[jira] [Created] (SPARK-40802) [SQL] Enhance JDBC Connector to use PreparedStatement.getMetaData() to resolve schema instead of PreparedStatement.executeQuery()

["Mingli Rui (Jira)" <ji...@apache.org>]

Mingli Rui created SPARK-40802:
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             Summary: [SQL] Enhance JDBC Connector to use PreparedStatement.getMetaData() to resolve schema instead of PreparedStatement.executeQuery()
                 Key: SPARK-40802
                 URL: https://issues.apache.org/jira/browse/SPARK-40802
             Project: Spark
          Issue Type: Improvement
          Components: SQL
    Affects Versions: 2.1.0
            Reporter: Mingli Rui


Currently, Spark JDBC Connector uses *PreparedStatement.executeQuery()* to resolve the JDBCRelation's schema. The schema query is like *s"SELECT * FROM $table_or_query WHERE 1=0".*

But it is not necessary to execute the query. It's enough to *prepare* the query. With preparing the statement, the query is parsed and compiled, but is not executed. It will be more efficient.

So, it's better to use PreparedStatement.getMetaData() to resolve schema.



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