org.apache.hadoop.hbase.HConstants#DEFAULT_HBASE_CLIENT_SCANNER_CACHING源码实例Demo

/**
 * Constructor
 * This is for internal testing purpose (using the default value).
 * In real usage, we should read the configuration from the Configuration object.
 */
@VisibleForTesting
protected ConnectionConfiguration() {
  this.writeBufferSize = WRITE_BUFFER_SIZE_DEFAULT;
  this.writeBufferPeriodicFlushTimeoutMs = WRITE_BUFFER_PERIODIC_FLUSH_TIMEOUT_MS_DEFAULT;
  this.writeBufferPeriodicFlushTimerTickMs = WRITE_BUFFER_PERIODIC_FLUSH_TIMERTICK_MS_DEFAULT;
  this.metaOperationTimeout = HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT;
  this.operationTimeout = HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT;
  this.scannerCaching = HConstants.DEFAULT_HBASE_CLIENT_SCANNER_CACHING;
  this.scannerMaxResultSize = HConstants.DEFAULT_HBASE_CLIENT_SCANNER_MAX_RESULT_SIZE;
  this.primaryCallTimeoutMicroSecond = 10000;
  this.replicaCallTimeoutMicroSecondScan = 1000000;
  this.metaReplicaCallTimeoutMicroSecondScan =
      HConstants.HBASE_CLIENT_META_REPLICA_SCAN_TIMEOUT_DEFAULT;
  this.retries = HConstants.DEFAULT_HBASE_CLIENT_RETRIES_NUMBER;
  this.clientScannerAsyncPrefetch = Scan.DEFAULT_HBASE_CLIENT_SCANNER_ASYNC_PREFETCH;
  this.maxKeyValueSize = MAX_KEYVALUE_SIZE_DEFAULT;
  this.readRpcTimeout = HConstants.DEFAULT_HBASE_RPC_TIMEOUT;
  this.writeRpcTimeout = HConstants.DEFAULT_HBASE_RPC_TIMEOUT;
  this.rpcTimeout = HConstants.DEFAULT_HBASE_RPC_TIMEOUT;
}
 

public int getScanCacheSize() {
  if (options != null) {
    if (options.getScanCacheSize() != HConstants.DEFAULT_HBASE_CLIENT_SCANNER_CACHING) {
      return options.getScanCacheSize();
    }
  }

  // Need to get default from config.
  return 10000;
}
 

private Object getValue(
    final Aggregation aggregation,
    final Filter filter,
    final DataTypeAdapter dataAdapter,
    final Short internalAdapterId,
    final HBaseDistributableFilter hdFilter,
    final boolean blockCaching,
    final int scanCacheSize,
    final String[] authorizations) throws IOException {
  final Scan scan = new Scan();
  scan.setMaxVersions(1);
  scan.setCacheBlocks(blockCaching);

  if (scanCacheSize != HConstants.DEFAULT_HBASE_CLIENT_SCANNER_CACHING) {
    scan.setCaching(scanCacheSize);
  }

  if (filter != null) {
    scan.setFilter(filter);
  }

  if (internalAdapterId != null) {
    scan.addFamily(StringUtils.stringToBinary(ByteArrayUtils.shortToString(internalAdapterId)));
  }

  if (authorizations != null) {
    scan.setAuthorizations(new Authorizations(authorizations));
  }
  env.getRegion().getCoprocessorHost().preScannerOpen(scan);
  try (InternalScanner scanner = env.getRegion().getScanner(scan)) {
    final List<Cell> results = new ArrayList<>();
    boolean hasNext;
    do {
      hasNext = scanner.next(results);
      if (!results.isEmpty()) {
        if (hdFilter != null) {
          if (dataAdapter != null) {
            final Object row = hdFilter.decodeRow(dataAdapter);

            if (row != null) {
              aggregation.aggregate(row);
            } else {
              LOGGER.error("DataAdapter failed to decode row");
            }
          } else {
            aggregation.aggregate(hdFilter.getPersistenceEncoding());
          }
        } else {
          aggregation.aggregate(null);
        }
        results.clear();
      }
    } while (hasNext);
  }
  return aggregation.getResult();
}