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szymon-miezalmichaelsembwever
szymon-miezal
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michaelsembwever
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STAR-1903: ConsistencyLevel.THREE means ALL_BUT_ONE (#943)
Add a system property (dse.consistency_level.three_means_all_but_one) that changes the behavior of ConsistencyLevel.THREE to mean ALL_BUT_ONE, i.e. that all replicas except for at most one in the cluster (across all DCs) must accept the write for it to be successful. (cherry picked from commit 9875081) (Rebase of commit 8345fe9)
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‎src/java/org/apache/cassandra/config/CassandraRelevantProperties.java‎

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@@ -674,6 +674,9 @@ public enum CassandraRelevantProperties
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TEST_UTIL_ALLOW_TOOL_REINIT_FOR_TEST("org.apache.cassandra.tools.UtilALLOW_TOOL_REINIT_FOR_TEST"),
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/** Activate write survey mode. The node not becoming an active ring member, and you must use JMX StorageService->joinRing() to finalize the ring joining. */
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TEST_WRITE_SURVEY("cassandra.write_survey"),
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// Changes the semantic of the "THREE" consistency level to mean "all but one"
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// i.e. that all replicas except for at most one in the cluster (across all DCs) must accept the write for it to be successful.
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THREE_MEANS_ALL_BUT_ONE("dse.consistency_level.three_means_all_but_one", "false"),
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TOLERATE_SSTABLE_SIZE("cassandra.tolerate_sstable_size"),
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TRIGGERS_DIR("cassandra.triggers_dir"),
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TRUNCATE_BALLOT_METADATA("cassandra.truncate_ballot_metadata"),

‎src/java/org/apache/cassandra/db/ConsistencyLevel.java‎

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@@ -22,6 +22,7 @@
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import javax.annotation.Nullable;
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import com.carrotsearch.hppc.ObjectIntHashMap;
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import org.apache.cassandra.config.CassandraRelevantProperties;
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import org.apache.cassandra.locator.Endpoints;
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import org.apache.cassandra.locator.InOurDc;
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import org.apache.cassandra.schema.TableMetadata;
@@ -51,6 +52,8 @@ public enum ConsistencyLevel
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LOCAL_ONE (10, true),
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NODE_LOCAL (11, true);
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public static final boolean THREE_MEANS_ALL_BUT_ONE = CassandraRelevantProperties.THREE_MEANS_ALL_BUT_ONE.getBoolean();
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// Used by the binary protocol
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public final int code;
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private final boolean isDCLocal;
@@ -87,6 +90,16 @@ public static ConsistencyLevel fromCode(int code)
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return codeIdx[code];
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}
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@Override
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public String toString()
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{
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if (this == THREE && THREE_MEANS_ALL_BUT_ONE)
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{
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return "THREE (ALL_BUT_ONE)";
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}
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return super.toString();
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}
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public static ConsistencyLevel fromString(String str)
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{
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return valueOf(str.toUpperCase(Locale.US));
@@ -97,6 +110,12 @@ public static int quorumFor(AbstractReplicationStrategy replicationStrategy)
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return (replicationStrategy.getReplicationFactor().allReplicas / 2) + 1;
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}
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static int allButOneFor(AbstractReplicationStrategy replicationStrategy)
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{
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int rf = replicationStrategy.getReplicationFactor().fullReplicas;
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return rf <= 1 ? rf : rf - 1;
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}
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public static int localQuorumFor(AbstractReplicationStrategy replicationStrategy, String dc)
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{
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return (replicationStrategy instanceof NetworkTopologyStrategy)
@@ -146,6 +165,10 @@ public int blockFor(AbstractReplicationStrategy replicationStrategy)
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case TWO:
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return 2;
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case THREE:
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if (THREE_MEANS_ALL_BUT_ONE)
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{
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return allButOneFor(replicationStrategy);
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}
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return 3;
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case QUORUM:
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case SERIAL:

