com.hazelcast.query.LocalIndexStats Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021, 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;
import com.hazelcast.instance.LocalInstanceStats;
import com.hazelcast.internal.monitor.MemberState;
import com.hazelcast.map.LocalMapStats;
/**
* Provides local statistics for an index to be used by {@link MemberState}
* implementations.
*/
public interface LocalIndexStats extends LocalInstanceStats {
/**
* Returns the total number of queries served by the index.
*
* To calculate the index hit rate just divide the returned value by a value
* returned by {@link LocalMapStats#getQueryCount()}.
*
* The returned value may be less than the one returned by {@link
* #getHitCount()} since a single query may hit the same index more than once.
*/
long getQueryCount();
/**
* Returns the total number of hits into the index.
*
* The returned value may be greater than the one returned by {@link
* #getQueryCount} since a single query may hit the same index more than once.
*/
long getHitCount();
/**
* Returns the average hit latency (in nanoseconds) for the index.
*/
long getAverageHitLatency();
/**
* Returns the average selectivity of the hits served by the index.
*
* The returned value is in the range from 0.0 to 1.0. Values close to 1.0
* indicate a high selectivity meaning the index is efficient; values close
* to 0.0 indicate a low selectivity meaning the index efficiency is
* approaching an efficiency of a simple full scan.
*/
double getAverageHitSelectivity();
/**
* Returns the number of insert operations performed on the index.
*/
long getInsertCount();
/**
* Returns the total latency (in nanoseconds) of insert operations performed
* on the index.
*
* To compute the average latency divide the returned value by {@link
* #getInsertCount() insert operation count}.
*/
long getTotalInsertLatency();
/**
* Returns the number of update operations performed on the index.
*/
long getUpdateCount();
/**
* Returns the total latency (in nanoseconds) of update operations performed
* on the index.
*
* To compute the average latency divide the returned value by {@link
* #getUpdateCount() update operation count}.
*/
long getTotalUpdateLatency();
/**
* Returns the number of remove operations performed on the index.
*/
long getRemoveCount();
/**
* Returns the total latency (in nanoseconds) of remove operations performed
* on the index.
*
* To compute the average latency divide the returned value by {@link
* #getRemoveCount() remove operation count}.
*/
long getTotalRemoveLatency();
/**
* Returns the memory cost of the index in bytes.
*
* Currently, for on-heap indexes (OBJECT and BINARY storages), the returned
* value is just a best-effort approximation and doesn't indicate a precise
* on-heap memory usage of the index.
*/
long getMemoryCost();
}