Reading COW Table Views¶
Reading the real-time view (using Hive and SparkSQL as an example): Directly read the Hudi table stored in Hive.
select count(*) from test;
Reading the real-time view (using the Spark DataSource API as an example): This is similar to reading a common DataSource table.
QUERY_TYPE_OPT_KEY must be set to QUERY_TYPE_SNAPSHOT_OPT_VAL.
spark.read.format("hudi") .option(QUERY_TYPE_OPT_KEY, QUERY_TYPE_SNAPSHOT_OPT_VAL) // Set the query type to the real-time view. .load("/tmp/default/cow_bugx/*/*/*/*") // Set the path of the Hudi table to be read. The current table has three levels of partitions. .createTempView("mycall") spark.sql("select * from mycall").show(100)
Reading the incremental view (using Hive and SparkSQL as an example):
set hoodie.test.consume.mode=INCREMENTAL; // Specify the incremental reading mode. set hoodie.test.consume.max.commits=3; // Specify the maximum number of commits to be consumed. set hoodie.test.consume.start.timestamp=20201227153030; // Specify the initial incremental pull commit. select count(*) from default.test where `_hoodie_commit_time`>'20201227153030'; // This filtering condition must be added, and the value is the initial incremental pull commit.
Reading the incremental view (using the Spark DataSource API as an example):
QUERY_TYPE_OPT_KEY must be set to QUERY_TYPE_INCREMENTAL_OPT_VAL.
spark.read.format("hudi") .option(QUERY_TYPE_OPT_KEY, QUERY_TYPE_INCREMENTAL_OPT_VAL) // Set the query type to the incremental mode. .option(BEGIN_INSTANTTIME_OPT_KEY, "20210308212004") // Specify the initial incremental pull commit. .option(END_INSTANTTIME_OPT_KEY, "20210308212318") //: Specify the end commit of the incremental pull. .load("/tmp/default/cow_bugx/*/*/*/*") // Set the path of the Hudi table to be read. The current table has three levels of partitions. .createTempView("mycall") // Register as a Spark temporary table. spark.sql("select * from mycall where `_hoodie_commit_time`>'20210308211131'")// Start the query. The statement is the same as the Hive incremental query statement. .show(100, false)
Reading the read-optimized view: The read-optimized view of COW tables is equivalent to the real-time view.