apache/hadoop · error

hdfsRead failed and set errno %d

Error message

hdfsRead failed and set errno %d

What it means

Error "hdfsRead failed and set errno %d " thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs-tests/test_libhdfs_threaded.c:267

    errno = 0;
    EXPECT_UINT64_EQ(UINT64_C(0), readStats->totalBytesRead);
    EXPECT_UINT64_EQ(UINT64_C(0), readStats->totalLocalBytesRead);
    EXPECT_UINT64_EQ(UINT64_C(0), readStats->totalShortCircuitBytesRead);
    hdfsFileFreeReadStatistics(readStats);

    /* Verify that we can retrieve the hedged read metrics */
    EXPECT_ZERO(hdfsGetHedgedReadMetrics(fs, &hedgedMetrics));
    errno = 0;
    EXPECT_UINT64_EQ(UINT64_C(0), hedgedMetrics->hedgedReadOps);
    EXPECT_UINT64_EQ(UINT64_C(0), hedgedMetrics->hedgedReadOpsWin);
    EXPECT_UINT64_EQ(UINT64_C(0), hedgedMetrics->hedgedReadOpsInCurThread);
    hdfsFreeHedgedReadMetrics(hedgedMetrics);

    /* TODO: implement readFully and use it here */
    ret = hdfsRead(fs, file, tmp, sizeof(tmp));
    if (ret < 0) {
        ret = errno;
        fprintf(stderr, "hdfsRead failed and set errno %d\n", ret);
        return ret;
    }
    if (ret != expected) {
        fprintf(stderr, "hdfsRead was supposed to read %d bytes, but "
                "it read %d\n", ret, expected);
        return EIO;
    }
    EXPECT_ZERO(hdfsFileGetReadStatistics(file, &readStats));
    errno = 0;
    EXPECT_UINT64_EQ((uint64_t)expected, readStats->totalBytesRead);
    hdfsFileFreeReadStatistics(readStats);
    EXPECT_ZERO(hdfsFileClearReadStatistics(file));
    EXPECT_ZERO(hdfsFileGetReadStatistics(file, &readStats));
    EXPECT_UINT64_EQ((uint64_t)0, readStats->totalBytesRead);
    hdfsFileFreeReadStatistics(readStats);
    EXPECT_ZERO(memcmp(paths->prefix, tmp, expected));
    EXPECT_ZERO(hdfsCloseFile(fs, file));

View on GitHub (pinned to 2add963021)

Solutions

1. Check errno value printed: common causes are EACCES (permissions), ENOENT (missing file), EIO (NameNode/DataNode unreachable).
2. Verify the HDFS path exists and the test user has read permission before calling hdfsRead.
3. Ensure the libhdfs client is connected to a live NameNode (check hdfsConnect succeeded earlier in the test).

When it happens

Trigger: Raised inside the threaded libhdfs test when hdfsRead returns -1 during concurrent read workload.

Common situations: Occurs in test_libhdfs_threaded when the cluster is down, the test file was not written first, or many threads race on the same file handle.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/33c32d7e05863c3e. Report an issue: GitHub.