TL;不允许EXTERNAL
带 no的DR。LOCATION
最终答案在 Spark SQL 的语法定义文件SqlBase.g4中。
您可以找到CREATE EXTERNAL TABLE
as createTableHeader的定义:
CREATE TEMPORARY? EXTERNAL? TABLE (IF NOT EXISTS)? tableIdentifier
此定义用于支持的 SQL语句。
除非我记错了locationSpec
是可选的。这是根据 ANTLR 语法。代码可能会做出其他决定,而且看起来确实如此。
scala> spark.version
res4: String = 2.3.0-SNAPSHOT
val q = "CREATE EXTERNAL TABLE IF NOT EXISTS new_table (id BIGINT, StartTime TIMESTAMP, EndTime TIMESTAMP) PARTITIONED BY (year INT, month INT, day INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'"
scala> sql(q)
org.apache.spark.sql.catalyst.parser.ParseException:
Operation not allowed: CREATE EXTERNAL TABLE must be accompanied by LOCATION(line 1, pos 0)
== SQL ==
CREATE EXTERNAL TABLE IF NOT EXISTS new_table (id BIGINT, StartTime TIMESTAMP, EndTime TIMESTAMP) PARTITIONED BY (year INT, month INT, day INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY ' '
^^^
at org.apache.spark.sql.catalyst.parser.ParserUtils$.operationNotAllowed(ParserUtils.scala:39)
at org.apache.spark.sql.execution.SparkSqlAstBuilder$$anonfun$visitCreateHiveTable$1.apply(SparkSqlParser.scala:1096)
at org.apache.spark.sql.execution.SparkSqlAstBuilder$$anonfun$visitCreateHiveTable$1.apply(SparkSqlParser.scala:1064)
at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:99)
at org.apache.spark.sql.execution.SparkSqlAstBuilder.visitCreateHiveTable(SparkSqlParser.scala:1064)
at org.apache.spark.sql.execution.SparkSqlAstBuilder.visitCreateHiveTable(SparkSqlParser.scala:55)
at org.apache.spark.sql.catalyst.parser.SqlBaseParser$CreateHiveTableContext.accept(SqlBaseParser.java:1124)
at org.antlr.v4.runtime.tree.AbstractParseTreeVisitor.visit(AbstractParseTreeVisitor.java:42)
at org.apache.spark.sql.catalyst.parser.AstBuilder$$anonfun$visitSingleStatement$1.apply(AstBuilder.scala:71)
at org.apache.spark.sql.catalyst.parser.AstBuilder$$anonfun$visitSingleStatement$1.apply(AstBuilder.scala:71)
at org.apache.spark.sql.catalyst.parser.ParserUtils$.withOrigin(ParserUtils.scala:99)
at org.apache.spark.sql.catalyst.parser.AstBuilder.visitSingleStatement(AstBuilder.scala:70)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser$$anonfun$parsePlan$1.apply(ParseDriver.scala:69)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser$$anonfun$parsePlan$1.apply(ParseDriver.scala:68)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:97)
at org.apache.spark.sql.execution.SparkSqlParser.parse(SparkSqlParser.scala:48)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parsePlan(ParseDriver.scala:68)
at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:623)
... 48 elided
默认SparkSqlParser
(带有astBuilder
as SparkSqlAstBuilder
)具有以下导致异常的断言:
if (external && location.isEmpty) {
operationNotAllowed("CREATE EXTERNAL TABLE must be accompanied by LOCATION", ctx)
如果您认为应该允许此案例,我会考虑在Spark 的 JIRA中报告问题。请参阅SPARK-2825以获得支持的有力论据:
据我所知,CREATE EXTERNAL TABLE 已经可以工作,并且应该具有与 Hive 相同的语义。