >>> >>> Thanks in advance! >>> >> >
