TBLPROPERTIES ("parquet.compression"="lzo")
时间: 2023-09-21 15:05:01 浏览: 56
This statement is used to specify the compression algorithm to be used for storing data in a Parquet file. In this case, the compression algorithm is LZO (Lempel–Ziv–Oberhumer), which is a lossless data compression algorithm known for its fast decompression speed. Using LZO compression can help reduce the amount of storage space needed for Parquet files while still maintaining fast query performance.
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hive io.compression.codecs
Hive `io.compression.codecs` is a configuration property that specifies the list of compression codecs to be used by Hive for compressing and decompressing data. By default, Hive supports the following compression codecs:
- `org.apache.hadoop.io.compress.DefaultCodec`: The default codec for Hadoop, which uses the deflate algorithm for compression.
- `org.apache.hadoop.io.compress.GzipCodec`: The gzip codec for compression.
- `org.apache.hadoop.io.compress.BZip2Codec`: The bzip2 codec for compression.
- `org.apache.hadoop.io.compress.SnappyCodec`: The snappy codec for compression.
- `org.apache.hadoop.io.compress.Lz4Codec`: The lz4 codec for compression.
To specify the compression codecs, you can set the `io.compression.codecs` property in the `hive-site.xml` configuration file:
```
<property>
<name>io.compression.codecs</name>
<value>org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.BZip2Codec,org.apache.hadoop.io.compress.SnappyCodec,org.apache.hadoop.io.compress.Lz4Codec</value>
</property>
```
You can also specify the compression codec for a specific table or partition using the `STORED AS` clause in the `CREATE TABLE` statement:
```
CREATE TABLE my_table (
...
)
PARTITIONED BY (dt string)
STORED AS PARQUET
TBLPROPERTIES ("parquet.compression"="snappy");
```
In this example, the data for the `my_table` table is stored in the Parquet format with the snappy codec for compression.
spark2 屏蔽 org.apache.parquet.hadoop.codec.SnappyDecompressor.decompress
您好!我了解您的问题。如果您想在 Apache Spark 2 中屏蔽 `org.apache.parquet.hadoop.codec.SnappyDecompressor.decompress`,您可以通过在 Spark 配置文件中添加以下属性来实现:
```
spark.executor.extraJavaOptions=-Dio.netty.tryReflectionSetAccessible=true
```
这将启用 Spark 的 Netty 库来反射访问受保护的字段和方法,从而避免使用 Snappy 解压缩器。请注意,这可能会对性能产生一定影响,因此请谨慎使用。
希望这可以回答您的问题!如果您有任何其他问题,请随时问我。