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https://issues.apache.org/jira/browse/APEXMALHAR-2066?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15323411#comment-15323411
]
ASF GitHub Bot commented on APEXMALHAR-2066:
--------------------------------------------
Github user bhupeshchawda commented on a diff in the pull request:
https://github.com/apache/apex-malhar/pull/282#discussion_r66526171
--- Diff:
library/src/main/java/com/datatorrent/lib/db/jdbc/AbstractJdbcPollInputOperator.java
---
@@ -0,0 +1,652 @@
+/**
+ * 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 com.datatorrent.lib.db.jdbc;
+
+import java.io.IOException;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.atomic.AtomicReference;
+
+import javax.validation.constraints.Min;
+
+import org.slf4j.LoggerFactory;
+
+import org.apache.apex.malhar.lib.wal.FSWindowDataManager;
+import org.apache.apex.malhar.lib.wal.WindowDataManager;
+import org.apache.commons.lang3.tuple.MutablePair;
+
+import com.datatorrent.api.Context;
+import com.datatorrent.api.Context.OperatorContext;
+import com.datatorrent.api.DefaultPartition;
+import com.datatorrent.api.Operator.ActivationListener;
+import com.datatorrent.api.Operator.IdleTimeHandler;
+import com.datatorrent.api.Partitioner;
+import com.datatorrent.api.annotation.Stateless;
+import com.datatorrent.lib.db.AbstractStoreInputOperator;
+import com.datatorrent.lib.util.KeyValPair;
+import com.datatorrent.lib.util.KryoCloneUtils;
+import com.datatorrent.netlet.util.DTThrowable;
+
+/**
+ * Abstract operator for for consuming data using JDBC interface<br>
+ * User needs User needs to provide
+ * tableName,dbConnection,setEmitColumnList,look-up key <br>
+ * Optionally batchSize,pollInterval,Look-up key and a where clause can be
given
+ * <br>
+ * This operator uses static partitioning to arrive at range queries for
exactly
+ * once reads<br>
+ * Assumption is that there is an ordered column using which range queries
can
+ * be formed<br>
+ * If an emitColumnList is provided, please ensure that the keyColumn is
the
+ * first column in the list<br>
+ * Range queries are formed using the {@link JdbcMetaDataUtility}} Output -
+ * comma separated list of the emit columns eg columnA,columnB,columnC
+ *
+ * @displayName Jdbc Polling Input Operator
+ * @category Input
+ * @tags database, sql, jdbc, partitionable,exactlyOnce
+ */
+public abstract class AbstractJdbcPollInputOperator<T> extends
AbstractStoreInputOperator<T, JdbcStore>
+ implements ActivationListener<Context>, IdleTimeHandler,
Partitioner<AbstractJdbcPollInputOperator<T>>
+{
+ /*
+ * poll interval in milliseconds
+ */
+ private int pollInterval;
+
+ @Min(1)
+ private int partitionCount = 1;
+ protected transient int operatorId;
+ protected transient boolean isReplayed;
+ protected transient boolean isPollable;
+ protected int batchSize;
+ protected int fetchSize;
+ /**
+ * Map of windowId to <lower bound,upper bound> of the range key
+ */
+ protected transient MutablePair<String, String>
currentWindowRecoveryState;
+
+ /**
+ * size of the emit queue used to hold polled records before emit
+ */
+ private int queueCapacity = 4 * 1024 * 1024;
+ private transient volatile boolean execute;
+ private transient AtomicReference<Throwable> cause;
+ protected transient int spinMillis;
+ private transient OperatorContext context;
+ protected String tableName;
+ protected String key;
+ protected long currentWindowId;
+ protected KeyValPair<String, String> rangeQueryPair;
+ protected String lower;
+ protected String upper;
+ protected boolean recovered;
+ protected boolean isPolled;
+ protected String whereCondition = null;
+ protected String previousUpperBound;
+ protected String highestPolled;
