DESCRIBE statement
The DESCRIBE statement displays metadata about a table, such as the
column names and their data types. In Impala 2.3 and higher versions, you can
specify the name of a complex type column, which takes the form of a dotted path. The path
might include multiple components in the case of a nested type definition.
In Impala 2.5 and higher versions, the DESCRIBE DATABASE form
can display information about a database.
Syntax:
DESCRIBE [DATABASE] [FORMATTED|EXTENDED] object_name
object_name ::=
[db_name.]table_name[.complex_col_name ...]
| db_name
You can use the abbreviation DESC for the DESCRIBE
statement.
The DESCRIBE FORMATTED variation displays additional information
in a format familiar to users of Apache Hive. The additional information includes low-level
details such as whether the table is internal or external, creation date, the file format,
the location of the data in HDFS, whether the object is a table or a view, and the text of
the query from the view definition.
Describing databases:
By default, the DESCRIBE output for a database includes the
location and the comment, which can be set by the LOCATION and
COMMENT clauses on the CREATE DATABASE statement.
The additional information displayed by the FORMATTED or
EXTENDED keyword includes the HDFS user ID that is considered the owner
of the database, and any optional database properties. You can specify the properties using
the WITH DBPROPERTIES clause if the database is created using a Hive
CREATE DATABASE statement. Impala currently does not set or perform any
special processing based on those properties.
The additional information displayed by the
FORMATTED or EXTENDED keyword includes the HDFS user ID
that is considered the owner of the database, and any optional database properties. You can
set the properties by using the WITH DBPROPERTIES clause of the
CREATE DATABASE statement, or on an existing database by using
SET DBPROPERTIES clause of the ALTER DATABASE statement,
in either Impala or Hive. Impala does not perform any special processing based on those
properties.
The following examples show the variations in syntax and output for describing databases. This feature is available in Impala 2.5 and higher versions.
describe database default;
+---------+----------------------+-----------------------+
| name | location | comment |
+---------+----------------------+-----------------------+
| default | /user/hive/warehouse | Default Hive database |
+---------+----------------------+-----------------------+
describe database formatted default;
+---------+----------------------+-----------------------+
| name | location | comment |
+---------+----------------------+-----------------------+
| default | /user/hive/warehouse | Default Hive database |
| Owner: | | |
| | public | ROLE |
+---------+----------------------+-----------------------+
describe database extended default;
+---------+----------------------+-----------------------+
| name | location | comment |
+---------+----------------------+-----------------------+
| default | /user/hive/warehouse | Default Hive database |
| Owner: | | |
| | public | ROLE |
+---------+----------------------+-----------------------+
Describing tables:
If the DATABASE keyword is omitted, the DESCRIBE
statement refers to a table by default.
If you have the SELECT privilege on a subset of the table columns and no
other relevant table, database, or server-level privileges, DESCRIBE
returns the data from the columns you have access to.
If you have the SELECT privilege on a subset of the table columns and no
other relevant table, database, server-level privileges, DESCRIBE
FORMATTED/EXTENDED does not return the LOCATION field. The
LOCATION data is displays if you have any privilege on the table, the
containing database, or the server.
-- By default, the table is assumed to be in the current database.
describe my_table;
+------+--------+---------+
| name | type | comment |
+------+--------+---------+
| x | int | |
| s | string | |
+------+--------+---------+
-- Use a fully qualified table name to specify a table in any database.
describe my_database.my_table;
+------+--------+---------+
| name | type | comment |
+------+--------+---------+
| x | int | |
| s | string | |
+------+--------+---------+
-- The formatted or extended output includes additional useful information.
-- The LOCATION field is especially useful to know for DDL statements and HDFS commands
-- during ETL jobs. (The LOCATION includes a full hdfs:// URL, omitted here for readability.)
