使用impala對大數據量查詢distinct的時候出現如下錯誤
5ab149d_24414dab2c19caca:e54b206c5ab149f_91001337-9d70-4c93-84ce-e7916c1ae804 failed with errno=2 description=Error(2): No such file or directory
Backend 4:Create file /tmp/impala-scratch/24414dab2c19caca:e54b206c5ab149d_24414dab2c19caca:e54b206c5ab149f_91001337-9d70-4c93-84ce-e7916c1ae804 failed with errno=2 description=Error(2): No such file or directory查閱文檔發現impala在大數據量處理時會用到磁盤保存中間數據
By default, intermediate files used during large sort, join, aggregation, or analytic function operations are stored in the directory /tmp/impala-scratch.
These files are removed when the operation finishes. (Multiple concurrent queries can perform operations that use the "spill
to disk" technique, without any name conflicts for these temporary files.) You can specify a different location by starting the impalad daemon
with the --scratch_dirs="path_to_directory" configuration
option or the equivalent configuration option in the Cloudera Manager user interface. You can specify a single directory, or a comma-separated list of directories. The scratch directories must be on the local filesystem, not in HDFS. You might specify different
directory paths for different hosts, depending on the capacity and speed of the available storage devices. Impala will not start if it cannot create or read and write files in the "scratch" directory.
If there is less than 1 GB free on the filesystem where that directory resides, Impala still runs, but writes a warning message to its log.
直接到各個impalad節點上創建/tmp/impala-scratch中間目錄，並賦予讀寫權限：
mkdir /tmp/impala-scratch
chmod 777 /tmp/impala-scratch
