Not a problem man-- can't wait to play with it this weekend!
On Fri, Jul 6, 2012 at 9:50 AM, Gabriel Reid <[email protected]> wrote: > Hi Josh, > > I've just committed the map side joins, after doing some more > extensive testing on it today. Unfortunately, I forgot to squash the > multiple commits into a single one (as I was planning on doing), but > it's all in there and working. > > - Gabriel > > On Fri, Jul 6, 2012 at 7:28 AM, Gabriel Reid <[email protected]> wrote: >> Thanks for making the JIRA issue. >> >> I was going to do some more testing an a "real" cluster later on today, and >> as long as that all checks out then this will be ready to go in as far as >> I'm concerned. >> >> I don't see any reason to hold back on the big renaming for this patch -- if >> you're ready to do the package renaming, please go ahead. >> >> As long as my testing later today checks out and there aren't any glaring >> issues from anyone who has tried the patch out, I'll probably be checking >> the patch in later today (so it'll probably be in before you do the renaming >> anyhow). >> >> - Gabriel >> >> >> On Friday 6 July 2012 at 00:11, Josh Wills wrote: >> >>> FYI: https://issues.apache.org/jira/browse/CRUNCH-3 to track this. >>> >>> Gabriel, is your feeling that this is ready to go in? I'm debating whether >>> or not to check this in before/after I do the massive com.cloudera -> >>> org.apache renaming. What do you think? >>> >>> On Tue, Jul 3, 2012 at 1:25 PM, Gabriel Reid <[email protected] >>> (mailto:[email protected])> wrote: >>> >>> > Hi Joe, >>> > >>> > Looking forward to hearing your feedback! This is still just a patch and >>> > not committed yet, and there's still definitely room for help (i.e. ideas >>> > on how to improve it, or do it totally differently), so certainly let me >>> > know if you've got some ideas. >>> > >>> > - Gabriel >>> > >>> > >>> > On Tuesday 3 July 2012 at 18:01, Joseph Adler wrote: >>> > >>> > > Awesome! Will give this a try soon... wish I could have helped with this >>> > one... >>> > > >>> > > On Tue, Jul 3, 2012 at 1:53 AM, Gabriel Reid <[email protected] >>> > > (mailto:[email protected])(mailto: >>> > [email protected] (mailto:[email protected]))> wrote: >>> > > > Thanks for pointing that out Chris. I'm guessing the mailing list is >>> > > > stripping out attachments(?). Once the JIRA is up and running then >>> > > > that will be taken care of I guess. >>> > > > >>> > > > The mime type on the last attempt was application/octet-stream, so >>> > > > I've renamed this to a .txt file to try to ensure that it'll get a >>> > > > text/plain mime type (although I don't know if that'll make a >>> > > > difference). I've also pasted it inline below, hopefully one of those >>> > > > solutions works. >>> > > > >>> > > > - Gabriel >>> > > > >>> > > > >>> > > > diff --git src/main/java/com/cloudera/crunch/impl/mr/MRPipeline.java >>> > > > src/main/java/com/cloudera/crunch/impl/mr/MRPipeline.java >>> > > > index 420e8dc..c8ba596 100644 >>> > > > --- src/main/java/com/cloudera/crunch/impl/mr/MRPipeline.java >>> > > > +++ src/main/java/com/cloudera/crunch/impl/mr/MRPipeline.java >>> > > > @@ -59,9 +59,9 @@ import com.google.common.collect.Sets; >>> > > > public class MRPipeline implements Pipeline { >>> > > > >>> > > > private static final Log LOG = LogFactory.getLog(MRPipeline.class); >>> > > > - >>> > > > + >>> > > > private static final Random RANDOM = new Random(); >>> > > > - >>> > > > + >>> > > > private final Class<?> jarClass; >>> > > > private final String name; >>> > > > private final Map<PCollectionImpl<?>, Set<Target>> outputTargets; >>> > > > @@ -75,15 +75,15 @@ public class MRPipeline implements Pipeline { >>> > > > public MRPipeline(Class<?> jarClass) throws IOException { >>> > > > this(jarClass, new Configuration()); >>> > > > } >>> > > > - >>> > > > - public MRPipeline(Class<?> jarClass, String name){ >>> > > > + >>> > > > + public MRPipeline(Class<?> jarClass, String name) { >>> > > > this(jarClass, name, new Configuration()); >>> > > > } >>> > > > - >>> > > > + >>> > > > public MRPipeline(Class<?> jarClass, Configuration conf) { >>> > > > - this(jarClass, jarClass.getName(), conf); >>> > > > + this(jarClass, jarClass.getName(), conf); >>> > > > } >>> > > > - >>> > > > + >>> > > > public MRPipeline(Class<?> jarClass, String name, Configuration conf) >>> > > > { >>> > > > this.jarClass = jarClass; >>> > > > this.name (http://this.name) = name; >>> > > > @@ -102,9 +102,9 @@ public class MRPipeline implements Pipeline { >>> > > > >>> > > > @Override >>> > > > public void setConfiguration(Configuration conf) { >>> > > > - this.conf = conf; >>> > > > + this.conf = conf; >>> > > > } >>> > > > - >>> > > > + >>> > > > @Override >>> > > > public PipelineResult run() { >>> > > > MSCRPlanner planner = new MSCRPlanner(this, outputTargets); >>> > > > @@ -125,8 +125,8 @@ public class MRPipeline implements Pipeline { >>> > > > boolean materialized = false; >>> > > > for (Target t : outputTargets.get(c)) { >>> > > > if (!materialized && t instanceof Source) { >>> > > > - c.materializeAt((SourceTarget) t); >>> > > > - materialized = true; >>> > > > + c.materializeAt((SourceTarget) t); >>> > > > + materialized = true; >>> > > > } >>> > > > } >>> > > > } >>> > > > @@ -144,7 +144,7 @@ public class MRPipeline implements Pipeline { >>> > > > cleanup(); >>> > > > return res; >>> > > > } >>> > > > - >>> > > > + >>> > > > public <S> PCollection<S> read(Source<S> source) { >>> > > > return new InputCollection<S>(source, this); >>> > > > } >>> > > > @@ -160,85 +160,120 @@ public class MRPipeline implements Pipeline { >>> > > > @SuppressWarnings("unchecked") >>> > > > public void write(PCollection<?