Ferix9288 commented on issue #11727:
URL: https://github.com/apache/pinot/issues/11727#issuecomment-1753657572
@jackjlli @Jackie-Jiang
Was able to replicate this via a unit test below:
```
/**
* 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.pinot.controller.helix.core.assignment.instance;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.commons.text.StringSubstitutor;
import org.apache.helix.model.InstanceConfig;
import org.apache.helix.zookeeper.datamodel.ZNRecord;
import org.apache.pinot.common.assignment.InstancePartitions;
import
org.apache.pinot.spi.config.table.assignment.InstanceReplicaGroupPartitionConfig;
import org.testng.annotations.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class InstanceReplicaGroupPartitionSelectorTest {
private static final String instanceConfigTemplate =
"{\n" +
" \"id\":
\"Server_pinot-server-${serverName}.pinot-server-headless.pinot.svc.cluster.local_8098\",\n"
+
" \"simpleFields\": {\n" +
" \"HELIX_ENABLED\": \"true\",\n" +
" \"HELIX_ENABLED_TIMESTAMP\": \"1688959934305\",\n" +
" \"HELIX_HOST\":
\"pinot-server-${serverName}.pinot-server-headless.pinot.svc.cluster.local\",\n"
+
" \"HELIX_PORT\": \"8098\",\n" +
" \"adminPort\": \"8097\",\n" +
" \"grpcPort\": \"8090\",\n" +
" \"queryMailboxPort\": \"46347\",\n" +
" \"queryServerPort\": \"45031\",\n" +
" \"shutdownInProgress\": \"false\"\n" +
" },\n" +
" \"mapFields\": {\n" +
" \"SYSTEM_RESOURCE_INFO\": {\n" +
" \"numCores\": \"16\",\n" +
" \"totalMemoryMB\": \"126976\",\n" +
" \"maxHeapSizeMB\": \"65536\"\n" +
" },\n" +
" \"pool\": {\n" +
" \"DefaultTenant_OFFLINE\": \"${pool}\",\n" +
" \"${poolName}\": \"${pool}\",\n" +
" \"AllReplicationGroups\": \"1\"\n" +
" }\n" +
" },\n" +
" \"listFields\": {\n" +
" \"TAG_LIST\": [\n" +
" \"DefaultTenant_OFFLINE\",\n" +
" \"DefaultTenant_REALTIME\",\n" +
" \"${poolName}\",\n" +
" \"AllReplicationGroups\"\n" +
" ]\n" +
" }\n" +
"}";
@Test
public void testSelectInstances() throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
String existingPartitionsJson =
" {\n" +
" \"instancePartitionsName\":
\"0f97dac8-4123-47c6-9a4d-b8ce039c5ea5_OFFLINE\",\n" +
" \"partitionToInstancesMap\": {\n" +
" \"0_0\": [\n" +
"
\"Server_pinot-server-rg0-0.pinot-server-headless.pinot.svc.cluster.local_8098\",\n"
+
"
\"Server_pinot-server-rg0-1.pinot-server-headless.pinot.svc.cluster.local_8098\"\n"
+
" ]\n" +
" }\n" +
" }\n";
InstancePartitions existing =
objectMapper.readValue(existingPartitionsJson, InstancePartitions.class);
InstanceReplicaGroupPartitionConfig config = new
InstanceReplicaGroupPartitionConfig(
true, 0, 2, 2, 1, 2, true, null
);
InstanceReplicaGroupPartitionSelector selector = new
InstanceReplicaGroupPartitionSelector(
config,
"tableNameBlah",
existing
);
String[] serverNames = {"rg0-0", "rg0-1", "rg1-0", "rg1-1"};
String[] poolNumbers = {"0", "0", "1", "1"};
String[] poolNames = {"FirstHalfReplicationGroups",
"FirstHalfReplicationGroups", "SecondHalfReplicationGroups",
"SecondHalfReplicationGroups"};
Map<Integer, List<InstanceConfig>> poolToInstanceConfigsMap = new
HashMap<>();
for (int i = 0; i < serverNames.length; i++) {
Map<String, String> valuesMap = new HashMap<>();
valuesMap.put("serverName", serverNames[i]);
valuesMap.put("pool", poolNumbers[i]);
valuesMap.put("poolName", poolNames[i]);
StringSubstitutor substitutor = new StringSubstitutor(valuesMap);
String resolvedString =
substitutor.replace(instanceConfigTemplate);
