private void buildTable() throws SchemaChangeException, ClassTransformationException, IOException {
// Get all samples from distributed map
SortRecordBatchBuilder containerBuilder = new SortRecordBatchBuilder(context.getAllocator(), MAX_SORT_BYTES);
for (CachedVectorContainer w : mmap.get(mapKey)) {
containerBuilder.add(w.get());
}
VectorContainer allSamplesContainer = new VectorContainer();
containerBuilder.build(context, allSamplesContainer);
List<Ordering> orderDefs = Lists.newArrayList();
int i = 0;
for (Ordering od : popConfig.getOrderings()) {
SchemaPath sp = SchemaPath.getSimplePath("f" + i++);
orderDefs.add(new Ordering(od.getDirection(), new FieldReference(sp)));
}
// sort the data incoming samples.
SelectionVector4 newSv4 = containerBuilder.getSv4();
Sorter sorter = SortBatch.createNewSorter(context, orderDefs, allSamplesContainer);
sorter.setup(context, newSv4, allSamplesContainer);
sorter.sort(newSv4, allSamplesContainer);
// Copy every Nth record from the samples into a candidate partition table, where N = totalSampledRecords/partitions
// Attempt to push this to the distributed map. Only the first candidate to get pushed will be used.
VectorContainer candidatePartitionTable = new VectorContainer();
SampleCopier copier = null;
List<ValueVector> localAllocationVectors = Lists.newArrayList();
copier = getCopier(newSv4, allSamplesContainer, candidatePartitionTable, orderDefs, localAllocationVectors);
int allocationSize = 50;
while (true) {
for (ValueVector vv : localAllocationVectors) {
AllocationHelper.allocate(vv, samplingFactor * partitions, allocationSize);
}
int skipRecords = containerBuilder.getSv4().getTotalCount() / partitions;
if (copier.copyRecords(skipRecords, skipRecords, partitions - 1)) {
assert copier.getOutputRecords() == partitions - 1 : String.format("output records: %d partitions: %d", copier.getOutputRecords(), partitions);
for (VectorWrapper<?> vw : candidatePartitionTable) {
vw.getValueVector().getMutator().setValueCount(copier.getOutputRecords());
}
break;
} else {
candidatePartitionTable.zeroVectors();
allocationSize *= 2;
}
}
candidatePartitionTable.setRecordCount(copier.getOutputRecords());
WritableBatch batch = WritableBatch.getBatchNoHVWrap(candidatePartitionTable.getRecordCount(), candidatePartitionTable, false);
CachedVectorContainer wrap = new CachedVectorContainer(batch, context.getDrillbitContext().getAllocator());
tableMap.putIfAbsent(mapKey + "final", wrap, 1, TimeUnit.MINUTES);
candidatePartitionTable.clear();
allSamplesContainer.clear();
containerBuilder.clear();
wrap.clear();
}