> pcollection, Target target) { >>> > > > if (pcollection instanceof PGroupedTableImpl) { >>> > > > - pcollection = ((PGroupedTableImpl<?,?>) pcollection).ungroup(); >>> > > > + pcollection = ((PGroupedTableImpl<?, ?>) pcollection).ungroup(); >>> > > > } else if (pcollection instanceof UnionCollection || pcollection >>> > > > instanceof UnionTable) { >>> > > > - pcollection = pcollection.parallelDo("UnionCollectionWrapper", >>> > > > - (MapFn)IdentityFn.<Object>getInstance(), pcollection.getPType()); >>> > > > + pcollection = pcollection.parallelDo("UnionCollectionWrapper", >>> > > > + (MapFn) IdentityFn.<Object> getInstance(), pcollection.getPType()); >>> > > > } >>> > > > addOutput((PCollectionImpl<?>) pcollection, target); >>> > > > } >>> > > > >>> > > > private void addOutput(PCollectionImpl<?> impl, Target target) { >>> > > > if (!outputTargets.containsKey(impl)) { >>> > > > - outputTargets.put(impl, Sets.<Target>newHashSet()); >>> > > > + outputTargets.put(impl, Sets.<Target> newHashSet()); >>> > > > } >>> > > > outputTargets.get(impl).add(target); >>> > > > } >>> > > > - >>> > > > + >>> > > > @Override >>> > > > public <T> Iterable<T> materialize(PCollection<T> pcollection) { >>> > > > - >>> > > > - if (pcollection instanceof UnionCollection) { >>> > > > - pcollection = pcollection.parallelDo("UnionCollectionWrapper", >>> > > > - (MapFn)IdentityFn.<Object>getInstance(), pcollection.getPType()); >>> > > > - } >>> > > > - PCollectionImpl<T> impl = (PCollectionImpl<T>) pcollection; >>> > > > + >>> > > > + PCollectionImpl<T> pcollectionImpl = toPcollectionImpl(pcollection); >>> > > > + ReadableSourceTarget<T> srcTarget = >>> > > > getMaterializeSourceTarget(pcollectionImpl); >>> > > > + >>> > > > + MaterializableIterable<T> c = new MaterializableIterable<T>(this, >>> > > > srcTarget); >>> > > > + if (!outputTargetsToMaterialize.containsKey(pcollectionImpl)) { >>> > > > + outputTargetsToMaterialize.put(pcollectionImpl, c); >>> > > > + } >>> > > > + return c; >>> > > > + } >>> > > > + >>> > > > + /** >>> > > > + * Retrieve a ReadableSourceTarget that provides access to the >>> > > >>> > >>> > >>> > contents of a >>> > > > + * {@link PCollection}. This is primarily intended as a helper method >>> > > >>> > >>> > >>> > to >>> > > > + * {@link #materialize(PCollection)}. The underlying data of the >>> > > > + * ReadableSourceTarget may not be actually present until the >>> > > > pipeline is run. >>> > > > + * >>> > > > + * @param pcollection >>> > > > + * The collection for which the ReadableSourceTarget is to be >>> > > > + * retrieved >>> > > > + * @return The ReadableSourceTarget >>> > > > + * @throws IllegalArgumentException >>> > > > + * If no ReadableSourceTarget can be retrieved for the given >>> > > > + * PCollection >>> > > > + */ >>> > > > + public <T> ReadableSourceTarget<T> >>> > > > getMaterializeSourceTarget(PCollection<T> pcollection) { >>> > > > + PCollectionImpl<T> impl = toPcollectionImpl(pcollection); >>> > > > SourceTarget<T> matTarget = impl.getMaterializedAt(); >>> > > > if (matTarget != null && matTarget instanceof ReadableSourceTarget) { >>> > > > - return new MaterializableIterable<T>(this, >>> > > > (ReadableSourceTarget<T>) matTarget); >>> > > > + return (ReadableSourceTarget<T>) matTarget; >>> > > > + } >>> > > > + >>> > > > + ReadableSourceTarget<T> srcTarget = null; >>> > > > + if (outputTargets.containsKey(pcollection)) { >>> > > > + for (Target target : outputTargets.get(impl)) { >>> > > > + if (target instanceof ReadableSourceTarget) { >>> > > > + srcTarget = (ReadableSourceTarget<T>) target; >>> > > > + break; >>> > > > + } >>> > > > + } >>> > > > } >>> > > > - >>> > > > - ReadableSourceTarget<T> srcTarget = null; >>> > > > - if (outputTargets.containsKey(pcollection)) { >>> > > > - for (Target target : outputTargets.get(impl)) { >>> > > > - if (target instanceof ReadableSourceTarget) { >>> > > > - srcTarget = (ReadableSourceTarget) target; >>> > > > - break; >>> > > > - } >>> > > > - } >>> > > > - } >>> > > > - >>> > > > - if (srcTarget == null) { >>> > > > - SourceTarget<T> st = >>> > > >>> > >>> > >>> > createIntermediateOutput(pcollection.getPType()); >>> > > > - if (!(st instanceof ReadableSourceTarget)) { >>> > > > - throw new IllegalArgumentException("The PType for the given >>> > > > PCollection is not readable" >>> > > > - + " and cannot be materialized"); >>> > > > - } else { >>> > > > - srcTarget = (ReadableSourceTarget) st; >>> > > > - addOutput(impl, srcTarget); >>> > > > - } >>> > > > - } >>> > > > - >>> > > > - MaterializableIterable<T> c = new MaterializableIterable<T>(this, >>> > > >>> > >>> > >>> > srcTarget); >>> > > > - outputTargetsToMaterialize.put(impl, c); >>> > > > - return c; >>> > > > + >>> > > > + if (srcTarget == null) { >>> > > > + SourceTarget<T> st = >>> > > >>> > >>> > >>> > createIntermediateOutput(pcollection.getPType()); >>> > > > + if (!(st instanceof ReadableSourceTarget)) { >>> > > > + throw new IllegalArgumentException("The PType for the given >>> > > > PCollection is not readable" >>> > > > + + " and cannot be materialized"); >>> > > > + } else { >>> > > > + srcTarget = (ReadableSourceTarget<T>) st; >>> > > > + addOutput(impl, srcTarget); >>> > > > + } >>> > > > + } >>> > > > + >>> > > > + return srcTarget; >>> > > > + } >>> > > > + >>> > > > + /** >>> > > > + * Safely cast a PCollection into a PCollectionImpl, including >>> > > > handling the case of UnionCollections. >>> > > > + * @param pcollection The PCollection to be cast/transformed >>> > > > + * @return The PCollectionImpl representation >>> > > > + */ >>> > > > + private <T> PCollectionImpl<T> toPcollectionImpl(PCollection<T> >>> > > > pcollection) { >>> > > > + PCollectionImpl<T> pcollectionImpl = null; >>> > > > + if (pcollection instanceof UnionCollection) { >>> > > > + pcollectionImpl = (PCollectionImpl<T>) >>> > > > pcollection.parallelDo("UnionCollectionWrapper", >>> > > > + (MapFn) IdentityFn.