com.hazelcast.query.impl.InternalIndex Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2023, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.query.impl;
import com.hazelcast.internal.monitor.impl.PerIndexStats;
import com.hazelcast.query.impl.GlobalIndexPartitionTracker.PartitionStamp;
/**
* Provides the private index API.
*/
public interface InternalIndex extends Index {
/**
* Canonicalizes the given value for the purpose of a hash-based lookup.
*
* The method is used while performing InPredicate queries to canonicalize
* the set of values in question, so additional duplicate-eliminating
* post-processing step can be avoided.
*
* @param value the value to canonicalize.
* @return the canonicalized value.
*/
Comparable canonicalizeQueryArgumentScalar(Comparable value);
/**
* Returns {@code true} if the given partition is indexed by this index,
* {@code false} otherwise.
*/
boolean hasPartitionIndexed(int partitionId);
/**
* Returns {@code true} if the number of indexed partitions is equal to {@code
* ownedPartitionCount}, {@code false} otherwise.
*
* The method is used to check whether a global index is still being constructed concurrently
* so that some partitions are not indexed and query may suffer from entry misses.
* If the index construction is still in progress, a query optimizer ignores the index.
*
* The aforementioned race condition is not relevant to local off-heap indexes,
* since index construction is performed in partition threads.
*
* @param ownedPartitionCount a count of owned partitions a query runs on.
* Negative value indicates that the value is not defined.
*/
boolean allPartitionsIndexed(int ownedPartitionCount);
/**
* Notifies the index that a partition update is about to begin. Could be caused be either
* partition add (e.g. migration from another member, dynamic index creation), or partition
* remove (e.g. migration to another member).
*
* While in this state, the index cannot be queried by the SQL engine safely, because it
* will produce inconsistent results.
*
* Internally this call increments the counter of active partition updates. The counter
* is decremented by subsequent calls to {@link #markPartitionAsIndexed(int)} or
* {@link #markPartitionAsUnindexed(int)}. When the counter reaches zero, an index
* could be queried again.
*/
void beginPartitionUpdate();
/**
* Marks the given partition as indexed by this index.
*
* @param partitionId the ID of the partition to mark as indexed.
*/
void markPartitionAsIndexed(int partitionId);
/**
* Marks the given partition as unindexed by this index.
*
* @param partitionId the ID of the partition to mark as unindexed.
*/
void markPartitionAsUnindexed(int partitionId);
/**
* Returns the index stats associated with this index.
*/
PerIndexStats getPerIndexStats();
/**
* Get a monotonically increasing stamp and the partition ID set currently
* contained in the index. The received stamp is used later to verify that
* no partition was added or removed by calling to {@link
* #validatePartitionStamp(long)}.
*
* @return the stamp and the partitions, or {@code null}, if the index is
* currently being updated and cannot be safely read.
*/
PartitionStamp getPartitionStamp();
/**
* Verifies that the given partition stamp is still valid. It is valid iff there were
* no partition updates since the call to the {@link #getPartitionStamp()}
* that produced this stamp.
*
* @param stamp the value of {@link PartitionStamp#stamp} field
* @return {@code true} if the stamp is still valid, {@code false} otherwise
*/
boolean validatePartitionStamp(long stamp);
}