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我已经创建了一个 hive 表，现在我想将 snappy 压缩数据加载到表中。因此我做了以下事情：

SET mapreduce.output.fileoutputformat.compress.codec=org.apache.hadoop.io.compress.SnappyCodec;
SET hive.exec.compress.output=true;
SET mapreduce.output.fileoutputformat.compress=true;
CREATE TABLE toydata_table (id STRING, value STRING)  ROW FORMAT DELIMITED FIELDS TERMINATED BY ",";'

然后我创建了名为 toydata.csv 的 CSV 文件，该文件具有以下内容：

A,Value1
B,Value2
C,Value3

我用 snzip ( https://github.com/kubo/snzip )压缩了这个文件

/usr/local/bin/snzip -t snappy-java toydata.csv

产生toydata.csv.snappy. 完成此操作后，我返回 hive cli 并通过LOAD DATA LOCAL INPATH "toydata.csv.snappy" INTO TABLE toydata_table;. 但现在我想尝试从该表中查询并得到以下错误消息：

hive> select * from toydata_table;
OK
Exception in thread "main" java.lang.UnsatisfiedLinkError: org.apache.hadoop.util.NativeCodeLoader.buildSupportsSnappy()Z
    at org.apache.hadoop.util.NativeCodeLoader.buildSupportsSnappy(Native Method)
    at org.apache.hadoop.io.compress.SnappyCodec.checkNativeCodeLoaded(SnappyCodec.java:62)
    at org.apache.hadoop.io.compress.SnappyCodec.getDecompressorType(SnappyCodec.java:189)
    at org.apache.hadoop.io.compress.CodecPool.getDecompressor(CodecPool.java:175)
    at org.apache.hadoop.mapred.LineRecordReader.<init>(LineRecordReader.java:108)
    at org.apache.hadoop.mapred.TextInputFormat.getRecordReader(TextInputFormat.java:67)
    at org.apache.hadoop.hive.ql.exec.FetchOperator.getRecordReader(FetchOperator.java:433)
    at org.apache.hadoop.hive.ql.exec.FetchOperator.getNextRow(FetchOperator.java:515)
    at org.apache.hadoop.hive.ql.exec.FetchOperator.pushRow(FetchOperator.java:489)
    at org.apache.hadoop.hive.ql.exec.FetchTask.fetch(FetchTask.java:136)
    at org.apache.hadoop.hive.ql.Driver.getResults(Driver.java:1471)
    at org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:271)
    at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:216)
    at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:413)
    at org.apache.hadoop.hive.cli.CliDriver.executeDriver(CliDriver.java:781)
    at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:675)
    at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:614)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:212)

我用 gzip 做了同样的事情，使用 gzip 效果很好。那么，为什么这部分会失败呢？

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1 回答 1

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请在您的集群上安装 snappy 压缩编解码器。如果您想确认是否安装了 snappy，请在您的库中找到 libsnappy.so 文件。您还需要使用--auxpath参数启动 hive shell 并提供 snappy.jar.eg：hive --auxpath /home/user/snappy1.0.4.1.jar。

于 2014-08-07T18:11:34.900 回答