Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/5441#discussion_r167949288
--- Diff:
flink-libraries/flink-sql-client/src/main/java/org/apache/flink/table/client/gateway/DynamicResult.java
---
@@ -0,0 +1,253 @@
+/*
+ * 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.flink.table.client.gateway;
+
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.table.sinks.TableSink;
+import org.apache.flink.types.Row;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A result of a dynamic table program.
+ */
+public class DynamicResult {
+
+ private final boolean isChangelog;
+ private final CollectTableSink collectTableSink;
+ private final Object resultLock = new Object();
+ private final ResultRetrievalThread retrievalThread;
+ private final JobMonitoringThread monitoringThread;
+ private Runnable program;
+ private SqlExecutionException executionException;
+
+ // for table materialization
+ private final List<Row> materializedTable;
+ private final Map<Row, List<Integer>> rowPositions; // positions of
rows in table for faster access
+ private final List<Row> snapshot;
+ private int pageSize;
+ private boolean isLastSnapshot;
+
+ // for changelog
+ private Tuple2<Boolean, Row> nextChangeRecord;
+
+ public DynamicResult(InetAddress targetAddress, int targetPort, boolean
isChangelog) {
+ this.isChangelog = isChangelog;
+
+ // create table sink
+ collectTableSink = new CollectTableSink(targetAddress,
targetPort);
+ retrievalThread = new ResultRetrievalThread();
+ monitoringThread = new JobMonitoringThread();
+
+ // prepare for table materialization
+ materializedTable = new ArrayList<>();
+ rowPositions = new HashMap<>();
+ snapshot = new ArrayList<>();
+ isLastSnapshot = false;
+ }
+
+ public boolean isChangelog() {
+ return isChangelog;
+ }
+
+ public void startRetrieval(Runnable program) {
+ // start listener thread
+ retrievalThread.start();
+
+ // start program
+ this.program = program;
+ monitoringThread.start();
+ }
+
+ public TypedResult<Tuple2<Boolean, Row>> retrieveRecord() {
+ synchronized (resultLock) {
+ // retrieval thread is alive return a record if
available
+ // but the program must not have failed
+ if (retrievalThread.isRunning && executionException ==
null) {
+ if (nextChangeRecord == null) {
+ return TypedResult.empty();
+ } else {
+ final Tuple2<Boolean, Row> change =
nextChangeRecord;
+ nextChangeRecord = null;
+ resultLock.notify();
+ return TypedResult.payload(change);
+ }
+ }
+ // retrieval thread is dead but there is still a record
to be delivered
+ else if (!retrievalThread.isRunning && nextChangeRecord
!= null) {
+ final Tuple2<Boolean, Row> change =
nextChangeRecord;
+ nextChangeRecord = null;
+ return TypedResult.payload(change);
+ }
+ // no results can be returned anymore
+ else {
+ return handleMissingResult();
+ }
+ }
+ }
+
+ public TypedResult<Integer> snapshot(int pageSize) {
+ synchronized (resultLock) {
+ // retrieval thread is dead and there are no results
anymore
+ // or program failed
+ if ((!retrievalThread.isRunning && isLastSnapshot) ||
executionException != null) {
+ return handleMissingResult();
+ }
+ // this snapshot is the last result that can be
delivered
+ else if (!retrievalThread.isRunning) {
+ isLastSnapshot = true;
+ }
+
+ this.pageSize = pageSize;
+ snapshot.clear();
+ snapshot.addAll(materializedTable);
+
+ // at least one page
+ final int pageCount = Math.max(1, (int)
Math.ceil(((double) snapshot.size() / pageSize)));
+ return TypedResult.payload(pageCount);
+ }
+ }
+
+ public List<Row> retrievePage(int page) {
+ final int pageCount = Math.max(1, (int) Math.ceil(((double)
snapshot.size()) / pageSize));
--- End diff --
pageCount could be remembered
---
