[GitHub] twdsilva commented on a change in pull request #428: PHOENIX-374: Enable access to dynamic columns in * or cf.* selection

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twdsilva commented on a change in pull request #428: PHOENIX-374: Enable access to dynamic columns in * or cf.* selection
URL: https://github.com/apache/phoenix/pull/428#discussion_r250337420
 
 

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 File path: phoenix-core/src/main/java/org/apache/phoenix/coprocessor/DynamicColumnWildcard.java
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+/*
+ * 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.phoenix.coprocessor;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Cell;
+import org.apache.hadoop.hbase.client.Mutation;
+import org.apache.hadoop.hbase.client.Put;
+import org.apache.hadoop.hbase.coprocessor.ObserverContext;
+import org.apache.hadoop.hbase.coprocessor.RegionCoprocessor;
+import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
+import org.apache.hadoop.hbase.coprocessor.RegionObserver;
+import org.apache.hadoop.hbase.regionserver.MiniBatchOperationInProgress;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.phoenix.coprocessor.generated.DynamicColumnMetaDataProtos;
+import org.apache.phoenix.coprocessor.generated.PTableProtos;
+import org.apache.phoenix.schema.PColumn;
+import org.apache.phoenix.schema.PColumnImpl;
+import org.apache.phoenix.util.ServerUtil;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.NavigableMap;
+import java.util.Optional;
+
+/**
+ * Coprocessor for exposing dynamic columns in wildcard queries. This coprocessor will be registered
+ * to physical HBase tables only i.e. PTableType.TABLE and is driven by the client-side config
+ * QueryServices.WILDCARD_QUERY_DYNAMIC_COLS_ATTRIB
+ * See PHOENIX-374
+ */
+public class DynamicColumnWildcard implements RegionObserver, RegionCoprocessor {
+
+    private static final Log LOG = LogFactory.getLog(DynamicColumnWildcard.class);
+    // Scan attribute that is set in case we want to project dynamic columns
+    public static final String WILDCARD_SCAN_INCLUDES_DYNAMIC_COLUMNS =
+            "_WildcardScanIncludesDynCols";
+    public static final byte[] DYN_COLS_METADATA_CELL_QUALIFIER = Bytes.toBytes("#Dyn_");
+
+    @Override
+    public Optional<RegionObserver> getRegionObserver() {
+        return Optional.of(this);
+    }
+
+    @Override
+    public void preBatchMutate(ObserverContext<RegionCoprocessorEnvironment> c,
+            MiniBatchOperationInProgress<Mutation> miniBatchOp) throws IOException {
+        try {
+            preBatchMutateWithExceptions(c, miniBatchOp);
+        } catch(Throwable t) {
+            // Wrap all exceptions in an IOException to prevent region server crashes
+            throw ServerUtil.createIOException("Unable to Put cells corresponding to dynamic" +
+                    "column metadata for " +
+                    c.getEnvironment().getRegion().getRegionInfo().getTable().getNameAsString(), t);
+        }
+    }
+
+    /**
+     * Iterate over all Put mutations and add metadata for the list of dynamic columns for each
+     * column family in its own cell under reserved qualifiers. This is used for resolving dynamic
+     * columns for wildcard queries. See PHOENIX-374
+     * @param c the region server environment
+     * @param miniBatchOp batch of mutations getting applied to region
+     * @throws IOException If an I/O error occurs when parsing protobuf
+     */
+    private void preBatchMutateWithExceptions(ObserverContext<RegionCoprocessorEnvironment> c,
+            MiniBatchOperationInProgress<Mutation> miniBatchOp) throws IOException {
+        for (int i = 0; i < miniBatchOp.size(); i++) {
+            Mutation m = miniBatchOp.getOperation(i);
+            List<Mutation> putDynColMetaData = new ArrayList<>(1);
+            boolean isThereAnExtraPut = false;
+            if (m instanceof Put) {
+                // There is at max 1 extra Put (for dynamic column shadow cells) per original Put
+                putDynColMetaData.add(new Put(m.getRow()));
+                NavigableMap<byte[], List<Cell>> famCellMap = m.getFamilyCellMap();
+                for (byte[] fam : famCellMap.keySet()) {
+                    byte[] serializedDynColsList = m.getAttribute(Bytes.toString(fam));
+                    if (serializedDynColsList == null) {
+                        // There are no dynamic columns for this column family
+                        continue;
+                    }
+                    List<PTableProtos.PColumn> dynColsInThisFam = DynamicColumnMetaDataProtos.
+                            DynamicColumnMetaData.parseFrom(serializedDynColsList)
+                            .getDynamicColumnsList();
+                    for (PTableProtos.PColumn dynColProto : dynColsInThisFam) {
+                        // Add a column for this dynamic column to the metadata Put operation
+                        ((Put)putDynColMetaData.get(0)).addColumn(fam,
 
 Review comment:
   nit: can you create a local variable for the put and then call ```miniBatchOp.addOperationsFromCP``` if its not null

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