Usage¶
See the current usage using datafusion-cli --help:
Apache Arrow <dev@arrow.apache.org>
Command Line Client for DataFusion query engine.
USAGE:
datafusion-cli [OPTIONS]
OPTIONS:
-b, --batch-size <BATCH_SIZE>
The batch size of each query, or use DataFusion default
-c, --command <COMMAND>...
Execute the given command string(s), then exit
--color
Enables console syntax highlighting
-f, --file <FILE>...
Execute commands from file(s), then exit
--format <FORMAT>
[default: table] [possible values: csv, tsv, table, json, nd-json]
-h, --help
Print help information
-m, --memory-limit <MEMORY_LIMIT>
The memory pool limitation (e.g. '10g'), default to None (no limit)
--maxrows <MAXROWS>
The max number of rows to display for 'Table' format
[possible values: numbers(0/10/...), inf(no limit)] [default: 40]
--mem-pool-type <MEM_POOL_TYPE>
Specify the memory pool type 'greedy' or 'fair', default to 'greedy'
-p, --data-path <DATA_PATH>
Path to your data, default to current directory
-q, --quiet
Reduce printing other than the results and work quietly
-r, --rc <RC>...
Run the provided files on startup instead of ~/.datafusionrc
-V, --version
Print version information
Commands¶
Available commands inside DataFusion CLI are:
Quit
> \q
Help
> \?
ListTables
> \d
DescribeTable
> \d table_name
QuietMode
> \quiet [true|false]
list function
> \h
Search and describe function
> \h function
Supported SQL¶
In addition to the normal SQL supported in DataFusion, datafusion-cli also
supports additional statements and commands:
SHOW ALL [VERBOSE]¶
Show configuration options
> show all;
+-------------------------------------------------+---------+
| name | value |
+-------------------------------------------------+---------+
| datafusion.execution.batch_size | 8192 |
| datafusion.execution.coalesce_batches | true |
| datafusion.execution.time_zone | UTC |
| datafusion.explain.logical_plan_only | false |
| datafusion.explain.physical_plan_only | false |
| datafusion.optimizer.filter_null_join_keys | false |
| datafusion.optimizer.skip_failed_rules | true |
+-------------------------------------------------+---------+
SHOW <OPTION>>¶
Show specific configuration option
> show datafusion.execution.batch_size;
+-------------------------------------------------+---------+
| name | value |
+-------------------------------------------------+---------+
| datafusion.execution.batch_size | 8192 |
+-------------------------------------------------+---------+
SET <OPTION> TO <VALUE>¶
Set configuration options
> SET datafusion.execution.batch_size to 1024;
Configuration Options¶
All available configuration options can be seen using SHOW ALL as described above.
You can change the configuration options using environment
variables. datafusion-cli looks in the corresponding environment
variable with an upper case name and all . converted to _.
For example, to set datafusion.execution.batch_size to 1024 you
would set the DATAFUSION_EXECUTION_BATCH_SIZE environment variable
appropriately:
$ DATAFUSION_EXECUTION_BATCH_SIZE=1024 datafusion-cli
DataFusion CLI v12.0.0
> show all;
+-------------------------------------------------+---------+
| name | value |
+-------------------------------------------------+---------+
| datafusion.execution.batch_size | 1024 |
| datafusion.execution.coalesce_batches | true |
| datafusion.execution.time_zone | UTC |
| datafusion.explain.logical_plan_only | false |
| datafusion.explain.physical_plan_only | false |
| datafusion.optimizer.filter_null_join_keys | false |
| datafusion.optimizer.skip_failed_rules | true |
+-------------------------------------------------+---------+
8 rows in set. Query took 0.002 seconds.
You can change the configuration options using SET statement as well
$ datafusion-cli
DataFusion CLI v13.0.0
> show datafusion.execution.batch_size;
+---------------------------------+---------+
| name | value |
+---------------------------------+---------+
| datafusion.execution.batch_size | 8192 |
+---------------------------------+---------+
1 row in set. Query took 0.011 seconds.
> set datafusion.execution.batch_size to 1024;
0 rows in set. Query took 0.000 seconds.
> show datafusion.execution.batch_size;
+---------------------------------+---------+
| name | value |
+---------------------------------+---------+
| datafusion.execution.batch_size | 1024 |
+---------------------------------+---------+
1 row in set. Query took 0.005 seconds.
Functions¶
datafusion-cli comes with build-in functions that are not included in the
DataFusion SQL engine. These functions are:
parquet_metadata¶
The parquet_metadata table function can be used to inspect detailed metadata
about a parquet file such as statistics, sizes, and other information. This can
be helpful to understand how parquet files are structured.
For example, to see information about the "WatchID" column in the
hits.parquet file, you can use:
SELECT path_in_schema, row_group_id, row_group_num_rows, stats_min, stats_max, total_compressed_size
FROM parquet_metadata('hits.parquet')
WHERE path_in_schema = '"WatchID"'
LIMIT 3;
+----------------+--------------+--------------------+---------------------+---------------------+-----------------------+
| path_in_schema | row_group_id | row_group_num_rows | stats_min | stats_max | total_compressed_size |
+----------------+--------------+--------------------+---------------------+---------------------+-----------------------+
| "WatchID" | 0 | 450560 | 4611687214012840539 | 9223369186199968220 | 3883759 |
| "WatchID" | 1 | 612174 | 4611689135232456464 | 9223371478009085789 | 5176803 |
| "WatchID" | 2 | 344064 | 4611692774829951781 | 9223363791697310021 | 3031680 |
+----------------+--------------+--------------------+---------------------+---------------------+-----------------------+
3 rows in set. Query took 0.053 seconds.
The returned table has the following columns for each row for each column chunk in the file. Please refer to the Parquet Documentation for more information.
column_name |
data_type |
Description |
|---|---|---|
filename |
Utf8 |
Name of the file |
row_group_id |
Int64 |
Row group index the column chunk belongs to |
row_group_num_rows |
Int64 |
Count of rows stored in the row group |
row_group_num_columns |
Int64 |
Total number of columns in the row group (same for all row groups) |
row_group_bytes |
Int64 |
Number of bytes used to store the row group (not including metadata) |
column_id |
Int64 |
ID of the column |
file_offset |
Int64 |
Offset within the file that this column chunk’s data begins |
num_values |
Int64 |
Total number of values in this column chunk |
path_in_schema |
Utf8 |
“Path” (column name) of the column chunk in the schema |
type |
Utf8 |
Parquet data type of the column chunk |
stats_min |
Utf8 |
The minimum value for this column chunk, if stored in the statistics, cast to a string |
stats_max |
Utf8 |
The maximum value for this column chunk, if stored in the statistics, cast to a string |
stats_null_count |
Int64 |
Number of null values in this column chunk, if stored in the statistics |
stats_distinct_count |
Int64 |
Number of distinct values in this column chunk, if stored in the statistics |
stats_min_value |
Utf8 |
Same as |
stats_max_value |
Utf8 |
Same as |
compression |
Utf8 |
Block level compression (e.g. |
encodings |
Utf8 |
All block level encodings (e.g. |
index_page_offset |
Int64 |
Offset in the file of the |
dictionary_page_offset |
Int64 |
Offset in the file of the dictionary page, if any |
data_page_offset |
Int64 |
Offset in the file of the first data page, if any |
total_compressed_size |
Int64 |
Number of bytes the column chunk’s data after encoding and compression (what is stored in the file) |
total_uncompressed_size |
Int64 |
Number of bytes the column chunk’s data after encoding |
+————————-+———–+————-+