omalley commented on a change in pull request #637:
URL: https://github.com/apache/orc/pull/637#discussion_r572311006
##########
File path: java/core/src/java/org/apache/orc/OrcConf.java
##########
@@ -105,6 +105,9 @@
"(default 10000 rows) else dictionary check will happen before\n" +
"writing first stripe. In both cases, the decision to use\n" +
"dictionary or not will be retained thereafter."),
+ DICTIONARY_FACTORY_CLASS_KEY("orc.dictionary.class.key", null,
Review comment:
Let's make this a simple string with values of "hash" or "rbtree".
##########
File path: java/core/src/java/org/apache/orc/impl/Dictionary.java
##########
@@ -0,0 +1,99 @@
+/*
+ * 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.orc.impl;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.Text;
+
+
+/**
+ * Interface to define the dictionary used for encoding value in columns of
specific types like string, char, varchar, etc.
+ */
+public interface Dictionary {
+ int INITIAL_DICTIONARY_SIZE = 4096;
+
+ interface DictionaryFactory {
+ Dictionary createDict(Configuration conf);
+ }
+
+ /**
+ * Traverse the whole dictionary and apply the action.
+ */
+ void visit(Visitor visitor) throws IOException;
+
+ void clear();
+
+ /**
+ * Given the position index, return the original string before being encoded.
+ */
+ void getText(Text result, int originalPosition);
+
+ int add(String value);
Review comment:
We shouldn't need the add(String).
##########
File path: java/core/src/java/org/apache/orc/impl/Dictionary.java
##########
@@ -0,0 +1,99 @@
+/*
+ * 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.orc.impl;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.Text;
+
+
+/**
+ * Interface to define the dictionary used for encoding value in columns of
specific types like string, char, varchar, etc.
+ */
+public interface Dictionary {
+ int INITIAL_DICTIONARY_SIZE = 4096;
+
+ interface DictionaryFactory {
Review comment:
I don't think I'd bother defining a factory interface.
##########
File path:
java/core/src/java/org/apache/orc/impl/writer/StringBaseTreeWriter.java
##########
@@ -64,6 +64,15 @@
WriterEncryptionVariant encryption,
WriterContext writer) throws IOException {
super(schema, encryption, writer);
+ Configuration conf = writer.getConfiguration();
+
Review comment:
I'd make a function that looks at the configuration value and builds the
hash or red-black dictionary directly. I can't see a need to make the
dictionary mechanism pluggable.
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