For logs file I would suggest save as gziped text file first.  After 
aggregation, convert them into parquet by merging a few files. 



> On May 19, 2016, at 22:32, Deng Ching-Mallete <och...@apache.org> wrote:
> 
> IMO, it might be better to merge or compact the parquet files instead of 
> keeping lots of small files in the HDFS. Please refer to [1] for more info. 
> 
> We also encountered the same issue with the slow query, and it was indeed 
> caused by the many small parquet files. In our case, we were processing large 
> data sets with batch jobs instead of a streaming job. To solve our issue, we 
> just did a coalesce to reduce the number of partitions before saving as 
> parquet format. 
> 
> HTH,
> Deng
> 
> [1] http://blog.cloudera.com/blog/2009/02/the-small-files-problem/
> 
>> On Fri, May 20, 2016 at 1:50 PM, 王晓龙/01111515 <roland8...@cmbchina.com> 
>> wrote:
>> I’m using a spark streaming program to store log message into parquet file 
>> every 10 mins.
>> Now, when I query the parquet, it usually takes hundreds of thousands of 
>> stages to compute a single count.
>> I looked into the parquet file’s path and find a great amount of small files.
>> 
>> Do the small files caused the problem? Can I merge them, or is there a 
>> better way to solve it?
>> 
>> Lots of thanks.
>> 
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