Help Center/ GaussDB(DWS)/ Developer Guide/ 8.3.0.x/ SQL on Hudi/ Querying a Hudi Foreign Table
Updated on 2024-04-30 GMT+08:00
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Querying a Hudi Foreign Table

You can query data in a Hudi foreign table. By default, it gives you a real-time view. You can set parameters to query the incremental data.

Querying Incremental Data

You can set incremental query parameters to implement incremental query.

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SET hoodie.SCHEMA.FOREIGN_TABLE.consume.mode=incremental;
SET hoodie.SCHEMA.FOREIGN_TABLE.consume.start.timestamp=start_timestamp;
SET hoodie.SCHEMA.FOREIGN_TABLE.consume.ending.timestamp=end_timestamp;
SELECT * FROM SCHEMA.FOREIGN_TABLE;

Example:

Query the incremental data of the MOR hudi foreign table public.rtd_mfdt_int_currency_ft from 20221207164617 to 20221207170234. Where:

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SET hoodie.public.rtd_mfdt_int_currency_ft.consume.mode=incremental;
SET hoodie.public.rtd_mfdt_int_currency_ft.consume.start.timestamp=20221207164617;
SET hoodie.public.rtd_mfdt_int_currency_ft.consume.ending.timestamp=20221207170234;
SELECT * FROM public.rtd_mfdt_int_currency_ft where _hoodie_commit_time>20221207164617 and _hoodie_commit_time<=20221207170234;

Querying the Configured Incremental Parameters

You can use the following function to check the incremental parameter configuration. 
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SELECT * FROM pg_show_custom_settings();

Querying the Properties of a Hudi Foreign Table (hoodie.properties)

Run the following command to query the hoodie.properties of the Hudi data on OBS: 
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SELECT * FROM hudi_get_options('SCHEMA.FOREIGN_TABLE');

Example: Query the hudi properties of the OBS foreign table rtd_mfdt_int_unit_ft in the current schema.

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SELECT * FROM hudi_get_options('rtd_mfdt_int_unit_ft');

Querying the Maximum Timeline of a Hudi Foreign Table

Run the following command to query the maximum timeline of the hudi data on OBS, that is, the latest submitted data:

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SELECT * FROM hudi_get_max_commit('SCHEMA.FOREIGN_TABLE');

Example: Query the maximum timeline of the OBS foreign table rtd_mfdt_int_unit_ft in the current schema.

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SELECT * FROM hudi_get_max_commit('rtd_mfdt_int_unit_ft');
Parent topic: SQL on Hudi