Question

我正在尝试使用谓词查询Hazelcast地图。我的谓词代码在没有索引的情况下可以正常工作，但是为了获得更好的性能，我想将索引放在key的Hazelcast映射中。

地图结构：IMap<Event, Long>-Event是POJO类。

<map name="event.map">
  <in-memory-format>NATIVE</in-memory-format>
  <backup-count>2</backup-count>
  <async-backup-count>0</async-backup-count>
  <time-to-live-seconds>30</time-to-live-seconds>
  <max-idle-seconds>0</max-idle-seconds>
  <eviction-policy>LFU</eviction-policy>
  <max-size policy="FREE_NATIVE_MEMORY_PERCENTAGE">25</max-size>
  <cache-deserialized-values>INDEX-ONLY</cache-deserialized-values>
  <indexes>
    <index ordered="true">eventType</index>
</indexes>
</map>

使用上面的Map配置，我得到以下异常：

Jul 19, 2019 10:04:21 PM com.hazelcast.map.impl.operation.HDEntryOperation
SEVERE: [127.0.0.1]:5701 [dev] [3.11.2] java.lang.IllegalArgumentException: There is no suitable accessor for 'eventType' on class 'java.lang.Long'
com.hazelcast.query.QueryException: java.lang.IllegalArgumentException: There is no suitable accessor for 'eventType' on class 'java.lang.Long'
        at com.hazelcast.query.impl.getters.ReflectionHelper.createGetter(ReflectionHelper.java:175)
        at com.hazelcast.query.impl.getters.Extractors.instantiateGetter(Extractors.java:124)
        at com.hazelcast.query.impl.getters.Extractors.getGetter(Extractors.java:101)
        at com.hazelcast.query.impl.getters.Extractors.extract(Extractors.java:63)
        at com.hazelcast.query.impl.QueryableEntry.extractAttributeValueFromTargetObject(QueryableEntry.java:144)
        at com.hazelcast.query.impl.QueryableEntry.extractAttributeValue(QueryableEntry.java:82)
        at com.hazelcast.query.impl.QueryableEntry.getAttributeValue(QueryableEntry.java:48)
        at com.hazelcast.query.impl.QueryableEntry.getConverter(QueryableEntry.java:67)
        at com.hazelcast.query.impl.IndexImpl.saveEntryIndex(IndexImpl.java:79)
        at com.hazelcast.query.impl.Indexes.saveEntryIndex(Indexes.java:164)
        at com.hazelcast.map.impl.recordstore.AbstractRecordStore.saveIndex(AbstractRecordStore.java:165)
        at com.hazelcast.map.impl.recordstore.DefaultRecordStore.putInternal(DefaultRecordStore.java:709)
        at com.hazelcast.map.impl.recordstore.DefaultRecordStore.setWithUncountedAccess(DefaultRecordStore.java:987)
        at com.hazelcast.map.impl.operation.EntryOperator.onAddedOrUpdated(EntryOperator.java:288)
        at com.hazelcast.map.impl.operation.EntryOperator.doPostOperateOps(EntryOperator.java:219)
        at com.hazelcast.map.impl.operation.HDEntryOperation.runVanilla(HDEntryOperation.java:257)
        at com.hazelcast.map.impl.operation.HDEntryOperation.runInternal(HDEntryOperation.java:95)
        at com.hazelcast.map.impl.operation.HDMapOperation.run(HDMapOperation.java:88)
        at com.hazelcast.spi.Operation.call(Operation.java:170)
        at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.call(OperationRunnerImpl.java:208)
        at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:197)
        at com.hazelcast.spi.impl.operationexecutor.impl.OperationExecutorImpl.run(OperationExecutorImpl.java:407)
        at com.hazelcast.spi.impl.operationexecutor.impl.OperationExecutorImpl.runOrExecute(OperationExecutorImpl.java:434)
        at com.hazelcast.spi.impl.operationservice.impl.Invocation.doInvokeLocal(Invocation.java:586)
        at com.hazelcast.spi.impl.operationservice.impl.Invocation.doInvoke(Invocation.java:571)
        at com.hazelcast.spi.impl.operationservice.impl.Invocation.invoke0(Invocation.java:530)
        at com.hazelcast.spi.impl.operationservice.impl.Invocation.invoke(Invocation.java:220)
        at com.hazelcast.spi.impl.operationservice.impl.InvocationBuilderImpl.invoke(InvocationBuilderImpl.java:60)
        at com.hazelcast.client.impl.protocol.task.AbstractPartitionMessageTask.processMessage(AbstractPartitionMessageTask.java:67)
        at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.initializeAndProcessMessage(AbstractMessageTask.java:123)
        at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.doRun(AbstractMessageTask.java:111)
        at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.run(AbstractMessageTask.java:101)
        at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:161)
        at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:159)
        at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:127)
        at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.run(OperationThread.java:110)
Caused by: java.lang.IllegalArgumentException: There is no suitable accessor for 'eventType' on class 'java.lang.Long'
        at com.hazelcast.query.impl.getters.ReflectionHelper.createGetter(ReflectionHelper.java:168)
        ... 35 more

根据例外情况，我了解到Hazelcast正在尝试将索引应用于Value的{{1}}字段。

是否可以在IMap的{{1}}字段上放置索引？

Answer 1

尝试

        <indexes>
            <index ordered="true">__key.eventType</index>
        </indexes>

作为key-value存储区，通常会搜索值，因此正是索引所期望的。当您将eventType放在索引中时，它将在价值。您需要将其更改为__key.eventType才能使其在键中显示。

如果您需要对复合主键的一部分进行频繁的搜索访问（如索引实现），则可能需要检查主键结构的选择。

如果可以的话，还可以从3.11.2升级到3.12.1。幕后有一些查询方面的改进。

使用索引的Hazelcast分布式查询

1 个答案: