org.apache.hudi.org.apache.hadoop.hbase.client.CompleteScanResultCache Maven / Gradle / Ivy
/**
* 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.hadoop.hbase.client;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.util.Bytes;
/**
* A scan result cache that only returns complete result.
*/
@InterfaceAudience.Private
class CompleteScanResultCache implements ScanResultCache {
private int numberOfCompleteRows;
private final List partialResults = new ArrayList<>();
private Result combine() throws IOException {
Result result = Result.createCompleteResult(partialResults);
partialResults.clear();
return result;
}
private Result[] prependCombined(Result[] results, int length) throws IOException {
if (length == 0) {
return new Result[] { combine() };
}
// the last part of a partial result may not be marked as partial so here we need to check if
// there is a row change.
int start;
if (Bytes.equals(partialResults.get(0).getRow(), results[0].getRow())) {
partialResults.add(results[0]);
start = 1;
length--;
} else {
start = 0;
}
Result[] prependResults = new Result[length + 1];
prependResults[0] = combine();
System.arraycopy(results, start, prependResults, 1, length);
return prependResults;
}
private Result[] updateNumberOfCompleteResultsAndReturn(Result... results) {
numberOfCompleteRows += results.length;
return results;
}
@Override
public Result[] addAndGet(Result[] results, boolean isHeartbeatMessage) throws IOException {
// If no results were returned it indicates that either we have the all the partial results
// necessary to construct the complete result or the server had to send a heartbeat message
// to the client to keep the client-server connection alive
if (results.length == 0) {
// If this response was an empty heartbeat message, then we have not exhausted the region
// and thus there may be more partials server side that still need to be added to the partial
// list before we form the complete Result
if (!partialResults.isEmpty() && !isHeartbeatMessage) {
return updateNumberOfCompleteResultsAndReturn(combine());
}
return EMPTY_RESULT_ARRAY;
}
// In every RPC response there should be at most a single partial result. Furthermore, if
// there is a partial result, it is guaranteed to be in the last position of the array.
Result last = results[results.length - 1];
if (last.mayHaveMoreCellsInRow()) {
if (partialResults.isEmpty()) {
partialResults.add(last);
return updateNumberOfCompleteResultsAndReturn(Arrays.copyOf(results, results.length - 1));
}
// We have only one result and it is partial
if (results.length == 1) {
// check if there is a row change
if (Bytes.equals(partialResults.get(0).getRow(), last.getRow())) {
partialResults.add(last);
return EMPTY_RESULT_ARRAY;
}
Result completeResult = combine();
partialResults.add(last);
return updateNumberOfCompleteResultsAndReturn(completeResult);
}
// We have some complete results
Result[] resultsToReturn = prependCombined(results, results.length - 1);
partialResults.add(last);
return updateNumberOfCompleteResultsAndReturn(resultsToReturn);
}
if (!partialResults.isEmpty()) {
return updateNumberOfCompleteResultsAndReturn(prependCombined(results, results.length));
}
return updateNumberOfCompleteResultsAndReturn(results);
}
@Override
public void clear() {
partialResults.clear();
}
@Override
public int numberOfCompleteRows() {
return numberOfCompleteRows;
}
}