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https://issues.apache.org/jira/browse/PHOENIX-538?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14512270#comment-14512270
]
ASF GitHub Bot commented on PHOENIX-538:
----------------------------------------
Github user samarthjain commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/77#discussion_r29098156
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/expression/function/UDFExpression.java
---
@@ -0,0 +1,217 @@
+/*
+ * 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.expression.function;
+
+import static org.apache.phoenix.query.QueryServices.DYNAMIC_JARS_DIR_KEY;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.locks.Lock;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.hadoop.hbase.util.DynamicClassLoader;
+import org.apache.hadoop.hbase.util.KeyLocker;
+import org.apache.hadoop.io.WritableUtils;
+import org.apache.phoenix.compile.KeyPart;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.expression.visitor.ExpressionVisitor;
+import org.apache.phoenix.parse.PFunction;
+import org.apache.phoenix.schema.PName;
+import org.apache.phoenix.schema.PNameFactory;
+import org.apache.phoenix.schema.tuple.Tuple;
+import org.apache.phoenix.schema.types.PDataType;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.MapMaker;
+
+public class UDFExpression extends ScalarFunction {
+
+ private static Configuration config = HBaseConfiguration.create();
+
+ private static final ConcurrentMap<PName, DynamicClassLoader>
tenantIdSpecificCls =
+ new MapMaker().concurrencyLevel(3).weakValues().makeMap();
+
+ private static final ConcurrentMap<String, DynamicClassLoader>
pathSpecificCls =
+ new MapMaker().concurrencyLevel(3).weakValues().makeMap();
+
+ public static final Log LOG = LogFactory.getLog(UDFExpression.class);
+
+ /**
+ * A locker used to synchronize class loader initialization per tenant
id.
+ */
+ private static final KeyLocker<String> locker = new
KeyLocker<String>();
+
+ /**
+ * A locker used to synchronize class loader initialization per jar
path.
+ */
+ private static final KeyLocker<String> pathLocker = new
KeyLocker<String>();
+
+ private PName tenantId;
+ private String functionClassName;
+ private String jarPath;
+ private ScalarFunction udfFunction;
+
+ public UDFExpression() {
+ }
+
+ public UDFExpression(List<Expression> children,PFunction functionInfo)
{
+ super(children);
+ this.tenantId =
+ functionInfo.getTenantId() == null ? PName.EMPTY_NAME :
functionInfo.getTenantId();
+ this.functionClassName = functionInfo.getClassName();
+ this.jarPath = functionInfo.getJarPath();
+ constructUDFFunction();
+ }
+
+ @Override
+ public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
+ return udfFunction.evaluate(tuple, ptr);
+ }
+
+ @Override
+ public <T> T accept(ExpressionVisitor<T> visitor) {
+ return udfFunction.accept(visitor);
+ }
+
+ @Override
+ public PDataType getDataType() {
+ return udfFunction.getDataType();
+ }
+
+ @Override
+ public String getName() {
+ return udfFunction.getName();
+ }
+
+ @Override
+ public OrderPreserving preservesOrder() {
+ return udfFunction.preservesOrder();
+ }
+
+ @Override
+ public KeyPart newKeyPart(KeyPart childPart) {
+ return udfFunction.newKeyPart(childPart);
+ }
+
+ @Override
+ public int getKeyFormationTraversalIndex() {
+ return udfFunction.getKeyFormationTraversalIndex();
+ }
+
+ @Override
+ public void write(DataOutput output) throws IOException {
+ super.write(output);
+ WritableUtils.writeString(output, tenantId.getString());
+ WritableUtils.writeString(output, this.functionClassName);
+ if(this.jarPath == null) {
+ WritableUtils.writeString(output, "");
+ } else {
+ WritableUtils.writeString(output, this.jarPath);
+ }
+ }
+
+ @Override
+ public void readFields(DataInput input) throws IOException {
+ super.readFields(input);
+ this.tenantId =
PNameFactory.newName(WritableUtils.readString(input));
+ this.functionClassName = WritableUtils.readString(input);
+ String str = WritableUtils.readString(input);
+ this.jarPath = str.length() == 0 ? null: str;
+ constructUDFFunction();
+ }
+
+ private void constructUDFFunction() {