<Object> getInstance(), pcollection.getPType()); >>> > > > + } else { >>> > > > + pcollectionImpl = (PCollectionImpl<T>) pcollection; >>> > > > + } >>> > > > + return pcollectionImpl; >>> > > > } >>> > > > >>> > > > public <T> SourceTarget<T> createIntermediateOutput(PType<T> ptype) { >>> > > > - return ptype.getDefaultFileSource(createTempPath()); >>> > > > + return ptype.getDefaultFileSource(createTempPath()); >>> > > > } >>> > > > >>> > > > public Path createTempPath() { >>> > > > tempFileIndex++; >>> > > > return new Path(tempDirectory, "p" + tempFileIndex); >>> > > > } >>> > > > - >>> > > > + >>> > > > private static Path createTempDirectory(Configuration conf) { >>> > > > Path dir = new Path("/tmp/crunch" + RANDOM.nextInt()); >>> > > > - try { >>> > > > - FileSystem.get(conf).mkdirs(dir); >>> > > > - } catch (IOException e) { >>> > > > - LOG.error("Exception creating job output directory", e); >>> > > > - throw new RuntimeException(e); >>> > > > - } >>> > > > + try { >>> > > > + FileSystem.get(conf).mkdirs(dir); >>> > > > + } catch (IOException e) { >>> > > > + LOG.error("Exception creating job output directory", e); >>> > > > + throw new RuntimeException(e); >>> > > > + } >>> > > > return dir; >>> > > > } >>> > > > - >>> > > > + >>> > > > @Override >>> > > > public <T> void writeTextFile(PCollection<T> pcollection, String >>> > > >>> > >>> > >>> > pathName) { >>> > > > // Ensure that this is a writable pcollection instance. >>> > > > - pcollection = pcollection.parallelDo("asText", >>> > > >>> > >>> > >>> > IdentityFn.<T>getInstance(), >>> > > > - WritableTypeFamily.getInstance().as(pcollection.getPType())); >>> > > > + pcollection = pcollection.parallelDo("asText", IdentityFn.<T> >>> > > > getInstance(), WritableTypeFamily >>> > > > + .getInstance().as(pcollection.getPType())); >>> > > > write(pcollection, At.textFile(pathName)); >>> > > > } >>> > > > >>> > > > @@ -256,7 +291,7 @@ public class MRPipeline implements Pipeline { >>> > > > LOG.info (http://LOG.info)("Exception during cleanup", e); >>> > > > } >>> > > > } >>> > > > - >>> > > > + >>> > > > public int getNextAnonymousStageId() { >>> > > > return nextAnonymousStageId++; >>> > > > } >>> > > > @@ -265,7 +300,7 @@ public class MRPipeline implements Pipeline { >>> > > > public void enableDebug() { >>> > > > // Turn on Crunch runtime error catching. >>> > > > getConfiguration().setBoolean(RuntimeParameters.DEBUG, true); >>> > > > - >>> > > > + >>> > > > // Write Hadoop's WARN logs to the console. >>> > > > Logger crunchInfoLogger = LogManager.getLogger("com.cloudera.crunch"); >>> > > > Appender console = crunchInfoLogger.getAppender("A"); >>> > > > @@ -277,9 +312,9 @@ public class MRPipeline implements Pipeline { >>> > > > LOG.warn("Could not find console appender named 'A' for writing >>> > > > Hadoop warning logs"); >>> > > > } >>> > > > } >>> > > > - >>> > > > + >>> > > > @Override >>> > > > public String getName() { >>> > > > - return name; >>> > > > + return name; >>> > > > } >>> > > > } >>> > > > diff --git >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/impl/mr/run/CrunchRuntimeException.java >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/impl/mr/run/CrunchRuntimeException.java >>> > > > index d41a52e..68ef054 100644 >>> > > > --- >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/impl/mr/run/CrunchRuntimeException.java >>> > > > +++ >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/impl/mr/run/CrunchRuntimeException.java >>> > > > @@ -12,6 +12,10 @@ public class CrunchRuntimeException extends >>> > > > RuntimeException { >>> > > > super(e); >>> > > > } >>> > > > >>> > > > + public CrunchRuntimeException(String msg, Exception e) { >>> > > > + super(msg, e); >>> > > > + } >>> > > > + >>> > > > public boolean wasLogged() { >>> > > > return logged; >>> > > > } >>> > > > diff --git >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/io/avro/AvroFileSource.java >>> > > > src/main/java/com/cloudera/crunch/io/avro/AvroFileSource.java >>> > > > index 1122d62..4debfeb 100644 >>> > > > --- src/main/java/com/cloudera/crunch/io/avro/AvroFileSource.java >>> > > > +++ src/main/java/com/cloudera/crunch/io/avro/AvroFileSource.java >>> > > > @@ -45,7 +45,8 @@ public class AvroFileSource<T> extends >>> > > > FileSourceImpl<T> implements ReadableSour >>> > > > >>> > > > @Override >>> > > > public Iterable<T> read(Configuration conf) throws IOException { >>> > > > - return CompositePathIterable.create(FileSystem.get(conf), path, >>> > > > new AvroFileReaderFactory<T>( >>> > > > + FileSystem fs = FileSystem.get(path.toUri(), conf); >>> > > > + return CompositePathIterable.create(fs, path, new >>> > > >>> > >>> > >>> > AvroFileReaderFactory<T>( >>> > > > (AvroType<T>) ptype, conf)); >>> > > > } >>> > > > } >>> > > > diff --git src/main/java/com/cloudera/crunch/io/seq/SeqFileSource.java >>> > > > src/main/java/com/cloudera/crunch/io/seq/SeqFileSource.java >>> > > > index 24dec2d..462ef93 100644 >>> > > > --- src/main/java/com/cloudera/crunch/io/seq/SeqFileSource.java >>> > > > +++ src/main/java/com/cloudera/crunch/io/seq/SeqFileSource.java >>> > > > @@ -26,18 +26,16 @@ import com.cloudera.crunch.io.ReadableSource; >>> > > > import com.cloudera.crunch.io.impl.FileSourceImpl; >>> > > > import com.cloudera.crunch.types.PType; >>> > > > >>> > > > -public class