/**
* Creates a copier that does a project for every Nth record from a VectorContainer incoming into
* VectorContainer outgoing. Each Ordering in orderings generates a column, and evaluation of the
* expression associated with each Ordering determines the value of each column. These records
* will later be sorted based on the values in each column, in the same order as the orderings.
*
* @param sv4
* @param incoming
* @param outgoing
* @param orderings
* @return
* @throws SchemaChangeException
*/
private SampleCopier getCopier(
SelectionVector4 sv4,
VectorContainer incoming,
VectorContainer outgoing,
List<Ordering> orderings,
List<ValueVector> localAllocationVectors)
throws SchemaChangeException {
final ErrorCollector collector = new ErrorCollectorImpl();
final ClassGenerator<SampleCopier> cg =
CodeGenerator.getRoot(SampleCopier.TEMPLATE_DEFINITION, context.getFunctionRegistry());
int i = 0;
for (Ordering od : orderings) {
final LogicalExpression expr =
ExpressionTreeMaterializer.materialize(
od.getExpr(), incoming, collector, context.getFunctionRegistry());
SchemaPath schemaPath = SchemaPath.getSimplePath("f" + i++);
TypeProtos.MajorType.Builder builder =
TypeProtos.MajorType.newBuilder()
.mergeFrom(expr.getMajorType())
.clearMode()
.setMode(TypeProtos.DataMode.REQUIRED);
TypeProtos.MajorType newType = builder.build();
MaterializedField outputField = MaterializedField.create(schemaPath, newType);
if (collector.hasErrors()) {
throw new SchemaChangeException(
String.format(
"Failure while trying to materialize incoming schema. Errors:\n %s.",
collector.toErrorString()));
}
ValueVector vector = TypeHelper.getNewVector(outputField, oContext.getAllocator());
localAllocationVectors.add(vector);
TypedFieldId fid = outgoing.add(vector);
ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, true);
HoldingContainer hc = cg.addExpr(write);
cg.getEvalBlock()._if(hc.getValue().eq(JExpr.lit(0)))._then()._return(JExpr.FALSE);
}
cg.rotateBlock();
cg.getEvalBlock()._return(JExpr.TRUE);
outgoing.buildSchema(BatchSchema.SelectionVectorMode.NONE);
try {
SampleCopier sampleCopier = context.getImplementationClass(cg);
sampleCopier.setupCopier(context, sv4, incoming, outgoing);
return sampleCopier;
} catch (ClassTransformationException | IOException e) {
throw new SchemaChangeException(e);
}
}
private VectorContainer constructHyperBatch(List<BatchGroup> batchGroupList) {
VectorContainer cont = new VectorContainer();
for (MaterializedField field : schema) {
ValueVector[] vectors = new ValueVector[batchGroupList.size()];
int i = 0;
for (BatchGroup group : batchGroupList) {
vectors[i++] =
group
.getValueAccessorById(
field.getValueClass(),
group.getValueVectorId(SchemaPath.getSimplePath(field.getPath())).getFieldIds())
.getValueVector();
}
cont.add(vectors);
}
cont.buildSchema(BatchSchema.SelectionVectorMode.FOUR_BYTE);
return cont;
}
@Override
public void setNewSchema() throws SchemaChangeException {
container.buildSchema(SelectionVectorMode.NONE);
}
public BatchGroup mergeAndSpill(LinkedList<BatchGroup> batchGroups) throws SchemaChangeException {
logger.debug("Copier allocator current allocation {}", copierAllocator.getAllocatedMemory());
logger.debug(
"mergeAndSpill: starting total size in memory = {}", oAllocator.getAllocatedMemory());
VectorContainer outputContainer = new VectorContainer();
List<BatchGroup> batchGroupList = Lists.newArrayList();
int batchCount = batchGroups.size();
for (int i = 0; i < batchCount / 2; i++) {
if (batchGroups.size() == 0) {
break;
}
BatchGroup batch = batchGroups.pollLast();
assert batch != null : "Encountered a null batch during merge and spill operation";
batchGroupList.add(batch);
}
if (batchGroupList.size() == 0) {
return null;
}
int estimatedRecordSize = 0;
for (VectorWrapper<?> w : batchGroupList.get(0)) {
try {
estimatedRecordSize += TypeHelper.getSize(w.getField().getType());
} catch (UnsupportedOperationException e) {
estimatedRecordSize += 50;
}
}
int targetRecordCount = Math.max(1, COPIER_BATCH_MEM_LIMIT / estimatedRecordSize);
VectorContainer hyperBatch = constructHyperBatch(batchGroupList);
createCopier(hyperBatch, batchGroupList, outputContainer, true);
int count = copier.next(targetRecordCount);
assert count > 0;
logger.debug(
"mergeAndSpill: estimated record size = {}, target record count = {}",
estimatedRecordSize,
targetRecordCount);
// 1 output container is kept in memory, so we want to hold on to it and transferClone
// allows keeping ownership
VectorContainer c1 = VectorContainer.getTransferClone(outputContainer, oContext);
c1.buildSchema(BatchSchema.SelectionVectorMode.NONE);
c1.setRecordCount(count);
String spillDir = dirs.next();
Path currSpillPath = new Path(Joiner.on("/").join(spillDir, fileName));
currSpillDirs.add(currSpillPath);
String outputFile = Joiner.on("/").join(currSpillPath, spillCount++);
try {
fs.deleteOnExit(currSpillPath);
} catch (IOException e) {
// since this is meant to be used in a batches's spilling, we don't propagate the exception
logger.warn("Unable to mark spill directory " + currSpillPath + " for deleting on exit", e);
}
stats.setLongStat(Metric.SPILL_COUNT, spillCount);
BatchGroup newGroup = new BatchGroup(c1, fs, outputFile, oContext);
try (AutoCloseable a = AutoCloseables.all(batchGroupList)) {
logger.info("Merging and spilling to {}", outputFile);
while ((count = copier.next(targetRecordCount)) > 0) {
outputContainer.buildSchema(BatchSchema.SelectionVectorMode.NONE);
outputContainer.setRecordCount(count);
// note that addBatch also clears the outputContainer
newGroup.addBatch(outputContainer);
}
injector.injectChecked(
context.getExecutionControls(), INTERRUPTION_WHILE_SPILLING, IOException.class);
newGroup.closeOutputStream();
} catch (Throwable e) {
// we only need to cleanup newGroup if spill failed
try {
AutoCloseables.close(e, newGroup);
} catch (Throwable t) {
/* close() may hit the same IO issue; just ignore */
}
throw UserException.resourceError(e)
.message("External Sort encountered an error while spilling to disk")
.addContext(e.getMessage() /* more detail */)
.build(logger);
} finally {
hyperBatch.clear();
}
logger.debug("mergeAndSpill: final total size in memory = {}", oAllocator.getAllocatedMemory());
logger.info("Completed spilling to {}", outputFile);
return newGroup;
}