+ private static final String user = "user";
+ private static final String password = "password";
+ /**
+ * thread to poll database
+ */
+ private transient Thread dbPoller;
+ protected transient ArrayBlockingQueue<List<T>> emitQueue;
+ protected transient PreparedStatement ps;
+ protected WindowDataManager windowManager;
+ private String emitColumnList;
+
+ /**
+ * Returns the where clause
+ */
+ public String getWhereCondition()
+ {
+ return whereCondition;
+ }
+
+ /**
+ * Sets the where clause
+ */
+ public void setWhereCondition(String whereCondition)
+ {
+ this.whereCondition = whereCondition;
+ }
+
+ /**
+ * Returns the list of columns to select from the query
+ */
+ public String getEmitColumnList()
+ {
+ return emitColumnList;
+ }
+
+ /**
+ * Comma separated list of columns to select from the given table
+ */
+ public void setEmitColumnList(String emitColumnList)
+ {
+ this.emitColumnList = emitColumnList;
+ }
+
+ /**
+ * Returns the fetchsize for getting the results
+ */
+ public int getFetchSize()
+ {
+ return fetchSize;
+ }
+
+ /**
+ * Sets the fetchsize for getting the results
+ */
+ public void setFetchSize(int fetchSize)
+ {
+ this.fetchSize = fetchSize;
+ }
+
+ protected abstract void pollRecords(PreparedStatement ps);
+
+ /**
+ * Returns the interval for polling the queue
+ */
+ public int getPollInterval()
+ {
+ return pollInterval;
+ }
+
+ /**
+ * Sets the interval for polling the emit queue
+ */
+ public void setPollInterval(int pollInterval)
+ {
+ this.pollInterval = pollInterval;
+ }
+
+ /**
+ * Returns the capacity of the emit queue
+ */
+ public int getQueueCapacity()
+ {
+ return queueCapacity;
+ }
+
+ /**
+ * Sets the capacity of the emit queue
+ */
+ public void setQueueCapacity(int queueCapacity)
+ {
+ this.queueCapacity = queueCapacity;
+ }
+
+ /**
+ * Returns the ordered key used to generate the range queries
+ */
+ public String getKey()
+ {
+ return key;
+ }
+
+ /**
+ * Sets the ordered key used to generate the range queries
+ */
+ public void setKey(String key)
+ {
+ this.key = key;
+ }
+
+ /**
+ * Returns the tableName which would be queried
+ */
+ public String getTableName()
+ {
+ return tableName;
+ }
+
+ /**
+ * Sets the tableName to query
+ */
+ public void setTableName(String tableName)
+ {
+ this.tableName = tableName;
+ }
+
+ /**
+ * Returns rangeQueryPair - <lowerBound,upperBound>
+ */
+ public KeyValPair<String, String> getRangeQueryPair()
+ {
+ return rangeQueryPair;
+ }
+
+ /**
+ * Sets the rangeQueryPair <lowerBound,upperBound>
+ */
+ public void setRangeQueryPair(KeyValPair<String, String> rangeQueryPair)
+ {
+ this.rangeQueryPair = rangeQueryPair;
+ }
+
+ /**
+ * Returns batchSize indicating the number of elements in emitQueue
+ */
+ public int getBatchSize()
+ {
+ return batchSize;
+ }
+
+ /**
+ * Sets batchSize for number of elements in the emitQueue
+ */
+ public void setBatchSize(int batchSize)
+ {
+ this.batchSize = batchSize;
+ }
+
+ public AbstractJdbcPollInputOperator()
+ {
+ this.pollInterval = 10 * 1000;
+ this.fetchSize = 10000;
+ currentWindowRecoveryState = new MutablePair<>();
+ windowManager = new FSWindowDataManager();
+ }
+
+ @Override
+ public void setup(OperatorContext context)
+ {
+ super.setup(context);
+ spinMillis = context.getValue(Context.OperatorContext.SPIN_MILLIS);
+ execute = true;
+ cause = new AtomicReference<Throwable>();
+ emitQueue = new ArrayBlockingQueue<List<T>>(queueCapacity);
+ this.context = context;
+ operatorId = context.getId();
+
+ try {
+
+ //If its a range query pass upper and lower bounds
+ //If its a polling query pass only the lower bound
+ if (getRangeQueryPair().getValue() != null) {
+ ps = store.getConnection()
+ .prepareStatement(
+ JdbcMetaDataUtility.buildRangeQuery(getTableName(),