SeqFileSource<T> extends FileSourceImpl<T> implements >>> > > > - ReadableSource<T> { >>> > > > +public class SeqFileSource<T> extends FileSourceImpl<T> implements >>> > > > ReadableSource<T> { >>> > > > >>> > > > public SeqFileSource(Path path, PType<T> ptype) { >>> > > > - super(path, ptype, SequenceFileInputFormat.class); >>> > > > + super(path, ptype, SequenceFileInputFormat.class); >>> > > > } >>> > > > - >>> > > > + >>> > > > @Override >>> > > > public Iterable<T> read(Configuration conf) throws IOException { >>> > > > - FileSystem fs = FileSystem.get(conf); >>> > > > - return CompositePathIterable.create(fs, path, >>> > > > - new SeqFileReaderFactory<T>(ptype, conf)); >>> > > > + FileSystem fs = FileSystem.get(path.toUri(), conf); >>> > > > + return CompositePathIterable.create(fs, path, new >>> > > > SeqFileReaderFactory<T>(ptype, conf)); >>> > > > } >>> > > > >>> > > > @Override >>> > > > diff --git >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/io/seq/SeqFileTableSource.java >>> > > > src/main/java/com/cloudera/crunch/io/seq/SeqFileTableSource.java >>> > > > index 69ca12b..4db6658 100644 >>> > > > --- src/main/java/com/cloudera/crunch/io/seq/SeqFileTableSource.java >>> > > > +++ src/main/java/com/cloudera/crunch/io/seq/SeqFileTableSource.java >>> > > > @@ -42,7 +42,7 @@ public class SeqFileTableSource<K, V> extends >>> > > > FileTableSourceImpl<K, V> implemen >>> > > > >>> > > > @Override >>> > > > public Iterable<Pair<K, V>> read(Configuration conf) throws >>> > > >>> > >>> > >>> > IOException { >>> > > > - FileSystem fs = FileSystem.get(conf); >>> > > > + FileSystem fs = FileSystem.get(path.toUri(), conf); >>> > > > return CompositePathIterable.create(fs, path, >>> > > > new SeqFileTableReaderFactory<K, V>((PTableType<K, V>) ptype, conf)); >>> > > > } >>> > > > diff --git >>> > > >>> > >>> > >>> > src/main/java/com/cloudera/crunch/io/text/TextFileSource.java >>> > > > src/main/java/com/cloudera/crunch/io/text/TextFileSource.java >>> > > > index a876843..e0dbe68 100644 >>> > > > --- src/main/java/com/cloudera/crunch/io/text/TextFileSource.java >>> > > > +++ src/main/java/com/cloudera/crunch/io/text/TextFileSource.java >>> > > > @@ -67,7 +67,7 @@ public class TextFileSource<T> extends >>> > > > FileSourceImpl<T> implements >>> > > > >>> > > > @Override >>> > > > public Iterable<T> read(Configuration conf) throws IOException { >>> > > > - return CompositePathIterable.create(FileSystem.get(conf), path, >>> > > > - new TextFileReaderFactory<T>(ptype, conf)); >>> > > > + return CompositePathIterable.create(FileSystem.get(path.toUri(), >>> > > > conf), path, >>> > > > + new TextFileReaderFactory<T>(ptype, conf)); >>> > > > } >>> > > > } >>> > > > diff --git src/main/java/com/cloudera/crunch/lib/join/MapsideJoin.java >>> > > > src/main/java/com/cloudera/crunch/lib/join/MapsideJoin.java >>> > > > new file mode 100644 >>> > > > index 0000000..8072e07 >>> > > > --- /dev/null >>> > > > +++ src/main/java/com/cloudera/crunch/lib/join/MapsideJoin.java >>> > > > @@ -0,0 +1,143 @@ >>> > > > +package com.cloudera.crunch.lib.join; >>> > > > + >>> > > > +import java.io.IOException; >>> > > > + >>> > > > +import org.apache.hadoop.filecache.DistributedCache; >>> > > > +import org.apache.hadoop.fs.FileSystem; >>> > > > +import org.apache.hadoop.fs.Path; >>> > > > + >>> > > > +import com.cloudera.crunch.DoFn; >>> > > > +import com.cloudera.crunch.Emitter; >>> > > > +import com.cloudera.crunch.PTable; >>> > > > +import com.cloudera.crunch.Pair; >>> > > > +import com.cloudera.crunch.impl.mr.MRPipeline; >>> > > > +import com.cloudera.crunch.impl.mr.run.CrunchRuntimeException; >>> > > > +import com.cloudera.crunch.io.ReadableSourceTarget; >>> > > > +import com.cloudera.crunch.io.impl.SourcePathTargetImpl; >>> > > > +import com.cloudera.crunch.types.PType; >>> > > > +import com.cloudera.crunch.types.PTypeFamily; >>> > > > +import com.google.common.collect.ArrayListMultimap; >>> > > > +import com.google.common.collect.Multimap; >>> > > > + >>> > > > +/** >>> > > > + * Utility for doing map side joins on a common key between two >>> > > > {@link PTable}s. >>> > > > + * <p> >>> > > > + * A map side join is an optimized join which doesn't use a reducer; >>> > > >>> > >>> > >>> > instead, >>> > > > + * the right side of the join is loaded into memory and the join is >>> > > > performed in >>> > > > + * a mapper. This style of join has the important implication that >>> > > > the output of >>> > > > + * the join is not sorted, which is the case with a conventional >>> > > > (reducer-based) >>> > > > + * join. >>> > > > + * <p> >>> > > > + * <b>Note:</b>This utility is only supported when running with a >>> > > > + * {@link MRPipeline} as the pipeline. >>> > > > + */ >>> > > > +public class MapsideJoin { >>> > > > + >>> > > > + /** >>> > > > + * Join two tables using a map side join. The right-side table will >>> > > >>> > >>> > >>> > be loaded >>> > > > + * fully in memory, so this method should only be used if the right >>> > > >>> > >>> > >>> > side >>> > > > + * table's contents can fit in the memory allocated to mappers. The >>> > > >>> > >>> > >>> > join >>> > > > + * performed by this method is an inner join. >>> > > > + * >>> > > > + * @param left >>> > > > + * The left-side table of the join >>> > > > + * @param right >>> > > > + * The right-side table of the join, whose contents will be fully >>> > > > + * read into memory >>> > > > + * @return A table keyed on the join key, containing pairs of joined >>> > > >>> > >>> > >>> > values >>> > > > + */ >>> > > > + public static <K, U, V> PTable<K, Pair<U, V>> join(PTable<K, U> >>> > > > left, PTable<K, V> right) { >>> > > > + >>> > > > + if (!