org.elasticsearch.index.fielddata.RamAccountingTermsEnum Maven / Gradle / Ivy
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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.index.fielddata;
import org.apache.lucene.index.FilteredTermsEnum;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.breaker.MemoryCircuitBreaker;
import org.elasticsearch.index.fielddata.AbstractIndexFieldData;
import java.io.IOException;
/**
* {@link TermsEnum} that takes a MemoryCircuitBreaker, increasing the breaker
* every time {@code .next(...)} is called. Proxies all methods to the original
* TermsEnum otherwise.
*/
public final class RamAccountingTermsEnum extends FilteredTermsEnum {
// Flush every 5mb
private static final long FLUSH_BUFFER_SIZE = 1024 * 1024 * 5;
private final MemoryCircuitBreaker breaker;
private final TermsEnum termsEnum;
private final AbstractIndexFieldData.PerValueEstimator estimator;
private long totalBytes;
private long flushBuffer;
public RamAccountingTermsEnum(TermsEnum termsEnum, MemoryCircuitBreaker breaker, AbstractIndexFieldData.PerValueEstimator estimator) {
super(termsEnum);
this.breaker = breaker;
this.termsEnum = termsEnum;
this.estimator = estimator;
this.totalBytes = 0;
this.flushBuffer = 0;
}
/**
* Always accept the term.
*/
@Override
protected AcceptStatus accept(BytesRef term) throws IOException {
return AcceptStatus.YES;
}
/**
* Flush the {@code flushBuffer} to the breaker, incrementing the total
* bytes and resetting the buffer.
*/
public void flush() {
breaker.addEstimateBytesAndMaybeBreak(this.flushBuffer);
this.totalBytes += this.flushBuffer;
this.flushBuffer = 0;
}
/**
* Proxy to the original next() call, but estimates the overhead of
* loading the next term.
*/
@Override
public BytesRef next() throws IOException {
BytesRef term = termsEnum.next();
if (term == null && this.flushBuffer != 0) {
// We have reached the end of the termsEnum, flush the buffer
flush();
} else {
this.flushBuffer += estimator.bytesPerValue(term);
if (this.flushBuffer >= FLUSH_BUFFER_SIZE) {
flush();
}
}
return term;
}
/**
* @return the total number of bytes that have been aggregated
*/
public long getTotalBytes() {
return this.totalBytes;
}
}