getKey(), rangeQueryPair.getKey(),
+ rangeQueryPair.getValue()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ } else {
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildPollableQuery(getTableName(),
getKey(), rangeQueryPair.getKey()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ isPollable = true;
+ }
+
+ } catch (SQLException e) {
+ LOG.error("Exception in initializing the range query for a given
partition", e);
+ throw new RuntimeException();
+ }
+
+ windowManager.setup(context);
+ LOG.debug("super setup done...");
+ }
+
+ @Override
+ public void beginWindow(long windowId)
+ {
+ currentWindowId = windowId;
+
+ isReplayed = false;
+
+ if (currentWindowId <= windowManager.getLargestRecoveryWindow()) {
+ try {
+ replay(currentWindowId);
+ } catch (SQLException e) {
+ LOG.error("Exception in replayed windows", e);
+ throw new RuntimeException(e);
+ }
+ }
+
+ if (isReplayed && currentWindowId ==
windowManager.getLargestRecoveryWindow()) {
+ try {
+ if (!isPollable && rangeQueryPair.getValue() != null) {
+
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildGTRangeQuery(getTableName(),
getKey(), previousUpperBound,
+ rangeQueryPair.getValue()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ } else {
+ String bound = null;
+ if (previousUpperBound == null) {
+ bound = getRangeQueryPair().getKey();
+ } else {
+ bound = previousUpperBound;
+ }
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildPollableQuery(getTableName(),
getKey(), bound),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ isPollable = true;
+ }
+ isReplayed = false;
+ LOG.debug("Prepared statement after re-initialization - " +
ps.toString());
+ } catch (SQLException e) {
+ // TODO Auto-generated catch block
+ throw new RuntimeException(e);
+ }
+ }
+
+ //Reset the pollable query with the updated upper and lower bounds
+ if (isPollable) {
+ try {
+ String bound = null;
+ if (previousUpperBound == null && highestPolled == null) {
+ bound = getRangeQueryPair().getKey();
+ } else {
+ bound = highestPolled;
+ }
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildPollableQuery(getTableName(),
getKey(), bound),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ LOG.debug("Polling query " + ps.toString() + "," +
currentWindowId);
+ isPolled = false;
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ lower = null;
+ upper = null;
+
+ //Check if a thread is already active and start only if its no
+ //Do not start the thread from setup, will conflict with the replay
+ if (dbPoller == null && !isReplayed) {
+ //If this is not a replayed state, reset the ps to highest read
offset + 1,
+ //keep the upper bound as the one that was initialized after static
partitioning
+ LOG.info("Statement when re-initialized" + ps.toString());
+ dbPoller = new Thread(new DBPoller());
+ dbPoller.start();
+ }
+ }
+
+ @Override
+ public void emitTuples()
+ {
+ if (isReplayed) {
+ return;
+ }
+
+ List<T> tuples;
+
+ if ((tuples = emitQueue.poll()) != null) {
+ for (Object tuple : tuples) {
+ if (lower == null) {
+ lower = tuple.toString();
+ }
+ upper = tuple.toString();
+ outputPort.emit((T)tuple);
+ }
+ }
+ }
+
+ @Override
+ public void endWindow()
+ {
+ try {
+ if (currentWindowId > windowManager.getLargestRecoveryWindow()) {
+ if (currentWindowRecoveryState == null) {
+ currentWindowRecoveryState = new MutablePair<String, String>();
+ }
+ if (lower != null && upper != null) {
+ previousUpperBound = upper;
+ isPolled = true;
+ }
+ MutablePair<String, String> windowBoundaryPair = new
MutablePair<>(lower, upper);
+ currentWindowRecoveryState = windowBoundaryPair;
+ windowManager.save(currentWindowRecoveryState, operatorId,
currentWindowId);
+ }
+ } catch (IOException e) {
+ throw new RuntimeException("saving recovery", e);
