一、说明
·支持内核：Presto、SparkSQL。
·支持表类型：原生表、外部表。
·用途：展示执行 sql 的逻辑或物理计划。
二、SparkSQL
EXPLAIN [ EXTENDED | CODEGEN | COST | FORMATTED ] statementEXPLAIN ANALYZEEXPLAIN ANALYZE [VERBOSE] statement
三、示例
— prestoEXPLAIN (TYPE VALIDATE) SELECT regionkey, count(*) FROM nation GROUP BY 1;EXPLAIN (TYPE IO, FORMAT JSON) INSERT INTO test_nation SELECT * FROM nation WHERE regionkey = 2;– EXPLAIN ANALYZEEXPLAIN ANALYZE SELECT count(*), clerk FROM orders WHERE orderdate > date '1995-01-01' GROUP BY clerk;EXPLAIN ANALYZE VERBOSE SELECT count(clerk) OVER() FROM orders WHERE orderdate > date '1995-01-01';