Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.drill.exec.physical.impl.TopN; import java.io.IOException; import java.util.Iterator; import java.util.List; import java.util.concurrent.TimeUnit; import org.apache.drill.common.expression.ErrorCollector; import org.apache.drill.common.expression.ErrorCollectorImpl; import org.apache.drill.common.expression.LogicalExpression; import org.apache.drill.common.expression.SchemaPath; import org.apache.drill.common.logical.data.Order.Ordering; import org.apache.drill.exec.ExecConstants; import org.apache.drill.exec.compile.sig.MappingSet; import org.apache.drill.exec.exception.ClassTransformationException; import org.apache.drill.exec.exception.SchemaChangeException; import org.apache.drill.exec.expr.ClassGenerator; import org.apache.drill.exec.expr.ClassGenerator.HoldingContainer; import org.apache.drill.exec.expr.CodeGenerator; import org.apache.drill.exec.expr.ExpressionTreeMaterializer; import org.apache.drill.exec.expr.TypeHelper; import org.apache.drill.exec.expr.fn.FunctionGenerationHelper; import org.apache.drill.exec.memory.OutOfMemoryException; import org.apache.drill.exec.ops.FragmentContext; import org.apache.drill.exec.physical.config.TopN; import org.apache.drill.exec.physical.impl.sort.RecordBatchData; import org.apache.drill.exec.physical.impl.sort.SortRecordBatchBuilder; import org.apache.drill.exec.physical.impl.svremover.Copier; import org.apache.drill.exec.physical.impl.svremover.RemovingRecordBatch; import org.apache.drill.exec.record.AbstractRecordBatch; import org.apache.drill.exec.record.BatchSchema; import org.apache.drill.exec.record.BatchSchema.SelectionVectorMode; import org.apache.drill.exec.record.ExpandableHyperContainer; import org.apache.drill.exec.record.RecordBatch; import org.apache.drill.exec.record.TypedFieldId; import org.apache.drill.exec.record.VectorAccessible; import org.apache.drill.exec.record.VectorContainer; import org.apache.drill.exec.record.VectorWrapper; import org.apache.drill.exec.record.WritableBatch; import org.apache.drill.exec.record.selection.SelectionVector2; import org.apache.drill.exec.record.selection.SelectionVector4; import org.apache.drill.exec.vector.ValueVector; import org.apache.drill.exec.vector.complex.AbstractContainerVector; import org.apache.calcite.rel.RelFieldCollation.Direction; import com.google.common.base.Stopwatch; import com.sun.codemodel.JConditional; import com.sun.codemodel.JExpr; public class TopNBatch extends AbstractRecordBatch<TopN> { static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(TopNBatch.class); private static final long MAX_SORT_BYTES = 1L * 1024 * 1024 * 1024; private final int batchPurgeThreshold; public final MappingSet MAIN_MAPPING = new MappingSet((String) null, null, ClassGenerator.DEFAULT_SCALAR_MAP, ClassGenerator.DEFAULT_SCALAR_MAP); public final MappingSet LEFT_MAPPING = new MappingSet("leftIndex", null, ClassGenerator.DEFAULT_SCALAR_MAP, ClassGenerator.DEFAULT_SCALAR_MAP); public final MappingSet RIGHT_MAPPING = new MappingSet("rightIndex", null, ClassGenerator.DEFAULT_SCALAR_MAP, ClassGenerator.DEFAULT_SCALAR_MAP); private final RecordBatch incoming; private BatchSchema schema; private PriorityQueue priorityQueue; private TopN config; SelectionVector4 sv4; private long countSincePurge; private int batchCount; private Copier copier; private boolean first = true; private int recordCount = 0; public TopNBatch(TopN popConfig, FragmentContext context, RecordBatch incoming) throws OutOfMemoryException { super(popConfig, context); this.incoming = incoming; this.config = popConfig; batchPurgeThreshold = context.getConfig().getInt(ExecConstants.BATCH_PURGE_THRESHOLD); } @Override public int getRecordCount() { return recordCount; } @Override public SelectionVector2 getSelectionVector2() { throw new UnsupportedOperationException(); } @Override public SelectionVector4 getSelectionVector4() { return sv4; } @Override public void close() { if (sv4 != null) { sv4.clear(); } if (priorityQueue != null) { priorityQueue.cleanup(); } super.close(); } @Override public void buildSchema() throws SchemaChangeException { VectorContainer c = new VectorContainer(oContext); IterOutcome outcome = next(incoming); switch (outcome) { case OK: case OK_NEW_SCHEMA: for (VectorWrapper w : incoming) { ValueVector v = c.addOrGet(w.getField()); if (v instanceof AbstractContainerVector) { w.getValueVector().makeTransferPair(v); v.clear(); } } c = VectorContainer.canonicalize(c); for (VectorWrapper w : c) { ValueVector v = container.addOrGet(w.getField()); if (v instanceof AbstractContainerVector) { w.getValueVector().makeTransferPair(v); v.clear(); } v.allocateNew(); } container.buildSchema(SelectionVectorMode.NONE); container.setRecordCount(0); return; case STOP: state = BatchState.STOP; return; case OUT_OF_MEMORY: state = BatchState.OUT_OF_MEMORY; return; case NONE: state = BatchState.DONE; default: return; } } @Override public IterOutcome innerNext() { if (state == BatchState.DONE) { return IterOutcome.NONE; } if (schema != null) { if (getSelectionVector4().next()) { recordCount = sv4.getCount(); return IterOutcome.OK; } else { recordCount = 0; return IterOutcome.NONE; } } try { outer: while (true) { Stopwatch watch = new Stopwatch(); watch.start(); IterOutcome upstream; if (first) { upstream = IterOutcome.OK_NEW_SCHEMA; first = false; } else { upstream = next(incoming); } if (upstream == IterOutcome.OK && schema == null) { upstream = IterOutcome.OK_NEW_SCHEMA; container.clear(); } logger.debug("Took {} us to get next", watch.elapsed(TimeUnit.MICROSECONDS)); switch (upstream) { case NONE: break outer; case NOT_YET: throw new UnsupportedOperationException(); case OUT_OF_MEMORY: case STOP: return upstream; case OK_NEW_SCHEMA: // only change in the case that the schema truly changes. Artificial schema changes are ignored. if (!incoming.getSchema().equals(schema)) { if (schema != null) { throw new UnsupportedOperationException( "Sort doesn't currently support sorts with changing schemas."); } this.schema = incoming.getSchema(); } // fall through. case OK: if (incoming.getRecordCount() == 0) { for (VectorWrapper w : incoming) { w.clear(); } break; } countSincePurge += incoming.getRecordCount(); batchCount++; RecordBatchData batch = new RecordBatchData(incoming); boolean success = false; try { batch.canonicalize(); if (priorityQueue == null) { priorityQueue = createNewPriorityQueue(context, config.getOrderings(), new ExpandableHyperContainer(batch.getContainer()), MAIN_MAPPING, LEFT_MAPPING, RIGHT_MAPPING); } priorityQueue.add(context, batch); if (countSincePurge > config.getLimit() && batchCount > batchPurgeThreshold) { purge(); countSincePurge = 0; batchCount = 0; } success = true; } finally { if (!success) { batch.clear(); } } break; default: throw new UnsupportedOperationException(); } } if (schema == null || priorityQueue == null) { // builder may be null at this point if the first incoming batch is empty state = BatchState.DONE; return IterOutcome.NONE; } priorityQueue.generate(); this.sv4 = priorityQueue.getFinalSv4(); container.clear(); for (VectorWrapper w : priorityQueue.getHyperBatch()) { container.add(w.getValueVectors()); } container.buildSchema(BatchSchema.SelectionVectorMode.FOUR_BYTE); recordCount = sv4.getCount(); return IterOutcome.OK_NEW_SCHEMA; } catch (SchemaChangeException | ClassTransformationException | IOException ex) { kill(false); logger.error("Failure during query", ex); context.fail(ex); return IterOutcome.STOP; } } private void purge() throws SchemaChangeException { Stopwatch watch = new Stopwatch(); watch.start(); VectorContainer c = priorityQueue.getHyperBatch(); VectorContainer newContainer = new VectorContainer(oContext); SelectionVector4 selectionVector4 = priorityQueue.getHeapSv4(); SimpleRecordBatch batch = new SimpleRecordBatch(c, selectionVector4, context); SimpleRecordBatch newBatch = new SimpleRecordBatch(newContainer, null, context); if (copier == null) { copier = RemovingRecordBatch.getGenerated4Copier(batch, context, oContext.getAllocator(), newContainer, newBatch, null); } else { for (VectorWrapper<?> i : batch) { ValueVector v = TypeHelper.getNewVector(i.getField(), oContext.getAllocator()); newContainer.add(v); } copier.setupRemover(context, batch, newBatch); } SortRecordBatchBuilder builder = new SortRecordBatchBuilder(oContext.getAllocator(), MAX_SORT_BYTES); try { do { int count = selectionVector4.getCount(); int copiedRecords = copier.copyRecords(0, count); assert copiedRecords == count; for (VectorWrapper<?