Example usage for org.apache.hadoop.hdfs.shortcircuit ShortCircuitReplicaInfo getReplica

Introduction

In this page you can find the example usage for org.apache.hadoop.hdfs.shortcircuit ShortCircuitReplicaInfo getReplica.

Prototype

public ShortCircuitReplica getReplica() 

Source Link

Usage

From source file:BlockReaderFactory.java

License:Apache License

private BlockReader getBlockReaderLocal() throws InvalidToken {
    if (LOG.isTraceEnabled()) {
        LOG.trace(this + ": trying to construct a BlockReaderLocal " + "for short-circuit reads.");
    }/*from w  w  w. j  a  v  a 2  s. c o  m*/
    if (pathInfo == null) {
        pathInfo = clientContext.getDomainSocketFactory().getPathInfo(inetSocketAddress, conf);
    }
    if (!pathInfo.getPathState().getUsableForShortCircuit()) {
        PerformanceAdvisory.LOG.debug(this + ": " + pathInfo + " is not "
                + "usable for short circuit; giving up on BlockReaderLocal.");
        return null;
    }
    ShortCircuitCache cache = clientContext.getShortCircuitCache();
    ExtendedBlockId key = new ExtendedBlockId(block.getBlockId(), block.getBlockPoolId());
    ShortCircuitReplicaInfo info = cache.fetchOrCreate(key, this);
    InvalidToken exc = info.getInvalidTokenException();
    if (exc != null) {
        if (LOG.isTraceEnabled()) {
            LOG.trace(this + ": got InvalidToken exception while trying to " + "construct BlockReaderLocal via "
                    + pathInfo.getPath());
        }
        throw exc;
    }
    if (info.getReplica() == null) {
        if (LOG.isTraceEnabled()) {
            PerformanceAdvisory.LOG.debug(this + ": failed to get " + "ShortCircuitReplica. Cannot construct "
                    + "BlockReaderLocal via " + pathInfo.getPath());
        }
        return null;
    }
    return new BlockReaderLocal.Builder(conf).setFilename(fileName).setBlock(block).setStartOffset(startOffset)
            .setShortCircuitReplica(info.getReplica()).setVerifyChecksum(verifyChecksum)
            .setCachingStrategy(cachingStrategy).setStorageType(storageType).build();
}

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