Querying a File System Introduction
Files and directories are like standard SQL tables to Drill. You can specify a
file system "database" as a prefix in queries when you refer to objects across
databases. In Drill, a file system database consists of a storage plugin name
followed by an optional workspace name, for example
The following example shows a query on a file system database in a Hadoop distributed file system:
SELECT * FROM hdfs.logs.`AppServerLogs/20104/Jan/01/part0001.txt`;
The default dfs storage plugin configuration registered with Drill has a
default workspace. If you query data in the default workspace, you do not
need to include the workspace in the query. Refer to
Workspaces for
more information.
Drill supports the following file types:
- Plain text files, including:
- Comma-separated values (CSV, type: text)
- Tab-separated values (TSV, type: text)
- Pipe-separated values (PSV, type: text)
- Structured data files:
- Avro(type: avro)
- JSON (type: json)
- Parquet (type: parquet)
The extensions for these file types must match the configuration settings for
your registered storage plugins. For example, PSV files may be defined with a
.tbl extension, while CSV files are defined with a .csv extension.