‎test/unit/org/apache/cassandra/db/ConsistencyLevelTest.java‎

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/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.cassandra.db;
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import java.net.UnknownHostException;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.Map;
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import com.google.common.collect.HashMultimap;
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import com.google.common.collect.Multimap;
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import org.junit.After;
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import org.junit.AfterClass;
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import org.junit.BeforeClass;
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import org.junit.Test;
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import org.apache.cassandra.config.DatabaseDescriptor;
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import org.apache.cassandra.dht.OrderPreservingPartitioner;
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import org.apache.cassandra.dht.Token;
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import org.apache.cassandra.locator.AbstractNetworkTopologySnitch;
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import org.apache.cassandra.locator.AbstractReplicationStrategy;
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import org.apache.cassandra.locator.EverywhereStrategy;
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import org.apache.cassandra.locator.IEndpointSnitch;
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import org.apache.cassandra.locator.InetAddressAndPort;
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import org.apache.cassandra.locator.LocalStrategy;
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import org.apache.cassandra.locator.NetworkTopologyStrategy;
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import org.apache.cassandra.locator.SimpleStrategy;
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import org.apache.cassandra.locator.TokenMetadata;
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import org.apache.cassandra.utils.Pair;
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import static org.junit.Assert.*;
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public class ConsistencyLevelTest
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{
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private static final String KS = "test";
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private static final Map<String, String> RACK = new HashMap<>(), DATACENTER = new HashMap<>();
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private static final IEndpointSnitch SNITCH = new AbstractNetworkTopologySnitch()
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{
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@Override
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public String getRack(InetAddressAndPort endpoint)
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{
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return RACK.getOrDefault(endpoint.getHostAddress(false), "RC1");
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}
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@Override
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public String getDatacenter(InetAddressAndPort endpoint)
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{
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return DATACENTER.getOrDefault(endpoint.getHostAddress(false), "DC1");
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}
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};
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@BeforeClass
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public static void setSnitch()
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{
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DatabaseDescriptor.daemonInitialization();
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DatabaseDescriptor.setEndpointSnitch(SNITCH);
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}
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@AfterClass
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public static void resetSnitch()
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{
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DatabaseDescriptor.setEndpointSnitch(null);
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}
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@After
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public void resetSnitchState()
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{
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RACK.clear();
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DATACENTER.clear();
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}
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@Test
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public void allButOne_shouldBe_2_forReplicationFactor_3()
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{
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testAllButOne(simpleStrategy(3), 2);
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}
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@Test
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public void allButOne_shouldBe_1_forReplicationFactor_2()
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{
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testAllButOne(simpleStrategy(2), 1);
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}
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@Test
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public void allButOne_shouldBe_1_forReplicationFactor_1()
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{
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testAllButOne(simpleStrategy(1), 1);
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}
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@Test
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public void allButOne_shouldBe_1_forLocalStrategy()
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{
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testAllButOne(localStrategy(), 1);
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}
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@Test
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public void allButOne_shouldBe_8_forReplicationFactor_3_3_3()
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{
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testAllButOne(networkTopologyStrategy(3, 3, 3), 8);
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}
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@Test
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public void allButOne_shouldBe_11_forEverywhereStrategyOnClusterOf_12() throws Exception
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{
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testAllButOne(everywhereStrategy(
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dc(1, Pair.create("192.168.0.1", "A"), Pair.create("192.168.0.2", "E"), Pair.create("192.168.0.3", "H"),
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Pair.create("192.168.0.4", "C"), Pair.create("192.168.0.5", "I"), Pair.create("192.168.0.6", "J")),
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dc(2, Pair.create("192.168.1.1", "B"), Pair.create("192.168.1.2", "G"), Pair.create("192.168.1.3", "L"),
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Pair.create("192.168.1.4", "D"), Pair.create("192.168.1.5", "F"), Pair.create("192.168.1.6", "K"))),
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11);
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}
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private void testAllButOne(AbstractReplicationStrategy replicationStrategy, int expected)
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{
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// when
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int blockFor = ConsistencyLevel.allButOneFor(replicationStrategy);
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// then
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assertEquals("number of nodes to block for", expected, blockFor);
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}
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private static NetworkTopologyStrategy networkTopologyStrategy(int... dc)
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{
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Map<String, String> config = new HashMap<>();
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for (int i = 0; i < dc.length; i++)
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{
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config.put("DC" + i, Integer.toString(dc[i]));
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}
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return new NetworkTopologyStrategy(KS, new TokenMetadata(), SNITCH, config);
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}
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private static AbstractReplicationStrategy simpleStrategy(int replicationFactory)
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{
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Map<String, String> config = Collections.singletonMap("replication_factor", Integer.toString(replicationFactory));
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return new SimpleStrategy(KS, new TokenMetadata(), SNITCH, config);
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}
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@SafeVarargs
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private static AbstractReplicationStrategy everywhereStrategy(Multimap<InetAddressAndPort, Token>... dcs)
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{
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TokenMetadata metadata = new TokenMetadata();
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for (Multimap<InetAddressAndPort, Token> dc : dcs)
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{
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metadata.updateNormalTokens(dc);
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}
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return new EverywhereStrategy(KS, metadata, SNITCH, Collections.emptyMap());
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}
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private static AbstractReplicationStrategy localStrategy()
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{
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return new LocalStrategy(KS, new TokenMetadata(), SNITCH, Collections.emptyMap());
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}
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private static Multimap<InetAddressAndPort, Token> dc(int id, Pair<String, String>... addressToken) throws UnknownHostException
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{
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Multimap<InetAddressAndPort, Token> dc = HashMultimap.create();
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for (Pair<String, String> pair : addressToken)
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{
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DATACENTER.put(pair.left, "DC" + id);
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dc.put(InetAddressAndPort.getByName(pair.left), new OrderPreservingPartitioner.StringToken(pair.right));
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}
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return dc;
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}
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}

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