mikacur/MRS-operation-guide-lts
1
0
Fork 0
forked from docs/mapreduce-service
Code Pull Requests Activity
MRS-operation-guide-lts/doc/component-operation-guide/source/using_hudi/basic_operations/read/index.rst
proposalbot 3ccfbdc0f0 Changes to mrs_operation-guide from docs/doc-exports#475 (MRS component operatio 
Reviewed-by: Kacur, Michal <michal.kacur@t-systems.com>
Co-authored-by: proposalbot <proposalbot@otc-service.com>
Co-committed-by: proposalbot <proposalbot@otc-service.com>
2022-12-09 14:50:38 +00:00

2.9 KiB
Raw Blame History

original_name

mrs_01_24037.html

Read

The read operation of Hudi applies to three views of Hudi. You can select a proper view for query based on requirements.

Hudi supports multiple query engines, including Spark and Hive. For details, see Table 1 <mrs_01_24037__table42155834714> and Table 2 <mrs_01_24037__table8194141519510>.

Table 1 COW tables
Query Engine Real-time View/Read-optimized View Incremental View
Hive Y Y
Spark (SparkSQL) Y Y
Spark (SparkDataSource API) Y Y
Table 2 MOR tables
Query Engine Real-time View Incremental View Read-optimized View
Hive Y Y Y
Spark (SparkSQL) Y Y Y
Spark (SparkDataSource API) Y Y Y

Caution

  • Currently, the partition deduction capability is not supported when Hudi uses the Spark DataSource API to read data. For example, when the DataSource API is used to query a bootstrap table, the partition field may not be displayed or may be displayed as null.
  • For an incremental view, set hoodie.hudicow.consume.mode to INCREMENTAL. This parameter applies only to queries on the incremental view and cannot be used for queries on other types of Hudi tables or queries on other tables. You can set hoodie.hudicow.consume.mode to SNAPSHOT or any value to restore the configuration.
  • Reading COW Table Views <mrs_01_24098>
  • Reading MOR Table Views <mrs_01_24099>

reading_cow_table_views reading_mor_table_views