(right.getPipeline() instanceof MRPipeline)) { >>> > > > + throw new CrunchRuntimeException("Map-side join is only >>> > > > supported within a MapReduce context"); >>> > > > + } >>> > > > + >>> > > > + MRPipeline pipeline = (MRPipeline) right.getPipeline(); >>> > > > + pipeline.materialize(right); >>> > > > + >>> > > > + // TODO Move necessary logic to MRPipeline so that we can >>> > > >>> > >>> > >>> > theoretically >>> > > > + // optimize his by running the setup of multiple map-side joins >>> > > > concurrently >>> > > > + pipeline.run(); >>> > > > + >>> > > > + ReadableSourceTarget<Pair<K, V>> readableSourceTarget = pipeline >>> > > > + .getMaterializeSourceTarget(right); >>> > > > + if (!(readableSourceTarget instanceof SourcePathTargetImpl)) { >>> > > > + throw new CrunchRuntimeException("Right-side contents can't be >>> > > > read from a path"); >>> > > > + } >>> > > > + >>> > > > + // Suppress warnings because we've just checked this cast via >>> > > >>> > >>> > >>> > instanceof >>> > > > + @SuppressWarnings("unchecked") >>> > > > + SourcePathTargetImpl<Pair<K, V>> sourcePathTarget = >>> > > > (SourcePathTargetImpl<Pair<K, V>>) readableSourceTarget; >>> > > > + >>> > > > + Path path = sourcePathTarget.getPath(); >>> > > > + DistributedCache.addCacheFile(path.toUri(), >>> > > >>> > >>> > >>> > pipeline.getConfiguration()); >>> > > > + >>> > > > + MapsideJoinDoFn<K, U, V> mapJoinDoFn = new MapsideJoinDoFn<K, U, >>> > > > V>(path.toString(), >>> > > > + right.getPType()); >>> > > > + PTypeFamily typeFamily = left.getTypeFamily(); >>> > > > + return left.parallelDo( >>> > > > + "mapjoin", >>> > > > + mapJoinDoFn, >>> > > > + typeFamily.tableOf(left.getKeyType(), >>> > > > + typeFamily.pairs(left.getValueType(), right.getValueType()))); >>> > > > + >>> > > > + } >>> > > > + >>> > > > + static class MapsideJoinDoFn<K, U, V> extends DoFn<Pair<K, U>, >>> > > > Pair<K, Pair<U, V>>> { >>> > > > + >>> > > > + private String inputPath; >>> > > > + private PType<Pair<K, V>> ptype; >>> > > > + private Multimap<K, V> joinMap; >>> > > > + >>> > > > + public MapsideJoinDoFn(String inputPath, PType<Pair<K, V>> ptype) { >>> > > > + this.inputPath = inputPath; >>> > > > + this.ptype = ptype; >>> > > > + } >>> > > > + >>> > > > + private Path getCacheFilePath() { >>> > > > + try { >>> > > > + for (Path localPath : >>> > > > DistributedCache.getLocalCacheFiles(getConfiguration())) { >>> > > > + if (localPath.toString().endsWith(inputPath)) { >>> > > > + return >>> > > > localPath.makeQualified(FileSystem.getLocal(getConfiguration())); >>> > > > + >>> > > > + } >>> > > > + } >>> > > > + } catch (IOException e) { >>> > > > + throw new CrunchRuntimeException(e); >>> > > > + } >>> > > > + >>> > > > + throw new CrunchRuntimeException("Can't find local cache file >>> > > > for '" + inputPath + "'"); >>> > > > + } >>> > > > + >>> > > > + @Override >>> > > > + public void initialize() { >>> > > > + super.initialize(); >>> > > > + >>> > > > + ReadableSourceTarget<Pair<K, V>> sourceTarget = >>> > > > (ReadableSourceTarget<Pair<K, V>>) ptype >>> > > > + .getDefaultFileSource(getCacheFilePath()); >>> > > > + Iterable<Pair<K, V>> iterable = null; >>> > > > + try { >>> > > > + iterable = sourceTarget.read(getConfiguration()); >>> > > > + } catch (IOException e) { >>> > > > + throw new CrunchRuntimeException("Error reading right-side of >>> > > > map side join: ", e); >>> > > > + } >>> > > > + >>> > > > + joinMap = ArrayListMultimap.create(); >>> > > > + for (Pair<K, V> joinPair : iterable) { >>> > > > + joinMap.put(joinPair.first(), joinPair.second()); >>> > > > + } >>> > > > + } >>> > > > + >>> > > > + @Override >>> > > > + public void process(Pair<K, U> input, Emitter<Pair<K, Pair<U, >>> > > > V>>> emitter) { >>> > > > + K key = input.first(); >>> > > > + U value = input.second(); >>> > > > + for (V joinValue : joinMap.get(key)) { >>> > > > + Pair<U, V> valuePair = Pair.of(value, joinValue); >>> > > > + emitter.emit(Pair.of(key, valuePair)); >>> > > > + } >>> > > > + } >>> > > > + >>> > > > + } >>> > > > + >>> > > > +} >>> > > > diff --git src/main/java/com/cloudera/crunch/types/PType.java >>> > > > src/main/java/com/cloudera/crunch/types/PType.java >>> > > > index af4ef1b..ae480aa 100644 >>> > > > --- src/main/java/com/cloudera/crunch/types/PType.java >>> > > > +++ src/main/java/com/cloudera/crunch/types/PType.java >>> > > > @@ -15,6 +15,7 @@ >>> > > > >>> > > > package com.cloudera.crunch.types; >>> > > > >>> > > > +import java.io.Serializable; >>> > > > import java.util.List; >>> > > > >>> > > > import org.apache.hadoop.fs.Path; >>> > > > @@ -31,7 +32,7 @@ import com.cloudera.crunch.SourceTarget; >>> > > > * {@code PCollection}. >>> > > > * >>> > > > */ >>> > > > -public interface PType<T> { >>> > > > +public interface PType<T> extends Serializable { >>> > > > /** >>> > > > * Returns the Java type represented by this {@code PType}. >>> > > > */ >>> > > > diff --git src/main/java/com/cloudera/crunch/types/avro/AvroType.java >>> > > > src/main/java/com/cloudera/crunch/types/avro/AvroType.java >>> > > > index 3db00c0..29af9fb 100644 >>> > > > --- src/main/java/com/cloudera/crunch/types/avro/AvroType.java >>> > > > +++ src/main/java/com/cloudera/crunch/types/avro/AvroType.java >>> > > > @@ -14,6 +14,7 @@ >>> > > > */ >>> > > > package com.cloudera.crunch.types.avro; >>> > > > >>> > > > +import java.io.Serializable; >>> > > > import java.util.List; >>> > > > >>> > > > import org.apache.avro.Schema; >>> > > > @@ -41,7 +42,8 @@ public class AvroType<T> implements PType<T> { >>> > > > private static final Converter AVRO_CONVERTER = new >>> > > > AvroKeyConverter(); >>> > > > >>> > > > private final Class<T> typeClass; >>> > > > - private final Schema schema; >>> > > > + private final String schemaString; >>> > > > + private transient Schema schema; >>> > > > private final MapFn baseInputMapFn; >>> > > > private final MapFn baseOutputMapFn; >>> > > > private final List<PType> subTypes; >>> > > > @@ -55,6 +57,7 @@ public class AvroType<T> implements PType<T> { >>> > > > MapFn outputMapFn, PType... ptypes) { >>> > > > this.typeClass = typeClass; >>> > > > this.schema = Preconditions.checkNotNull(schema); >>> > > > + this.schemaString = schema.toString(); >>> > > > this.baseInputMapFn = inputMapFn; >>> > > > this.baseOutputMapFn = outputMapFn; >>> > > > this.subTypes = ImmutableList.