gianm commented on code in PR #16863:
URL: https://github.com/apache/druid/pull/16863#discussion_r1730233325
##########
processing/src/main/java/org/apache/druid/segment/data/CompressedBlockReader.java:
##########
@@ -169,16 +177,21 @@ public ByteBuffer getRange(long startOffset, int size)
if (size == 0) {
return NULL_VALUE;
}
-
final int startBlockOffset = loadBlock(startOffset);
final int startBlockNumber = currentBlockNumber;
decompressedDataBuffer.position(startBlockOffset);
- // patch together value from n underlying compressed pages
+ // possibly patch together value from n underlying compressed pages
if (size < decompressedDataBuffer.remaining()) {
- // sweet, same buffer, we can slice out a view directly to the value
- final ByteBuffer dupe =
decompressedDataBuffer.duplicate().order(byteOrder);
- dupe.position(startBlockOffset).limit(startBlockOffset + size);
- return dupe.slice().order(byteOrder);
+ // sweet, same buffer, we can return the buffer directly with position
and limit set
Review Comment:
this comment appears to no longer be 100% accurate
##########
processing/src/main/java/org/apache/druid/segment/serde/ComplexMetricSerde.java:
##########
@@ -142,14 +120,100 @@ public Object fromBytes(byte[] data, int start, int
numBytes)
}
/**
- * This method provides the ability for a ComplexMetricSerde to control its
own serialization.
- * For large column (i.e columns greater than {@link Integer#MAX_VALUE}) use
- * {@link LargeColumnSupportedComplexColumnSerializer}
+ * Deserializes a ByteBuffer and adds it to the ColumnBuilder. This method
allows for the ComplexMetricSerde
+ * to implement it's own versioning scheme to allow for changes of binary
format in a forward-compatible manner.
*
- * @return an instance of GenericColumnSerializer used for serialization.
+ * @param buffer the buffer to deserialize
+ * @param builder ColumnBuilder to add the column to
+ * @param columnConfig ColumnConfiguration used during deserialization
+ */
+ public void deserializeColumn(
+ ByteBuffer buffer,
+ ColumnBuilder builder,
+ ColumnConfig columnConfig
+ )
+ {
+ deserializeColumn(buffer, builder);
+ }
+
+
+ /**
+ * {@link ComplexMetricSerde#deserializeColumn(ByteBuffer, ColumnBuilder,
ColumnConfig)} should be used instead of this.
+ * This method is left for backward compatibility.
*/
+ @Deprecated
+ public void deserializeColumn(ByteBuffer buffer, ColumnBuilder builder)
+ {
+ // default implementation to match default serializer implementation
+ final int position = buffer.position();
+ final byte version = buffer.get();
+ if (version == CompressedComplexColumnSerializer.IS_COMPRESSED) {
+ CompressedComplexColumnSupplier supplier =
CompressedComplexColumnSupplier.read(
+ buffer,
+ builder,
+ getTypeName(),
+ getObjectStrategy()
+ );
+ builder.setComplexColumnSupplier(supplier);
+ builder.setNullValueIndexSupplier(supplier.getNullValues());
+ builder.setHasNulls(!supplier.getNullValues().isEmpty());
+ } else {
+ buffer.position(position);
+ builder.setComplexColumnSupplier(
+ new ComplexColumnPartSupplier(
+ getTypeName(),
+ GenericIndexed.read(buffer, getObjectStrategy(),
builder.getFileMapper())
+ )
+ );
+ }
+ }
+
+ /**
+ * {@link ComplexMetricSerde#getSerializer(SegmentWriteOutMedium, String,
IndexSpec)} should be used instead of this.
+ * This method is left for backward compatibility.
+ */
+ @Nullable
+ @Deprecated
public GenericColumnSerializer getSerializer(SegmentWriteOutMedium
segmentWriteOutMedium, String column)
{
- return ComplexColumnSerializer.create(segmentWriteOutMedium, column,
this.getObjectStrategy());
+ return null;
+ }
+
+ /**
+ * This method provides the ability for a ComplexMetricSerde to control its
own serialization.
+ * Default implementation uses {@link CompressedComplexColumnSerializer} if
{@link IndexSpec#complexMetricCompression}
+ * is not null or uncompressed/none, or {@link
LargeColumnSupportedComplexColumnSerializer} if no compression is
+ * specified.
+ *
+ * @return an instance of {@link GenericColumnSerializer} used for
serialization.
+ */
+ public GenericColumnSerializer getSerializer(
+ SegmentWriteOutMedium segmentWriteOutMedium,
+ String column,
+ IndexSpec indexSpec
+ )
+ {
+ // backwards compatibility, if defined use it
+ final GenericColumnSerializer serializer =
getSerializer(segmentWriteOutMedium, column);
+ if (serializer != null) {
+ return serializer;
+ }
+
+ // otherwise, use compressed or generic indexed based serializer
+ CompressionStrategy strategy = indexSpec.getComplexMetricCompression();
+ if (strategy == null || CompressionStrategy.NONE == strategy ||
CompressionStrategy.UNCOMPRESSED == strategy) {
+ return LargeColumnSupportedComplexColumnSerializer.create(
Review Comment:
The old code had a default of `ComplexColumnSerializer`. Why change that?
(Is it strictly better? Are there compatibility concerns?)