+ }
+ currentWindowRecoveryState = new MutablePair<>();
+ }
+
+ public int getPartitionCount()
+ {
+ return partitionCount;
+ }
+
+ public void setPartitionCount(int partitionCount)
+ {
+ this.partitionCount = partitionCount;
+ }
+
+ @Override
+ public void activate(Context cntxt)
+ {
+ if (context.getValue(OperatorContext.ACTIVATION_WINDOW_ID) !=
Stateless.WINDOW_ID
+ && context.getValue(OperatorContext.ACTIVATION_WINDOW_ID) <
windowManager.getLargestRecoveryWindow()) {
+ // If it is a replay state, don't start any threads here
+ return;
+ }
+ }
+
+ @Override
+ public void deactivate()
+ {
+ try {
+ if (dbPoller != null && dbPoller.isAlive()) {
+ dbPoller.interrupt();
+ dbPoller.join();
+ }
+ } catch (InterruptedException ex) {
+ // log and ignore, ending execution anyway
+ LOG.error("exception in poller thread: ", ex);
+ }
+ }
+
+ @Override
+ public void handleIdleTime()
+ {
+ if (execute) {
+ try {
+ Thread.sleep(spinMillis);
+ } catch (InterruptedException ie) {
+ throw new RuntimeException(ie);
+ }
+ } else {
+ LOG.error("Exception: ", cause);
+ DTThrowable.rethrow(cause.get());
+ }
+ }
+
+ protected void replay(long windowId) throws SQLException
+ {
+ isReplayed = true;
+
+ MutablePair<String, String> recoveredData = new MutablePair<String,
String>();
+ try {
+ recoveredData = (MutablePair<String,
String>)windowManager.load(operatorId, windowId);
+
+ if (recoveredData != null) {
+ //skip the window and return if there was no incoming data in the
window
+ if (recoveredData.left == null || recoveredData.right == null) {
+ return;
+ }
+
+ if (recoveredData.right.equals(rangeQueryPair.getValue()) ||
recoveredData.right.equals(previousUpperBound)) {
+ LOG.info("Matched so returning");
+ return;
+ }
+
+ JdbcPollInputOperator jdbcPoller = new JdbcPollInputOperator();
+ jdbcPoller.setStore(store);
+ jdbcPoller.setKey(getKey());
+ jdbcPoller.setPartitionCount(getPartitionCount());
+ jdbcPoller.setPollInterval(50);
--- End diff --
Should this be a constant? If so, can you declare this as a _DEFAULT at the
top?
> Add jdbc poller input operator
> ------------------------------
>
> Key: APEXMALHAR-2066
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2066
> Project: Apache Apex Malhar
> Issue Type: Task
> Reporter: Ashwin Chandra Putta
> Assignee: devendra tagare
>
> Create a JDBC poller input operator that has the following features.
> 1. poll from external jdbc store asynchronously in the input operator.
> 2. polling frequency and batch size should be configurable.
> 3. should be idempotent.
> 4. should be partition-able.
> 5. should be batch + polling capable.
> Assumptions for idempotency & partitioning,
> 1.User needs to provide tableName,dbConnection,setEmitColumnList,look-up key.
> 2.Optionally batchSize,pollInterval,Look-up key and a where clause can be
> given.
> 3.This operator uses static partitioning to arrive at range queries for
> exactly once reads
> 4.Assumption is that there is an ordered column using which range queries can
> be formed<br>
> 5.If an emitColumnList is provided, please ensure that the keyColumn is the
> first column in the list
> 6.Range queries are formed using the JdbcMetaDataUtility Output - comma
> separated list of the emit columns eg columnA,columnB,columnC
> Per window the first and the last key processed is saved using the
> FSWindowDataManager - (<lowerBound,UpperBound>,operatorId,windowId).This
> (lowerBound,upperBoundPair) is then used for recovery.The queries are
> constructed using the JDBCMetaDataUtility.
> JDBCMetaDataUtility
> A utility class used to retrieve the metadata for a given unique key of a SQL
> table. This class would emit range queries based on a primary index given.
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