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https://issues.apache.org/jira/browse/ACCUMULO-626?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14997195#comment-14997195
]
ASF GitHub Bot commented on ACCUMULO-626:
-----------------------------------------
Github user keith-turner commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/50#discussion_r44318310
--- Diff:
iterator-test-harness/src/main/java/org/apache/accumulo/iteratortest/testcases/ReSeekTestCase.java
---
@@ -0,0 +1,107 @@
+/*
+ * 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.accumulo.iteratortest.testcases;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Random;
+import java.util.TreeMap;
+
+import org.apache.accumulo.core.data.ByteSequence;
+import org.apache.accumulo.core.data.Key;
+import org.apache.accumulo.core.data.Range;
+import org.apache.accumulo.core.data.Value;
+import org.apache.accumulo.core.iterators.SortedKeyValueIterator;
+import org.apache.accumulo.iteratortest.IteratorTestInput;
+import org.apache.accumulo.iteratortest.IteratorTestOutput;
+import org.apache.accumulo.iteratortest.IteratorTestUtil;
+import
org.apache.accumulo.iteratortest.environments.SimpleIteratorEnvironment;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Test case that verifies that an iterator can use the generated instance
from {@code deepCopy}.
+ */
+public class ReSeekTestCase extends OutputVerifyingTestCase {
+ private static final Logger log =
LoggerFactory.getLogger(ReSeekTestCase.class);
+
+ /**
+ * Let N be a random number between [0, RESEEK_INTERVAL). After every
Nth entry "returned" to the client, recreate and reseek the iterator.
+ */
+ private static final int RESEEK_INTERVAL = 4;
+
+ private final Random random;
+
+ public ReSeekTestCase() {
+ this.random = new Random();
+ }
+
+ @Override
+ public IteratorTestOutput test(IteratorTestInput testInput) {
+ final SortedKeyValueIterator<Key,Value> skvi =
IteratorTestUtil.instantiateIterator(testInput);
+ final SortedKeyValueIterator<Key,Value> source =
IteratorTestUtil.createSource(testInput);
+
+ try {
+ skvi.init(source, testInput.getIteratorOptions(), new
SimpleIteratorEnvironment());
+ skvi.seek(testInput.getRange(), Collections.<ByteSequence>
emptySet(), false);
+ return new IteratorTestOutput(consume(skvi, testInput));
+ } catch (IOException e) {
+ return new IteratorTestOutput(e);
+ }
+ }
+
+ TreeMap<Key,Value> consume(SortedKeyValueIterator<Key,Value> skvi,
IteratorTestInput testInput) throws IOException {
+ final TreeMap<Key,Value> data = new TreeMap<>();
+ final Range origRange = testInput.getRange();
+ int reseekCount = random.nextInt(RESEEK_INTERVAL);
+
+ int i = 0;
+ while (skvi.hasTop()) {
+ data.put(skvi.getTopKey(), skvi.getTopValue());
+
+ /*
+ * One of the trickiest cases in writing iterators:
+ *
+ * After any result is returned from a TabletServer to the client,
the Iterator in the TabletServer's memory may be torn down. To preserve the
state and
+ * guarantee that all records are received, the TabletServer does
remember the last Key it returned to the client. It will recreate the Iterator
(stack),
+ * and seek it using an updated Range. This range's start key is set
to the last Key returned, non-inclusive.
+ */
+ if (i % RESEEK_INTERVAL == reseekCount) {
+ // Last key
+ Key reSeekStartKey = skvi.getTopKey();
+
+ // Deepcopy the iterator
+ skvi = skvi.deepCopy(new SimpleIteratorEnvironment());
--- End diff --
creating a completely new iterator instance and initializing it would be
more realistic
> create an iterator fuzz tester
> ------------------------------
>
> Key: ACCUMULO-626
> URL: https://issues.apache.org/jira/browse/ACCUMULO-626
> Project: Accumulo
> Issue Type: New Feature
> Components: test
> Reporter: Eric Newton
> Assignee: Josh Elser
>
> Users often write iterators without fully understanding its limits and
> lifetime. Accumulo should have an iterator fuzz-tester which will take user
> data and run the iterator under extreme conditions. For example, it should
> re-create and re-seek the iterator with every key returned. It could
> automatically compare results of such a run with the naive run, which seeks
> to the beginning and scans all the data.
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