describe formatted my_table;
+------------------------------+----------------------------------------------+----------------------+
| name | type | comment |
+------------------------------+----------------------------------------------+----------------------+
| # col_name | data_type | comment |
| | NULL | NULL |
| x | int | NULL |
| s | string | NULL |
| | NULL | NULL |
| # Detailed Table Information | NULL | NULL |
| Database: | my_database | NULL |
| Owner: | jrussell | NULL |
| CreateTime: | Fri Mar 18 15:58:00 PDT 2016 | NULL |
| LastAccessTime: | UNKNOWN | NULL |
| Protect Mode: | None | NULL |
| Retention: | 0 | NULL |
| Location: | /user/hive/warehouse/my_database.db/my_table | NULL |
| Table Type: | MANAGED_TABLE | NULL |
| Table Parameters: | NULL | NULL |
| | transient_lastDdlTime | 1458341880 |
| | NULL | NULL |
| # Storage Information | NULL | NULL |
| SerDe Library: | org. ... .LazySimpleSerDe | NULL |
| InputFormat: | org.apache.hadoop.mapred.TextInputFormat | NULL |
| OutputFormat: | org. ... .HiveIgnoreKeyTextOutputFormat | NULL |
| Compressed: | No | NULL |
| Num Buckets: | 0 | NULL |
| Bucket Columns: | [] | NULL |
| Sort Columns: | [] | NULL |
+------------------------------+----------------------------------------------+----------------------+
Complex type considerations:
Because the column definitions for complex types can become long, particularly
when such types are nested, the DESCRIBE statement uses special formatting
for complex type columns to make the output readable.
For the ARRAY, STRUCT, and
MAP types available in Impala 2.3 and higher versions, the
DESCRIBE output is formatted to avoid excessively long lines for multiple
fields within a STRUCT, or a nested sequence of complex types.
You can pass a multi-part qualified name to
DESCRIBE to specify an ARRAY, STRUCT,
or MAP column and visualize its structure as if it were a table. For
example, if table T1 contains an ARRAY column
A1, you could issue the statement DESCRIBE t1.a1. If
table T1 contained a STRUCT column S1,
and a field F1 within the STRUCT was a
MAP, you could issue the statement DESCRIBE t1.s1.f1. An
ARRAY is displayed as a two-column table, with ITEM and
POS columns. A STRUCT is displayed as a table with each
field representing a column in the table. A MAP is displayed as a
two-column table, with KEY and VALUE columns.
In this example, the DESCRIBE output for a table contains a
single top-level column of each complex type.
create table t1 (x int, a array<int>, s struct<f1: string, f2: bigint>, m map<string,int>) stored as parquet;
describe t1;
+------+-----------------+---------+
| name | type | comment |
+------+-----------------+---------+
| x | int | |
| a | array<int> | |
| s | struct< | |
| | f1:string, | |
| | f2:bigint | |
| | > | |
| m | map<string,int> | |
+------+-----------------+---------+
The following examples show how to drill down into the layouts of complex
types, including using multi-part names to examine the definitions of nested types. The
< > delimiters identify the columns with complex types. These are
the columns where you can descend to another level to see the parts that make up the complex
type. This technique helps you to understand the multi-part names you use as table
references in queries involving complex types, and the corresponding column names you refer
to in the SELECT list. These tables are from the nested TPC-H schema. For
more information, see Sample schema and data for experimenting with Impala complex
types.
The REGION table contains an ARRAY of
STRUCT elements:
-
The first
DESCRIBEspecifies the table name, to display the definition of each top-level column. -
The second
DESCRIBEspecifies the name of a complex column,REGION.R_NATIONS, showing that when you include the name of anARRAYcolumn in aFROMclause, that table reference acts as a two-column table with columnsITEMandPOS. -
The final
DESCRIBEspecifies the fully qualified name of theITEMfield, to display the layout of its underlyingSTRUCTtype in table format, with the fields mapped to column names.
-- #1: The overall layout of the entire table.
describe region;
+-------------+-------------------------+---------+
| name | type | comment |
+-------------+-------------------------+---------+
| r_regionkey | smallint | |
| r_name | string | |
| r_comment | string | |
| r_nations | array<struct< | |
| | n_nationkey:smallint, | |
| | n_name:string, | |
| | n_comment:string | |
| | >> | |
+-------------+-------------------------+---------+
-- #2: The ARRAY column within the table.
describe region.r_nations;
+------+-------------------------+---------+
| name | type | comment |
+------+-------------------------+---------+
| item | struct< | |
| | n_nationkey:smallint, | |
| | n_name:string, | |
| | n_comment:string | |
| | > | |
| pos | bigint | |
+------+-------------------------+---------+
-- #3: The STRUCT that makes up each ARRAY element.