<PType> builder().add(ptypes).build(); >>> > > > @@ -76,6 +79,9 @@ public class AvroType<T> implements PType<T> { >>> > > > } >>> > > > >>> > > > public Schema getSchema() { >>> > > > + if (schema == null){ >>> > > > + schema = new Schema.Parser().parse(schemaString); >>> > > > + } >>> > > > return schema; >>> > > > } >>> > > > >>> > > > diff --git >>> > src/test/java/com/cloudera/crunch/impl/mr/MRPipelineTest.java >>> > > > src/test/java/com/cloudera/crunch/impl/mr/MRPipelineTest.java >>> > > > new file mode 100644 >>> > > > index 0000000..f265460 >>> > > > --- /dev/null >>> > > > +++ src/test/java/com/cloudera/crunch/impl/mr/MRPipelineTest.java >>> > > > @@ -0,0 +1,60 @@ >>> > > > +package com.cloudera.crunch.impl.mr; >>> > > > + >>> > > > +import static org.junit.Assert.assertEquals; >>> > > > +import static org.mockito.Mockito.doReturn; >>> > > > +import static org.mockito.Mockito.mock; >>> > > > +import static org.mockito.Mockito.spy; >>> > > > +import static org.mockito.Mockito.when; >>> > > > + >>> > > > +import java.io.IOException; >>> > > > + >>> > > > +import org.junit.Before; >>> > > > +import org.junit.Test; >>> > > > + >>> > > > +import com.cloudera.crunch.SourceTarget; >>> > > > +import com.cloudera.crunch.impl.mr.collect.PCollectionImpl; >>> > > > +import com.cloudera.crunch.io.ReadableSourceTarget; >>> > > > +import com.cloudera.crunch.types.avro.Avros; >>> > > > + >>> > > > +public class MRPipelineTest { >>> > > > + >>> > > > + private MRPipeline pipeline; >>> > > > + >>> > > > + @Before >>> > > > + public void setUp() throws IOException { >>> > > > + pipeline = spy(new MRPipeline(MRPipelineTest.class)); >>> > > > + } >>> > > > + >>> > > > + @Test >>> > > > + public void testGetMaterializeSourceTarget_AlreadyMaterialized() { >>> > > > + PCollectionImpl<String> materializedPcollection = >>> > > > mock(PCollectionImpl.class); >>> > > > + ReadableSourceTarget<String> readableSourceTarget = >>> > > > mock(ReadableSourceTarget.class); >>> > > > + >>> > > >>> > >>> > >>> > when(materializedPcollection.getMaterializedAt()).thenReturn(readableSourceTarget); >>> > > > + >>> > > > + assertEquals(readableSourceTarget, >>> > > > pipeline.getMaterializeSourceTarget(materializedPcollection)); >>> > > > + } >>> > > > + >>> > > > + @Test >>> > > > + public void >>> > > >>> > >>> > >>> > testGetMaterializeSourceTarget_NotMaterialized_HasOutput() { >>> > > > + >>> > > > + PCollectionImpl<String> pcollection = mock(PCollectionImpl.class); >>> > > > + ReadableSourceTarget<String> readableSourceTarget = >>> > > > mock(ReadableSourceTarget.class); >>> > > > + when(pcollection.getPType()).thenReturn(Avros.strings()); >>> > > > + >>> > > >>> > >>> > >>> > doReturn(readableSourceTarget).when(pipeline).createIntermediateOutput(Avros.strings()); >>> > > > + when(pcollection.getMaterializedAt()).thenReturn(null); >>> > > > + >>> > > > + assertEquals(readableSourceTarget, >>> > > > pipeline.getMaterializeSourceTarget(pcollection)); >>> > > > + } >>> > > > + >>> > > > + @Test(expected = IllegalArgumentException.class) >>> > > > + public void >>> > > >>> > >>> > >>> > testGetMaterializeSourceTarget_NotMaterialized_NotReadableSourceTarget() >>> > > > { >>> > > > + PCollectionImpl<String> pcollection = mock(PCollectionImpl.class); >>> > > > + SourceTarget<String> nonReadableSourceTarget = >>> > > >>> > >>> > >>> > mock(SourceTarget.class); >>> > > > + when(pcollection.getPType()).thenReturn(Avros.strings()); >>> > > > + >>> > > >>> > >>> > >>> > doReturn(nonReadableSourceTarget).when(pipeline).createIntermediateOutput(Avros.strings()); >>> > > > + when(pcollection.getMaterializedAt()).thenReturn(null); >>> > > > + >>> > > > + pipeline.getMaterializeSourceTarget(pcollection); >>> > > > + } >>> > > > + >>> > > > +} >>> > > > diff --git >>> > > >>> > >>> > >>> > src/test/java/com/cloudera/crunch/lib/join/MapsideJoinTest.java >>> > > > src/test/java/com/cloudera/crunch/lib/join/MapsideJoinTest.java >>> > > > new file mode 100644 >>> > > > index 0000000..97e0c63 >>> > > > --- /dev/null >>> > > > +++ src/test/java/com/cloudera/crunch/lib/join/MapsideJoinTest.java >>> > > > @@ -0,0 +1,102 @@ >>> > > > +package com.cloudera.crunch.lib.join; >>> > > > + >>> > > > +import static org.junit.Assert.assertEquals; >>> > > > +import static org.junit.Assert.assertTrue; >>> > > > + >>> > > > +import java.io.IOException; >>> > > > +import java.util.Collections; >>> > > > +import java.util.List; >>> > > > + >>> > > > +import org.junit.Test; >>> > > > + >>> > > > +import com.cloudera.crunch.FilterFn; >>> > > > +import com.cloudera.crunch.MapFn; >>> > > > +import com.cloudera.crunch.PTable; >>> > > > +import com.cloudera.crunch.Pair; >>> > > > +import com.cloudera.crunch.Pipeline; >>> > > > +import com.cloudera.crunch.impl.mem.MemPipeline; >>> > > > +import com.cloudera.crunch.impl.mr.MRPipeline; >>> > > > +import com.cloudera.crunch.impl.mr.run.CrunchRuntimeException; >>> > > > +import