ZNRecord znRecord = objectMapper.readValue(resolvedString,
ZNRecord.class);
int poolNumber = Integer.parseInt(poolNumbers[i]);
poolToInstanceConfigsMap.computeIfAbsent(poolNumber, k -> new
ArrayList<>()).add(new InstanceConfig(znRecord));
}
InstancePartitions assignedPartitions = new
InstancePartitions("0f97dac8-4123-47c6-9a4d-b8ce039c5ea5_OFFLINE");
selector.selectInstances(poolToInstanceConfigsMap,
assignedPartitions);
String expectedInstancePartitions =
" {\n" +
" \"instancePartitionsName\":
\"0f97dac8-4123-47c6-9a4d-b8ce039c5ea5_OFFLINE\",\n" +
" \"partitionToInstancesMap\": {\n" +
" \"0_0\": [\n" +
"
\"Server_pinot-server-rg0-0.pinot-server-headless.pinot.svc.cluster.local_8098\",\n"
+
"
\"Server_pinot-server-rg0-1.pinot-server-headless.pinot.svc.cluster.local_8098\"\n"
+
" ],\n" +
" \"0_1\": [\n" +
"
\"Server_pinot-server-rg1-0.pinot-server-headless.pinot.svc.cluster.local_8098\",\n"
+
"
\"Server_pinot-server-rg1-1.pinot-server-headless.pinot.svc.cluster.local_8098\"\n"
+
" ]\n" +
" }\n" +
" }\n";
InstancePartitions expectedPartitions = objectMapper.readValue(
expectedInstancePartitions,
InstancePartitions.class
);
assert assignedPartitions.equals(expectedPartitions);
}
}
```
From my findings, can confirm that the current code just implodes when the
number of pools increase. Specifically:
```
for (int replicaGroupId = 0; replicaGroupId <
numCommonReplicaGroups; replicaGroupId++) {
Integer pool = replicaGroupIdToPoolMap.get(replicaGroupId);
if (pool == null) {
// Skip the replica group if it's no longer needed.
continue;
}
Set<String> candidateInstances =
poolToCandidateInstancesMap.computeIfAbsent(pool, k -> new
LinkedHashSet<>());
List<InstanceConfig> instanceConfigsInPool =
poolToInstanceConfigsMap.get(pool);
instanceConfigsInPool.forEach(k ->
candidateInstances.add(k.getInstanceName()));
for (int partitionId = 0; partitionId < existingNumPartitions;
partitionId++) {
List<String> existingInstances =
_existingInstancePartitions.getInstances(partitionId, replicaGroupId);
replicaGroupIdToExistingInstancesMap.computeIfAbsent(replicaGroupId, k -> new
HashSet<>())
.addAll(existingInstances);
}
}
```
The above code will only populate 1 of the two pools in
poolToCandidateInstancesMap which in turn causes the NPE below:
```
// If the new number of replica groups is greater than the existing
number of replica groups.
for (int replicaGroupId = existingNumReplicaGroups; replicaGroupId <
numReplicaGroups; replicaGroupId++) {
int pool = replicaGroupIdToPoolMap.get(replicaGroupId);
LinkedHashSet<String> candidateInstances = new
LinkedHashSet<>(poolToCandidateInstancesMap.get(pool));
```
I made a temp fix here (purely to show diff, not actually gonna merge)
https://github.com/apache/pinot/pull/11765
It's a temp fix because it doesn't exactly `minimizeDataMovement` because
everything gets screwed with the below:
```
for (int replicaId = 0; replicaId < numReplicaGroups; replicaId++) {
// Pick one pool for each replica-group based on the table name hash
int pool = pools.get((tableNameHash + replicaId) % numPools);
poolToReplicaGroupIdsMap.computeIfAbsent(pool, k -> new
ArrayList<>()).add(replicaId);
replicaGroupIdToPoolMap.put(replicaId, pool);
}
```
i.e. if replicaGroupId is not mapped to the same pool, the partition
selection gets jostled up (replicaGroupId 0 -> mapped to pool 1 is now instead
mapped to pool 2)
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org
For additional commands, e-mail: commits-h...@pinot.apache.org