+ try {
+ DynamicClassLoader classLoader = getClassLoader(this.tenantId,
this.jarPath);
+ Class<?> clazz = classLoader.loadClass(this.functionClassName);
+ Constructor<?> constructor = clazz.getConstructor(List.class);
+ udfFunction =
(ScalarFunction)constructor.newInstance(this.children);
+ } catch (ClassNotFoundException | NoSuchMethodException |
SecurityException
+ | InstantiationException | IllegalAccessException |
IllegalArgumentException
+ | InvocationTargetException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public static DynamicClassLoader getClassLoader(final PName tenantId,
final String jarPath) {
+ DynamicClassLoader cl = tenantIdSpecificCls.get(tenantId);
+ String parent = null;
+ if (cl != null) return cl;
+ if(jarPath != null && !jarPath.isEmpty()) {
+ cl = pathSpecificCls.get(jarPath);
+ if (cl != null) return cl;
+ Path path = new Path(jarPath);
+ if(jarPath.endsWith(".jar")) {
+ parent = path.getParent().toString();
+ } else {
+ parent = path.toString();
+ }
+ }
+ if (jarPath == null || jarPath.isEmpty() ||
config.get(DYNAMIC_JARS_DIR_KEY) != null
+ && (parent != null &&
parent.equals(config.get(DYNAMIC_JARS_DIR_KEY)))) {
+ Lock lock = locker.acquireLock(tenantId.getString());
--- End diff --
Rajesh says: Just want to clarify one thing here the map is concurrent map
so get and putifAbsent will be atomic but there is a chance like between get
and put if other client already puts a class loader for the tenant then the
classloader and configuration object created become garbage. That's why using
locker. If that's ok I can do as you suggested. What do u say?
Samarth says: How expensive is creating a new classloader and config? To me
it doesn't look too expensive. So I wouldn't worry about creating and
discarding the two. Besides that race condition of another thread winning the
race between get() and putIfAbsent is not very likely. So to sum it up, yes, I
would get rid of the KeyLocker altogether.
> Support UDFs
> ------------
>
> Key: PHOENIX-538
> URL: https://issues.apache.org/jira/browse/PHOENIX-538
> Project: Phoenix
> Issue Type: Task
> Reporter: James Taylor
> Assignee: Rajeshbabu Chintaguntla
> Fix For: 5.0.0, 4.4.0
>
> Attachments: PHOENIX-538-wip.patch, PHOENIX-538_v1.patch,
> PHOENIX-538_v2.patch, PHOENIX-538_v3.patch, PHOENIX-538_v4.patch,
> PHOENIX-538_v5.patch, PHOENIX-538_v6.patch, PHOENIX-538_v6.patch
>
>
> Phoenix allows built-in functions to be added (as described
> [here](http://phoenix-hbase.blogspot.com/2013/04/how-to-add-your-own-built-in-function.html))
> with the restriction that they must be in the phoenix jar. We should improve
> on this and allow folks to declare new functions through a CREATE FUNCTION
> command like this:
> CREATE FUNCTION mdHash(anytype)
> RETURNS binary(16)
> LOCATION 'hdfs://path-to-my-jar' 'com.me.MDHashFunction'
> Since HBase supports loading jars dynamically, this would not be too
> difficult. The function implementation class would be required to extend our
> ScalarFunction base class. Here's how I could see it being implemented:
> * modify the phoenix grammar to support the new CREATE FUNCTION syntax
> * create a new UTFParseNode class to capture the parse state
> * add a new method to the MetaDataProtocol interface
> * add a new method in ConnectionQueryServices to invoke the MetaDataProtocol
> method
> * add a new method in MetaDataClient to invoke the ConnectionQueryServices
> method
> * persist functions in a new "SYSTEM.FUNCTION" table
> * add a new client-side representation to cache functions called PFunction
> * modify ColumnResolver to dynamically resolve a function in the same way we
> dynamically resolve and load a table
> * create and register a new ExpressionType called UDFExpression
> * at parse time, check for the function name in the built in list first (as
> is currently done), and if not found in the PFunction cache. If not found
> there, then use the new UDFExpression as a placeholder and have the
> ColumnResolver attempt to resolve it at compile time and throw an error if
> unsuccessful.
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