impala常见错误

1、使用insert插入字符串报错

ERROR: AnalysisException: Possible loss of precision for target table 'test.student'.

Expression ''e'' (type: STRING) would need to be cast to VARCHAR(22) for column 'name'

解决办法：

insert into student values(123, CAST('aaa' AS varchar(22)));

字符串转换下：CAST('xxx' AS varchar(12))

2、

E0127 19:28:25.289991 13469 impala-server.cc:339] ERROR: short-circuit local reads is disabled because

 - Impala cannot read or execute the parent directory of dfs.domain.socket.path

 - dfs.client.read.shortcircuit is not enabled.

ERROR: block location tracking is not properly enabled because

 - dfs.client.file-block-storage-locations.timeout is too low. It should be at least 3000.

E0127 19:28:25.290117 13469 impala-server.cc:341] Aborting Impala Server startup due to improper configuration

hdfs的配置文件hdfs-site.xml增加如下内容：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

< property > < name >dfs.client.read.shortcircuit</ name > < value >true</ value > </ property > < property > < name >dfs.domain.socket.path</ name > < value> /var/hdfs-sockets/dn </value>   #手动只需要创建 /var/hdfs-sockets目录，dn会自动创建 </ property > < property > < name >dfs.client.file-block-storage-locations.timeout</ name > < value >3000</ value > </ property > < property > < name >dfs.datanode.hdfs-blocks-metadata.enabled</ name > < value >true</ value > </ property >