-- The fields of the STRUCT act like columns of a table.
describe region.r_nations.item;
+-------------+----------+---------+
| name | type | comment |
+-------------+----------+---------+
| n_nationkey | smallint | |
| n_name | string | |
| n_comment | string | |
+-------------+----------+---------+
The CUSTOMER table contains an ARRAY of
STRUCT elements, where one field in the STRUCT is
another ARRAY of STRUCT elements:
-
The initial
DESCRIBEspecifies only the table name. -
The second
DESCRIBEspecifies the qualified name of the complex column,CUSTOMER.C_ORDERS, showing how anARRAYis represented as a two-column table with columnsITEMandPOS. -
The third
DESCRIBEspecifies the qualified name of theITEMof theARRAYcolumn, to see the structure of the nestedARRAYwith two parts,ITEMandPOS. Because theARRAYcontains aSTRUCT, the layout of theSTRUCTis displayed. -
The fourth and fifth
DESCRIBEstatements drill down into aSTRUCTfield that is itself a complex type, anARRAYofSTRUCT. TheITEMportion of the qualified name is only required when theARRAYelements are anonymous. The fields of theSTRUCTgive names to any other complex types nested inside theSTRUCT. Therefore, theDESCRIBEparametersCUSTOMER.C_ORDERS.ITEM.O_LINEITEMSandCUSTOMER.C_ORDERS.O_LINEITEMSare equivalent.For brevity, leave out the
ITEMportion of a qualified name when it is not required. -
The final
DESCRIBEshows the layout of the deeply nestedSTRUCTtype. Because no more complex types are nested inside thisSTRUCT, this is the deepest you can drill down into the layout for this table.
-- #1: The overall layout of the entire table.
describe customer;
+--------------+------------------------------------+
| name | type |
+--------------+------------------------------------+
| c_custkey | bigint |
... more scalar columns ...
| c_orders | array<struct< |
| | o_orderkey:bigint, |
| | o_orderstatus:string, |
| | o_totalprice:decimal(12,2), |
| | o_orderdate:string, |
| | o_orderpriority:string, |
| | o_clerk:string, |
| | o_shippriority:int, |
| | o_comment:string, |
| | o_lineitems:array<struct< |
| | l_partkey:bigint, |
| | l_suppkey:bigint, |
| | l_linenumber:int, |
| | l_quantity:decimal(12,2), |
| | l_extendedprice:decimal(12,2), |
| | l_discount:decimal(12,2), |
| | l_tax:decimal(12,2), |
| | l_returnflag:string, |
| | l_linestatus:string, |
| | l_shipdate:string, |
| | l_commitdate:string, |
| | l_receiptdate:string, |
| | l_shipinstruct:string, |
| | l_shipmode:string, |
| | l_comment:string |
| | >> |
| | >> |
+--------------+------------------------------------+
-- #2: The ARRAY column within the table.
describe customer.c_orders;
+------+------------------------------------+
| name | type |
+------+------------------------------------+
| item | struct< |
| | o_orderkey:bigint, |
| | o_orderstatus:string, |
... more struct fields ...
| | o_lineitems:array<struct< |
| | l_partkey:bigint, |
| | l_suppkey:bigint, |
... more nested struct fields ...
| | l_comment:string |
| | >> |
| | > |
| pos | bigint |
+------+------------------------------------+
-- #3: The STRUCT that makes up each ARRAY element.
-- The fields of the STRUCT act like columns of a table.
describe customer.c_orders.item;
+-----------------+----------------------------------+
| name | type |
+-----------------+----------------------------------+
| o_orderkey | bigint |
| o_orderstatus | string |
| o_totalprice | decimal(12,2) |
| o_orderdate | string |
| o_orderpriority | string |
| o_clerk | string |
| o_shippriority | int |
| o_comment | string |
| o_lineitems | array<struct< |
| | l_partkey:bigint, |
| | l_suppkey:bigint, |
... more struct fields ...
| | l_comment:string |
| | >> |
+-----------------+----------------------------------+
-- #4: The ARRAY nested inside the STRUCT elements of the first ARRAY.
describe customer.c_orders.item.o_lineitems;
+------+----------------------------------+
| name | type |
+------+----------------------------------+
| item | struct< |
| | l_partkey:bigint, |
| | l_suppkey:bigint, |
... more struct fields ...
