Submit a DB Import Command¶
-
POST/api/v1.2/commands/¶
Import commands allows you to pull data from a relational database to QDS in a Hive table. You can either pull a
complete table or a subset of it and this can be done using mode 1. In mode 1, to selectively pull the rows, you can
specify the condition using the db\_where option. If only a subset of column must be pulled, then you can
specify a comma-separated list in the db\_columns option.
To speed up the process of pulling data, you can set db\_parallelism in which case, Qubole opens multiple connections
to the database to pull the data. In case of mode 1, Qubole automatically detects and uses primary key column of the table
to split the work. Bear in mind that setting a very high value for db\_parallelism adds pressure on the database.
Sophisticated users can specify a custom query to transform the data before pulling it using mode 2. In case of mode 2,
if db\_parallelism > 1, Qubole needs more input to split the work. So, you must specify:
- db_split_column: the column used to split the work
- db_boundary_query: the query used to get a range on the column typically it would be as the following example:
select min(db_split_column), max(db_split_column) from db_table - db_extract_query: must have a WHERE clause with $CONDITIONS in it.
At execution time, $CONDITIONS is replaced by clause like:
db_split_column > lower_val AND db_split_column <= upper_valThis is used to determine boundary for splitting work.
Required Role¶
The following users can make this API call:
- Users who belong to the system-admin or system-user group.
- Users who belong to a group associated with a role that allows submitting a command. See Managing Groups and Managing Roles for more information.
Simple Mode¶
Note
Parameters marked in bold below are mandatory. Others are optional and have default values.
| Parameter | Description |
|---|---|
| command_type | DbImportCommand |
| schema | It is the source database to import into. THe default schema is default. |
| hive_table | Specify Hive table to import into. |
| mode | 1 |
| dbtap_id | DbTap ID of the source database in Qubole. |
| db_table | Table to import from. |
| additional_options | You can use this parameter to add any additional parameters to the command that you
want to execute. For example, if you want to add column mapping to the command,
then add --map-column-hive id=int,data=string through additional_options. |
| db_columns | Use this option when you want only a subset of all columns. It can contain a list of a comma-separated columns. |
| hive_serde | Specify the serde type of the Hive table to import into. Supported values are avro,
orc, and parquet. By default, Hive table is assumed to be of TXT format. |
| part_spec | Denotes the partition specification for a Hive table. |
| retry | Denotes the number of retries for a job. Valid values of retry are 1, 2, and 3. |
| retry_delay | Denotes the time interval between the retries when a job fails. |
| db_where | where clause to be applied to the table before extracting rows to be imported |
| db_parallelism | Number of parallel threads to use for extracting data. |
| name | Add a name to the command that is useful while filtering commands from the command history. It does not accept & (ampersand), < (lesser than), > (greater than), ” (double quotes), and ‘ (single quote) special characters, and HTML tags as well. It can contain a maximum of 255 characters. |
| tags | Add a tag to a command so that it is easily identifiable and searchable from the
commands list in the Commands History. Add a tag as a filter value while searching
commands. It can contain a maximum of 255 characters.
A comma-separated list of tags can be associated with a single command. While adding
a tag value, enclose it in square brackets. For example, {"tags":["<tag-value>"]}. |
| use_customer_cluster | To run the query on a specific Hadoop 2 cluster, set this option to true. |
| customer_cluster_label | The label of the Hadoop 2 cluster on which you want to run the command. It becomes
mandatory when use_customer_cluster is set to true. |
| macros | Denotes the macros that are valid assignment statements containing the variables and
its expression as: macros: [{"<variable>":<variable-expression>}, {..}]. You can
add more than one variable. For more information, see Macros. |
| timeout | It is a timeout for command execution that you can set in seconds. Its default value is 129600 seconds (36 hours). QDS checks the timeout for a command every 60 seconds. If the timeout is set for 80 seconds, the command gets killed in the next minute that is after 120 seconds. By setting this parameter, you can avoid the command from running for 36 hours. |
Examples¶
Running a Data Import Command in the Simple Mode¶
curl -i -X POST -H "X-AUTH-TOKEN: $AUTH_TOKEN" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"command_type": "DbImportCommand", "mode":"1", "hive_table":"sqltest", "dbtap_id":"2", "db_table": "data",
"db_where":"id < 10", "db_parallelism":2, "db_columns":"col_1,col_2"}' \ 'https://gcp.qubole.com/api/v1.2/commands'
Running a Data Import Command on an Hadoop 2 Cluster¶
curl -i -X POST -H "X-AUTH-TOKEN: $AUTH_TOKEN" -H "Content-Type: application/json" -H "Accept: application/json" \
-d { "command_type": "DbImportCommand", "mode":"1", "hive_table": "test", "dbtap_id":"286",
"db_table" : "test-table", "db_parallelism":1, "db_columns": "a",
"use_customer_cluster" : "true", "customer_cluster_label":"hadoop2"
}
Advanced Mode¶
Required Role¶
The following users can make this API call:
- Users who belong to the system-admin or system-user group.
- Users who belong to a group associated with a role that allows submitting a command. See Managing Groups and Managing Roles for more information.