##########
processing/src/main/java/org/apache/druid/segment/data/ObjectStrategy.java:
##########
@@ -59,6 +60,19 @@ default boolean canCompare()
return true;
}
+ /**
+ * Whether the {@link #fromByteBuffer(ByteBuffer, int)}, {@link
#fromByteBufferWithSize(ByteBuffer)}, and
+ * {@link #fromByteBufferSafe(ByteBuffer, int)} methods return an object
that may retain a reference to the provided
+ * {@link ByteBuffer}. If a reference is sometimes retained, this method
returns true. It returns false if, and only
Review Comment:
Should clarify: does this mean "retains a reference to the specific
ByteBuffer object" or "retains a reference to the same underlying memory"?
i.e., if an ObjectStrategy calls `duplicate()` on the buf and retains the
duplicate, should it return `true` or `false` from this method?
##########
processing/src/main/java/org/apache/druid/segment/serde/CompressedComplexColumnSerializer.java:
##########
@@ -0,0 +1,164 @@
+/*
+ * 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.druid.segment.serde;
+
+import com.google.common.base.Preconditions;
+import org.apache.druid.collections.bitmap.ImmutableBitmap;
+import org.apache.druid.collections.bitmap.MutableBitmap;
+import org.apache.druid.java.util.common.io.smoosh.FileSmoosher;
+import org.apache.druid.segment.ColumnValueSelector;
+import org.apache.druid.segment.GenericColumnSerializer;
+import org.apache.druid.segment.IndexMerger;
+import org.apache.druid.segment.IndexSpec;
+import org.apache.druid.segment.data.ByteBufferWriter;
+import
org.apache.druid.segment.data.CompressedVariableSizedBlobColumnSerializer;
+import org.apache.druid.segment.data.ObjectStrategy;
+import org.apache.druid.segment.nested.NestedCommonFormatColumnSerializer;
+import org.apache.druid.segment.nested.NestedDataColumnMetadata;
+import org.apache.druid.segment.nested.NestedDataComplexTypeSerde;
+import org.apache.druid.segment.writeout.SegmentWriteOutMedium;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.channels.WritableByteChannel;
+
+public class CompressedComplexColumnSerializer<T> implements
GenericColumnSerializer<T>
+{
+ public static final byte IS_COMPRESSED = Byte.MAX_VALUE;
+ public static final byte V0 = 0x00;
+ public static final String FILE_NAME = "__complexColumn";
+
+ public static GenericColumnSerializer create(
+ SegmentWriteOutMedium segmentWriteOutMedium,
+ String column,
+ IndexSpec indexSpec,
+ ObjectStrategy objectStrategy
+ )
+ {
+ return new CompressedComplexColumnSerializer(column,
segmentWriteOutMedium, indexSpec, objectStrategy);
+ }
+
+ public CompressedComplexColumnSerializer(
+ String name,
+ SegmentWriteOutMedium segmentWriteOutMedium,
+ IndexSpec indexSpec,
+ ObjectStrategy<T> strategy
+ )
+ {
+ this.name = name;
+ this.segmentWriteOutMedium = segmentWriteOutMedium;
+ this.indexSpec = indexSpec;
+ this.strategy = strategy;
+ }
+
+ private final String name;
+ private final SegmentWriteOutMedium segmentWriteOutMedium;
+ private final IndexSpec indexSpec;
+ private final ObjectStrategy<T> strategy;
+ private CompressedVariableSizedBlobColumnSerializer writer;
+ private ByteBufferWriter<ImmutableBitmap> nullBitmapWriter;
+ private MutableBitmap nullRowsBitmap;
+
+ private int rowCount = 0;
+ private boolean closedForWrite = false;
+ private byte[] metadataBytes;
+
+ @Override
+ public void open() throws IOException
+ {
+ writer = new CompressedVariableSizedBlobColumnSerializer(
+ NestedCommonFormatColumnSerializer.getInternalFileName(name,
FILE_NAME),
+ segmentWriteOutMedium,
+ indexSpec.getComplexMetricCompression()
+ );
+ writer.open();
+
+ nullBitmapWriter = new ByteBufferWriter<>(
+ segmentWriteOutMedium,
+ indexSpec.getBitmapSerdeFactory().getObjectStrategy()
+ );
+ nullBitmapWriter.open();
+
+ nullRowsBitmap =
indexSpec.getBitmapSerdeFactory().getBitmapFactory().makeEmptyMutableBitmap();
+ }
+
+ @Override
+ public void serialize(ColumnValueSelector<? extends T> selector) throws
IOException
+ {
+ final T data = selector.getObject();
+ if (data == null) {
+ nullRowsBitmap.add(rowCount);
+ }
+ rowCount++;
+ final byte[] bytes = strategy.toBytes(data);
+ writer.addValue(bytes);
+ }
+
+ @Override
+ public long getSerializedSize() throws IOException
+ {
+ closeForWrite();
+ // COMPRESSED_BYTE + V0 + metadata
+ return 1 + 1 + metadataBytes.length;
+ }
+
+ @Override
+ public void writeTo(WritableByteChannel channel, FileSmoosher smoosher)
throws IOException
+ {
+ Preconditions.checkState(closedForWrite, "Not closed yet!");
+
+ channel.write(ByteBuffer.wrap(new byte[]{IS_COMPRESSED}));
+ channel.write(ByteBuffer.wrap(new byte[]{V0}));
+ channel.write(ByteBuffer.wrap(metadataBytes));
+
+ NestedCommonFormatColumnSerializer.writeInternal(smoosher, writer, name,
FILE_NAME);
Review Comment:
perhaps move that `writeInternal` to a more neutral helper class? It seems
odd for the complex column serializer to call into an internal method of nested
column serializer. I mean, it's fine, just a little odd.
##########
processing/src/main/java/org/apache/druid/segment/nested/NestedDataColumnSerializer.java:
##########
@@ -394,18 +392,6 @@ private void closeForWrite() throws IOException
{
if (!closedForWrite) {
closedForWrite = true;
- ByteArrayOutputStream baos = new ByteArrayOutputStream();
Review Comment:
was this dead code?
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