| | l_comment:string |
| | > |
| pos | bigint |
+------+----------------------------------+
-- #5: Shorter form of the previous DESCRIBE. Omits the .ITEM portion of the name
-- because O_LINEITEMS and other field names provide a way to refer to things
-- inside the ARRAY element.
describe customer.c_orders.o_lineitems;
+------+----------------------------------+
| name | type |
+------+----------------------------------+
| item | struct< |
| | l_partkey:bigint, |
| | l_suppkey:bigint, |
... more struct fields ...
| | l_comment:string |
| | > |
| pos | bigint |
+------+----------------------------------+
-- #6: The STRUCT representing ARRAY elements nested inside
-- another ARRAY of STRUCTs. The lack of any complex types
-- in this output means this is as far as DESCRIBE can
-- descend into the table layout.
describe customer.c_orders.o_lineitems.item;
+-----------------+---------------+
| name | type |
+-----------------+---------------+
| l_partkey | bigint |
| l_suppkey | bigint |
... more scalar columns ...
| l_comment | string |
+-----------------+---------------+
Usage notes:
After the impalad daemons are restarted, the first query against a table
can take longer than the subsequent queries, because the metadata for the table is loaded
before the query is processed. This one-time delay for each table can cause misleading
results in benchmark tests or cause unnecessary concern. To warm up the Impala metadata
cache, you can issue a DESCRIBE statement in advance for each table you
intend to access later.
When you are dealing with data files stored in HDFS, knowing details such as the path of
the data files for an Impala table, and the hostname for the namenode can be important. You
can get this information from the DESCRIBE FORMATTED output. You specify
HDFS URIs or path specifications with statements such as LOAD DATA and the
LOCATION clause of CREATE TABLE or ALTER
TABLE. You might also use HDFS URIs or paths with Linux commands such as
hadoop and hdfs to copy, rename, or perform other
action on data files in HDFS.
If you connect to different Impala nodes within an
impala-shell session for load-balancing purposes, you can enable the
SYNC_DDL query option to ensure that each DDL statement waits until all
Impala nodes receive new or changed metadata before returning.
Each table can also have associated table statistics and column statistics. To
see these categories of information, use the SHOW TABLE STATS
table_name and SHOW COLUMN STATS
table_name statements. For more information, see SHOW statement.
Examples:
The following example shows the results of both standard DESCRIBE and
DESCRIBE FORMATTED statements for different kinds of schema objects:
DESCRIBEfor a table or a view returns the name, type, and comment for each of the columns. For a view, if the column value is computed by an expression, the column name is automatically generated as_c0,_c1, and so on depending on the ordinal number of the column.- A table created with no special format or storage clauses is designated as a
MANAGED_TABLE(an internal table in Impala terminology). Its data files are stored in an HDFS directory under the default Hive data directory. By default, it uses Text data format. - A view is designated as
VIRTUAL_VIEWinDESCRIBE FORMATTEDoutput. Some of its properties areNULLor blank because they are inherited from the base table. The text of the query that defines the view is part of theDESCRIBE FORMATTEDoutput. - A table with additional clauses in the
CREATE TABLEstatement has differences inDESCRIBE FORMATTEDoutput. The output forT2includes theEXTERNAL_TABLEkeyword because of theCREATE EXTERNAL TABLEsyntax, and differentInputFormatandOutputFormatfields to reflect the Parquet file format.
[localhost:21000] > create table t1 (x int, y int, s string);
Query: create table t1 (x int, y int, s string)
[localhost:21000] > describe t1;
Query: describe t1
Query finished, fetching results ...
+------+--------+---------+
| name | type | comment |
+------+--------+---------+
| x | int | |
| y | int | |
| s | string | |
+------+--------+---------+
Returned 3 row(s) in 0.13s
[localhost:21000] > describe formatted t1;
Query: describe formatted t1
Query finished, fetching results ...