> v : newContainer) { ValueVector.Mutator m = v.getValueVector().getMutator(); m.setValueCount(count); } newContainer.buildSchema(BatchSchema.SelectionVectorMode.NONE); newContainer.setRecordCount(count); builder.add(newBatch); } while (selectionVector4.next()); selectionVector4.clear(); c.clear(); VectorContainer newQueue = new VectorContainer(); builder.canonicalize(); builder.build(context, newQueue); priorityQueue.resetQueue(newQueue, builder.getSv4().createNewWrapperCurrent()); builder.getSv4().clear(); selectionVector4.clear(); } finally { builder.close(); } logger.debug("Took {} us to purge", watch.elapsed(TimeUnit.MICROSECONDS)); } public PriorityQueue createNewPriorityQueue(FragmentContext context, List<Ordering> orderings, VectorAccessible batch, MappingSet mainMapping, MappingSet leftMapping, MappingSet rightMapping) throws ClassTransformationException, IOException, SchemaChangeException { CodeGenerator<PriorityQueue> cg = CodeGenerator.get(PriorityQueue.TEMPLATE_DEFINITION, context.getFunctionRegistry()); ClassGenerator<PriorityQueue> g = cg.getRoot(); g.setMappingSet(mainMapping); for (Ordering od : orderings) { // first, we rewrite the evaluation stack for each side of the comparison. ErrorCollector collector = new ErrorCollectorImpl(); final LogicalExpression expr = ExpressionTreeMaterializer.materialize(od.getExpr(), batch, collector, context.getFunctionRegistry()); if (collector.hasErrors()) { throw new SchemaChangeException( "Failure while materializing expression. " + collector.toErrorString()); } g.setMappingSet(leftMapping); HoldingContainer left = g.addExpr(expr, false); g.setMappingSet(rightMapping); HoldingContainer right = g.addExpr(expr, false); g.setMappingSet(mainMapping); // next we wrap the two comparison sides and add the expression block for the comparison. LogicalExpression fh = FunctionGenerationHelper.getOrderingComparator(od.nullsSortHigh(), left, right, context.getFunctionRegistry()); HoldingContainer out = g.addExpr(fh, false); JConditional jc = g.getEvalBlock()._if(out.getValue().ne(JExpr.lit(0))); if (od.getDirection() == Direction.ASCENDING) { jc._then()._return(out.getValue()); } else { jc._then()._return(out.getValue().minus()); } g.rotateBlock(); } g.rotateBlock(); g.getEvalBlock()._return(JExpr.lit(0)); PriorityQueue q = context.getImplementationClass(cg); q.init(config.getLimit(), context, oContext.getAllocator(), schema.getSelectionVectorMode() == BatchSchema.SelectionVectorMode.TWO_BYTE); return q; } @Override public WritableBatch getWritableBatch() { throw new UnsupportedOperationException("A sort batch is not writable."); } @Override protected void killIncoming(boolean sendUpstream) { incoming.kill(sendUpstream); } public static class SimpleRecordBatch implements RecordBatch { private VectorContainer container; private SelectionVector4 sv4; private FragmentContext context; public SimpleRecordBatch(VectorContainer container, SelectionVector4 sv4, FragmentContext context) { this.container = container; this.sv4 = sv4; this.context = context; } @Override public FragmentContext getContext() { return context; } @Override public BatchSchema getSchema() { return container.getSchema(); } @Override public int getRecordCount() { if (sv4 != null) { return sv4.getCount(); } else { return container.getRecordCount(); } } @Override public void kill(boolean sendUpstream) { } @Override public SelectionVector2 getSelectionVector2() { throw new UnsupportedOperationException(); } @Override public SelectionVector4 getSelectionVector4() { return sv4; } @Override public TypedFieldId getValueVectorId(SchemaPath path) { return container.getValueVectorId(path); } @Override public VectorWrapper<?> getValueAccessorById(Class<?> clazz, int... ids) { return container.getValueAccessorById(clazz, ids); } @Override public IterOutcome next() { throw new UnsupportedOperationException(); } @Override public WritableBatch getWritableBatch() { throw new UnsupportedOperationException(); } @Override public Iterator<VectorWrapper<?>> iterator() { return container.iterator(); } @Override public VectorContainer getOutgoingContainer() { throw new UnsupportedOperationException( String.format(" You should not call getOutgoingContainer() for class %s", this.getClass().getCanonicalName())); } } }