Note
Parameters marked in bold below are mandatory. Others are optional and have default values.
| Parameter | Description |
|---|---|
| command_type | DbImportCommand |
| schema | It is the source database to import into. THe default schema is default. |
| hive_table | Specify Hive table to import into |
| mode | 2 |
| dbtap_id | DbTap ID of the source database in Qubole |
| db_extract_query | SQL query to be applied at the source database for extracting data. $CONDITIONS must be part of the where clause. |
| db_columns | Use this option when you want only a subset of all columns. It can contain a list of a comma-separated columns. |
| db_boundary_query | Query to be used get range of row IDs to be extracted |
| db_split_column | Column used as row ID to split data into ranges |
| db_parallelism | Number of parallel threads to use for extracting data |
| hive_serde | Specify the serde type of the Hive table to import into. Supported values are avro, orc, and parquet.
By default, Hive table is assumed to be of TXT format. |
| additional_options | You can use this parameter to add any additional parameters to the command that you want to execute. For example,
if you want to add column mapping to the command, then add --map-column-hive id=int,data=string through
additional_options. |
| use_customer_cluster | To run the query on a specific Hadoop 2 cluster, set this option to true. |
| customer_cluster_label | The label of the Hadoop 2 cluster on which you want to run the command. It becomes mandatory when
use_customer_cluster is set to true. |
| name | Add a name to the command that is useful while filtering commands from the command history. It does not accept & (ampersand), < (lesser than), > (greater than), ” (double quotes), and ‘ (single quote) special characters, and HTML tags as well. It can contain a maximum of 255 characters. |
| tags | Add a tag to a command so that it is easily identifiable and searchable from the commands list in the
Commands History. Add a tag as a filter value while searching commands. It can contain a maximum of 255
characters. A comma-separated list of tags can be associated with a single command. While adding a tag value,
enclose it in square brackets. For example, {"tags":["<tag-value>"]}. |
| macros | Denotes the macros that are valid assignment statements containing the variables and its expression as:
macros: [{"<variable>":<variable-expression>}, {..}]. You can add more than one variable.
For more information, see Macros. |
| timeout | It is a timeout for command execution that you can set in seconds. Its default value is 129600 seconds (36 hours). QDS checks the timeout for a command every 60 seconds. If the timeout is set for 80 seconds, the command gets killed in the next minute that is after 120 seconds. By setting this parameter, you can avoid the command from running for 36 hours. |
Examples¶
Example 1¶
curl -i -X POST -H "X-AUTH-TOKEN: $AUTH_TOKEN" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"command_type": "DbImportCommand", "mode":"2", "hive_table":"HiveData", "dbtap_id":"2",
"db_extract_query":"select id, dt from mydata where $CONDITIONS and id < 10",
"db_boundary_query":"select min(id), max(id) from mydata", "db_split_column":"id", "db_parallelism":2,
"db_columns":"col_1,col_2"}' \ "https://gcp.qubole.com/api/v1.2/commands"
Example 2¶
curl -i -X POST -H "X-AUTH-TOKEN: <MYTOKEN>" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"command_type": "DbImportCommand", "mode":"2", "hive_table":"HiveTableImportData", "dbtap_id":"1924",
"db_extract_query":"select id, task_id, event, owner, extra, SUBSTRING(execution_date, 1, 10)
as dt1 from table2 WHERE $CONDITIONS", "part_spec": "dt=2017-01-01" ,"db_parallelism" : "1"}' \
"https://gcp.qubole.com/api/v1.2/commands"
Example 3¶
curl -i -X POST -H "X-AUTH-TOKEN: <MYTOKEN>" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"mode": "2", "hive_table": "HiveTableData", "dbtap_id": None, "db_parallelism": 2,
"db_extract_query" : "select * from table1 where $CONDITIONS",
"db_boundary_query" : "select min(id), max(id) from table1", "db_split_column" : "id"}' \
"https://gcp.qubole.com/api/v1.2/commands"
Example 4¶
curl -i -X POST -H "X-AUTH-TOKEN: <MYTOKEN>" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"mode": "2", "hive_table": "RecentHiveData", "dbtap_id": None, "db_parallelism": 2,
"db_extract_query" : "select * from table1 where $CONDITIONS",
"db_boundary_query" : "select min(id), max(id) from table1", "db_split_column" : "id"}' \
"https://gcp.qubole.com/api/v1.2/commands"
Example 5¶
curl -i -X POST -H "X-AUTH-TOKEN: <MYTOKEN>" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"mode": "2", "hive_table": "HiveAvroData", "dbtap_id": None, "db_parallelism": 2,
"db_extract_query" : "select * from table4 where $CONDITIONS",
"db_boundary_query" : "select min(id), max(id) from table4", "db_split_column" : "id",
"part_spec" : "dt=2013/country=india", "hive_serde": "avro"}' \ "https://gcp.qubole.com/api/v1.2/commands"
Example 6¶
curl -i -X POST -H "X-AUTH-TOKEN: <MYTOKEN>" -H "Content-Type: application/json" -H "Accept: application/json" \
-d '{"mode": "2", "hive_table": "HiveORCData", "dbtap_id": None, "db_parallelism": 1,
"db_extract_query" : "select id, data from table11 where $CONDITIONS",
"part_spec" : "dt=2013/country=us", "hive_serde": "orc" }' \ "https://gcp.qubole.com/api/v1.2/commands"