+------------------------------+--------------------------------------------+------------+
| name | type | comment |
+------------------------------+--------------------------------------------+------------+
| # col_name | data_type | comment |
| | NULL | NULL |
| x | int | None |
| y | int | None |
| s | string | None |
| | NULL | NULL |
| # Detailed Table Information | NULL | NULL |
| Database: | describe_formatted | NULL |
| Owner: | doc_demo | NULL |
| CreateTime: | Mon Jul 22 17:03:16 EDT 2013 | NULL |
| LastAccessTime: | UNKNOWN | NULL |
| Protect Mode: | None | NULL |
| Retention: | 0 | NULL |
| Location: | hdfs://127.0.0.1:8020/user/hive/warehouse/ | |
| | describe_formatted.db/t1 | NULL |
| Table Type: | MANAGED_TABLE | NULL |
| Table Parameters: | NULL | NULL |
| | transient_lastDdlTime | 1374526996 |
| | NULL | NULL |
| # Storage Information | NULL | NULL |
| SerDe Library: | org.apache.hadoop.hive.serde2.lazy. | |
| | LazySimpleSerDe | NULL |
| InputFormat: | org.apache.hadoop.mapred.TextInputFormat | NULL |
| OutputFormat: | org.apache.hadoop.hive.ql.io. | |
| | HiveIgnoreKeyTextOutputFormat | NULL |
| Compressed: | No | NULL |
| Num Buckets: | 0 | NULL |
| Bucket Columns: | [] | NULL |
| Sort Columns: | [] | NULL |
+------------------------------+--------------------------------------------+------------+
Returned 26 row(s) in 0.03s
[localhost:21000] > create view v1 as select x, upper(s) from t1;
Query: create view v1 as select x, upper(s) from t1
[localhost:21000] > describe v1;
Query: describe v1
Query finished, fetching results ...
+------+--------+---------+
| name | type | comment |
+------+--------+---------+
| x | int | |
| _c1 | string | |
+------+--------+---------+
Returned 2 row(s) in 0.10s
[localhost:21000] > describe formatted v1;
Query: describe formatted v1
Query finished, fetching results ...
+------------------------------+------------------------------+----------------------+
| name | type | comment |
+------------------------------+------------------------------+----------------------+
| # col_name | data_type | comment |
| | NULL | NULL |
| x | int | None |
| _c1 | string | None |
| | NULL | NULL |
| # Detailed Table Information | NULL | NULL |
| Database: | describe_formatted | NULL |
| Owner: | doc_demo | NULL |
| CreateTime: | Mon Jul 22 16:56:38 EDT 2013 | NULL |
| LastAccessTime: | UNKNOWN | NULL |
| Protect Mode: | None | NULL |
| Retention: | 0 | NULL |
| Table Type: | VIRTUAL_VIEW | NULL |
| Table Parameters: | NULL | NULL |
| | transient_lastDdlTime | 1374526598 |
| | NULL | NULL |
| # Storage Information | NULL | NULL |
| SerDe Library: | null | NULL |
| InputFormat: | null | NULL |
| OutputFormat: | null | NULL |
| Compressed: | No | NULL |
| Num Buckets: | 0 | NULL |
| Bucket Columns: | [] | NULL |
| Sort Columns: | [] | NULL |
| | NULL | NULL |
| # View Information | NULL | NULL |
| View Original Text: | SELECT x, upper(s) FROM t1 | NULL |
| View Expanded Text: | SELECT x, upper(s) FROM t1 | NULL |
+------------------------------+------------------------------+----------------------+
Returned 28 row(s) in 0.03s
[localhost:21000] > create external table t2 (x int, y int, s string) stored as parquet location '/user/doc_demo/sample_data';
[localhost:21000] > describe formatted t2;
Query: describe formatted t2
Query finished, fetching results ...
+------------------------------+----------------------------------------------------+------------+
| name | type | comment |
+------------------------------+----------------------------------------------------+------------+
| # col_name | data_type | comment |
| | NULL | NULL |
| x | int | None |
| y | int | None |
| s | string | None |
| | NULL | NULL |
| # Detailed Table Information | NULL | NULL |
| Database: | describe_formatted | NULL |
| Owner: | doc_demo | NULL |
| CreateTime: | Mon Jul 22 17:01:47 EDT 2013 | NULL |
| LastAccessTime: | UNKNOWN | NULL |
| Protect Mode: | None | NULL |
| Retention: | 0 | NULL |
| Location: | hdfs://127.0.0.1:8020/user/doc_demo/sample_data | NULL |
| Table Type: | EXTERNAL_TABLE | NULL |
| Table Parameters: | NULL | NULL |
| | EXTERNAL | TRUE |
| | transient_lastDdlTime | 1374526907 |
| | NULL | NULL |
| # Storage Information | NULL | NULL |
| SerDe Library: | org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe | NULL |
| InputFormat: | com.cloudera.impala.hive.serde.ParquetInputFormat | NULL |
| OutputFormat: | com.cloudera.impala.hive.serde.ParquetOutputFormat | NULL |
| Compressed: | No | NULL |
| Num Buckets: | 0 | NULL |
| Bucket Columns: | [] | NULL |
| Sort Columns: | [] | NULL |
+------------------------------+----------------------------------------------------+------------+
Returned 27 row(s) in 0.17sCancellation: Cannot be cancelled.