com.cloudera.crunch.test.FileHelper; >>> > > > +import com.cloudera.crunch.types.writable.Writables; >>> > > > +import com.google.common.collect.Lists; >>> > > > + >>> > > > +public class MapsideJoinTest { >>> > > > + >>> > > > + private static class LineSplitter extends MapFn<String, >>> > > > Pair<Integer, String>> { >>> > > > + >>> > > > + @Override >>> > > > + public Pair<Integer, String> map(String input) { >>> > > > + String[] fields = input.split("\\|"); >>> > > > + return Pair.of(Integer.parseInt(fields[0]), fields[1]); >>> > > > + } >>> > > > + >>> > > > + } >>> > > > + >>> > > > + private static class NegativeFilter extends FilterFn<Pair<Integer, >>> > > >>> > >>> > >>> > String>> { >>> > > > + >>> > > > + @Override >>> > > > + public boolean accept(Pair<Integer, String> input) { >>> > > > + return false; >>> > > > + } >>> > > > + >>> > > > + } >>> > > > + >>> > > > + @Test(expected = CrunchRuntimeException.class) >>> > > > + public void testNonMapReducePipeline() { >>> > > > + runMapsideJoin(MemPipeline.getInstance()); >>> > > > + } >>> > > > + >>> > > > + @Test >>> > > > + public void testMapsideJoin_RightSideIsEmpty() throws IOException { >>> > > > + MRPipeline pipeline = new MRPipeline(MapsideJoinTest.class); >>> > > > + PTable<Integer, String> customerTable = readTable(pipeline, >>> > > > "customers.txt"); >>> > > > + PTable<Integer, String> orderTable = readTable(pipeline, >>> > > >>> > >>> > >>> > "orders.txt"); >>> > > > + >>> > > > + PTable<Integer, String> filteredOrderTable = >>> > > > orderTable.parallelDo(new NegativeFilter(), >>> > > > + orderTable.getPTableType()); >>> > > > + >>> > > > + PTable<Integer, Pair<String, String>> joined = >>> > > > MapsideJoin.join(customerTable, >>> > > > + filteredOrderTable); >>> > > > + >>> > > > + List<Pair<Integer, Pair<String, String>>> materializedJoin = >>> > > > Lists.newArrayList(joined >>> > > > + .materialize()); >>> > > > + >>> > > > + assertTrue(materializedJoin.isEmpty()); >>> > > > + >>> > > > + } >>> > > > + >>> > > > + @Test >>> > > > + public void testMapsideJoin() throws IOException { >>> > > > + runMapsideJoin(new MRPipeline(MapsideJoinTest.class)); >>> > > > + } >>> > > > + >>> > > > + private void runMapsideJoin(Pipeline pipeline) { >>> > > > + PTable<Integer, String> customerTable = readTable(pipeline, >>> > > > "customers.txt"); >>> > > > + PTable<Integer, String> orderTable = readTable(pipeline, >>> > > >>> > >>> > >>> > "orders.txt"); >>> > > > + >>> > > > + PTable<Integer, Pair<String, String>> joined = >>> > > > MapsideJoin.join(customerTable, orderTable); >>> > > > + >>> > > > + List<Pair<Integer, Pair<String, String>>> expectedJoinResult = >>> > > > Lists.newArrayList(); >>> > > > + expectedJoinResult.add(Pair.of(111, Pair.of("John Doe", "Corn >>> > > >>> > >>> > >>> > flakes"))); >>> > > > + expectedJoinResult.add(Pair.of(222, Pair.of("Jane Doe", "Toilet >>> > > >>> > >>> > >>> > paper"))); >>> > > > + expectedJoinResult.add(Pair.of(222, Pair.of("Jane Doe", "Toilet >>> > > > plunger"))); >>> > > > + expectedJoinResult.add(Pair.of(333, Pair.of("Someone Else", >>> > > > "Toilet brush"))); >>> > > > + >>> > > > + List<Pair<Integer, Pair<String, String>>> joinedResultList = >>> > > > Lists.newArrayList(joined >>> > > > + .materialize()); >>> > > > + Collections.sort(joinedResultList); >>> > > > + >>> > > > + assertEquals(expectedJoinResult, joinedResultList); >>> > > > + } >>> > > > + >>> > > > + private static PTable<Integer, String> readTable(Pipeline pipeline, >>> > > > String filename) { >>> > > > + try { >>> > > > + return >>> > > >>> > >>> > >>> > pipeline.readTextFile(FileHelper.createTempCopyOf(filename)).parallelDo("asTable", >>> > > > + new LineSplitter(), Writables.tableOf(Writables.ints(), >>> > > > Writables.strings())); >>> > > > + } catch (IOException e) { >>> > > > + throw new RuntimeException(e); >>> > > > + } >>> > > > + } >>> > > > + >>> > > > +} >>> > > > diff --git src/test/java/com/cloudera/crunch/types/avro/AvrosTest.java >>> > > > src/test/java/com/cloudera/crunch/types/avro/AvrosTest.java >>> > > > index 74e2ad3..c6a0b46 100644 >>> > > > --- src/test/java/com/cloudera/crunch/types/avro/AvrosTest.java >>> > > > +++ src/test/java/com/cloudera/crunch/types/avro/AvrosTest.java >>> > > > @@ -25,6 +25,7 @@ import org.apache.avro.Schema.Type; >>> > > > import org.apache.avro.generic.GenericData; >>> > > > import org.apache.avro.util.Utf8; >>> > > > import org.apache.hadoop.io.LongWritable; >>> > > > +import org.junit.Ignore; >>> > > > import org.junit.Test; >>> > > > >>> > > > import com.cloudera.crunch.Pair; >>> > > > @@ -103,6 +104,7 @@ public class AvrosTest { >>> > > > } >>> > > > >>> > > > @Test >>> > > > + @Ignore("This test creates an invalid schema that causes >>> > > > Schema#toString to fail") >>> > > > public void testNestedTables() throws Exception { >>> > > > PTableType<Long, Long> pll = Avros.tableOf(Avros.longs(), >>> > > >>> > >>> > >>> > Avros.longs()); >>> > > > PTableType<Pair<Long, Long>, String> nest = Avros.tableOf(pll, >>> > > > Avros.strings()); >>> > > > diff --git src/test/resources/customers.txt >>> > > >>> > >>> > >>> > src/test/resources/customers.txt >>> > > > new file mode 100644 >>> > > > index 0000000..98f3f3d >>> > > > --- /dev/null >>> > > > +++ src/test/resources/customers.txt >>> > > > @@ -0,0 +1,4 @@ >>> > > > +111|John Doe >>> > > > +222|Jane Doe >>> > > > +333|Someone Else >>> > > > +444|Has No Orders >>> > > > \ No newline at end of file >>> > > > diff --git src/test/resources/orders.txt src/test/resources/orders.txt >>> > > > new file mode 100644 >>> > > > index 0000000..2f1383f >>> > > > --- /dev/null >>> > > > +++ src/test/resources/orders.txt >>> > > > @@ -0,0 +1,4 @@ >>> > > > +222|Toilet plunger >>> > > > +333|Toilet brush >>> > > > +222|Toilet paper >>> > > > +111|Corn flakes >>> > > > \ No newline at end of file >>> > > > >>> > > > >>> > > > >>> > > > On Tue, Jul 3, 2012 at 10:42 AM, Christian Tzolov >>> > > > <[email protected] (mailto:[email protected])> >>> > > >>> > >>> > >>> > wrote: >>> > > > > Hi Gabriel, >>> > > > > >>> > > > > Seems like the attachment is missing. >>> > > > > >>> > > > > Cheers, >>> > > > > Chris >>> > > > > >>> > > > > On Tue, Jul 3, 2012 at 9:23 AM, Gabriel Reid >>> > > > > <[email protected] (mailto:[email protected])(mailto: >>> > [email protected] (mailto:[email protected]))> wrote: >>> > > > > >>> > > > > > Hi guys, >>> > > > > > >>> > > > > > Attached (hopefully) is a patch for an initial implementation of >>> > map >>> > > > > > side joins. It's currently implemented as a static method in a >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > class >>> > > > > > called MapsideJoin, with the same interface as the existing Join >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > class >>> > > > > > (with only inner joins being implemented for now). The way it >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > works is >>> > > > > > that the right-side PTable of the join is put in the distributed >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > cache >>> > > > > > and then read by the join function at runtime. >>> > > > > > >>> > > > > > There's one spot that I can see for a potentially interesting >>> > > > > > optimization -- MRPipeline#run is called once for each map side >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > join >>> > > > > > that is set up, but if the setup of the joins was done within >>> > > > > > MRPipeline, then we could set up multiple map side joins in >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > parallel >>> > > > > > with a single call to MRPipeline#run. OTOH, a whole bunch of map >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > side >>> > > > > > joins in parallel probably isn't that common of an operation. >>> > > > > > >>> > > > > > If anyone feels like taking a look at the patch, any feedback is >>> > > > > > appreciated. If nobody sees something that needs serious changes >>> > > > > > in >>> > > > > > the patch, I'll commit it. >>> > > > > > >>> > > > > > - Gabriel >>> > > > > > >>> > > > > > >>> > > > > > On Thu, Jun 21, 2012 at 9:09 AM, Gabriel Reid < >>> > [email protected] (mailto:[email protected])> >>> > > > > > wrote: >>> > > > > > > Replying to all... >>> > > > > > > >>> > > > > > > On Thu, Jun 21, 2012 at 8:40 AM, Josh Wills >>> > > > > > > <[email protected] (mailto:[email protected])(mailto: >>> > [email protected] (mailto:[email protected]))> wrote: >>> > > > > > > > >>> > > > > > > > So there's a philosophical issue here: should Crunch ever make >>> > > > > > > > decisions about how to do something itself based on its >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > estimates of >>> > > > > > > > the size of the data sets, or should it always do exactly what >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > the >>> > > > > > > > developer indicates? >>> > > > > > > > >>> > > > > > > > I can make a case either way, but I think that no matter what, >>> > we >>> > > > > > > > would want to have explicit functions for performing a join >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > that reads >>> > > > > > > > one data set into memory, so I think we can proceed w/the >>> > > > > > > > implementation while folks weigh in on what their preferences >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > are for >>> > > > > > > > the default join() behavior (e.g., just do a reduce-side join, >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > or try >>> > > > > > > > to figure out the best join given information about the input >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > data and >>> > > > > > > > some configuration parameters.) >>> > > > > > > >>> > > > > > > >>> > > > > > > >>> > > > > > > >>> > > > > > > >>> > > > > > > I definitely agree on needing to have an explicit way to invoke >>> > one or >>> > > > > > > the other -- and in general I don't like having magic behind the >>> > > > > > > scenes to decide on behaviour (especially considering Crunch is >>> > > > > > > generally intended to be closer to the metal than Pig and Hive). >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > I'm >>> > > > > > > not sure if the runtime decision is something specific to some >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > of my >>> > > > > > > use cases or if it could be useful to a wider audience. >>> > > > > > > >>> > > > > > > The ability to dynamically decide at runtime whether a map side >>> > join >>> > > > > > > should be used can also easily be tacked on outside of Crunch, >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > and >>> > > > > > > won't impact the underlying implementation (as you pointed out), >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > so I >>> > > > > > > definitely also agree on focusing on the underlying >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > implementation >>> > > > > > > first, and we can worry about the options used for exposing it >>> > > > > > >>> > > > > >>> > > > >>> > > >>> > >>> > >>> > later >>> > > > > > > on. >>> > > > > > > >>> > > > > > > - Gabriel >>> >>> >>> -- >>> Director of Data Science >>> Cloudera <http://www.cloudera.com> >>> Twitter: @josh_wills <http://twitter.com/josh_wills> >> >> >>