HDFS permissions:
The user ID that the impalad daemon runs under,
typically the impala user, must have read and execute permissions for all
directories that are part of the table. A table could span multiple different HDFS
directories if it is partitioned. The directories could be widely scattered because a
partition can reside in an arbitrary HDFS directory based on its LOCATION
attribute.
Cloudera Manager considerations:
A change in the behavior of metadata loading in Impala 2.9 could lead to certain long-running statements being left out of the Cloudera Manager list of Impala queries until the statements are completed.
In versions lower than Impala 2.9, statements such as DESCRIBE could cause
the Impala web UI, and Cloudera Manager monitoring pages that rely on information from the
web UI, to become unresponsive while they ran. The first time Impala references a large
table, for example one with thousands of partitions, the statement might take longer than
normal while the metadata for the table is loaded. In Impala 2.9 and higher versions, the
Impala web UI and associated Cloudera Manager monitoring pages are more responsive while a
metadata loading operation is in progress.
Although the statement that loads the metadata
is displayed on the Impala web UI /queries page immediately, it is
not displayed in the Cloudera Manager list of queries until the metadata is finished
loading. For example, the first DESCRIBE of a large partitioned table might
take 30 minutes due to metadata loading, and the statement is not displayed in Cloudera
Manager during those 30 minutes.
Kudu considerations:
The information displayed for Kudu tables includes the following additional attributes that are only applicable for Kudu tables:
- Whether the column is part of the primary key. Every Kudu table has a
truevalue here for at least one column. Multipletruevalues could exist, for tables with composite primary keys. - Whether the column is nullable. Specified by the
NULLorNOT NULLattributes on theCREATE TABLEstatement. Columns that are part of the primary key are automatically non-nullable. - The default value, if any, for the column. Specified by the
DEFAULTattribute on theCREATE TABLEstatement. If the default value isNULL, this column remains blank because aNULLdefault is implied when a column is nullable and has no explicit default value. - The encoding used for values in the column. Specified by the
ENCODINGattribute on theCREATE TABLEstatement. - The compression used for values in the column. Specified by the
COMPRESSIONattribute on theCREATE TABLEstatement. - The block size (in bytes) used for the underlying Kudu storage layer for the column.
Specified by the
BLOCK_SIZEattribute on theCREATE TABLEstatement.
The following example shows DESCRIBE output for a simple Kudu
table, with a single-column primary key and all column attributes left with their default
values:
describe million_rows;
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
| name | type | comment | primary_key | nullable | default_value | encoding | compression | block_size |
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
| id | string | | true | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| s | string | | false | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
The following example shows DESCRIBE output for a Kudu table
with a two-column primary key, and Kudu-specific attributes applied to some columns:
create table kudu_describe_example
(
c1 int, c2 int,
c3 string, c4 string not null, c5 string default 'n/a', c6 string default '',
c7 bigint not null, c8 bigint null default null, c9 bigint default -1 encoding bit_shuffle,
primary key(c1,c2)
)
partition by hash (c1, c2) partitions 10 stored as kudu;
describe kudu_describe_example;
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
| name | type | comment | primary_key | nullable | default_value | encoding | compression | block_size |
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
| c1 | int | | true | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c2 | int | | true | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c3 | string | | false | true | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c4 | string | | false | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c5 | string | | false | true | n/a | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c6 | string | | false | true | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c7 | bigint | | false | false | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c8 | bigint | | false | true | | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| c9 | bigint | | false | true | -1 | BIT_SHUFFLE | DEFAULT_COMPRESSION | 0 |
+------+--------+---------+-------------+----------+---------------+---------------+---------------------+------------+
