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https://issues.apache.org/jira/browse/SPARK-32992?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17202858#comment-17202858
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Apache Spark commented on SPARK-32992:
--------------------------------------
User 'MaxGekk' has created a pull request for this issue:
https://github.com/apache/spark/pull/29884
> In OracleDialect, "RowID" SQL type should be converted into "String" Catalyst
> type
> ----------------------------------------------------------------------------------
>
> Key: SPARK-32992
> URL: https://issues.apache.org/jira/browse/SPARK-32992
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.4.7, 3.1.0
> Reporter: Peng Cheng
> Priority: Minor
> Labels: jdbc, jdbc_connector
>
> Most JDBC drivers use long SQL type for dataset row ID:
>
> (in org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils)
> {code:java}
> private def getCatalystType(
> sqlType: Int,
> precision: Int,
> scale: Int,
> signed: Boolean): DataType = {
> val answer = sqlType match {
> // scalastyle:off
> ...
> case java.sql.Types.ROWID => LongType
> ...
> case _ =>
> throw new SQLException("Unrecognized SQL type " + sqlType)
> // scalastyle:on
> }
> if (answer == null)
> { throw new SQLException("Unsupported type " +
> JDBCType.valueOf(sqlType).getName) }
> answer
> {code}
>
> Oracle JDBC drivers (of all versions) are rare exception, only String value
> can be extracted:
>
> (in oracle.jdbc.driver.RowidAccessor, decompiled bytecode)
> {code:java}
> ...
> String getString(int var1) throws SQLException
> { return this.isNull(var1) ? null :
> this.rowData.getString(this.getOffset(var1), this.getLength(var1),
> this.statement.connection.conversion.getCharacterSet((short)1)); }
> Object getObject(int var1) throws SQLException
> { return this.getROWID(var1); }
> ...
> {code}
>
> This caused an exception to be thrown when importing datasets from an Oracle
> DB, as reported in
> [https://stackoverflow.com/questions/52244492/spark-jdbc-dataframereader-fails-to-read-oracle-table-with-datatype-as-rowid:]
> {code:java}
>
> {{18/09/08 11:38:17 WARN scheduler.TaskSetManager: Lost task 0.0 in stage
> 5.0 (TID 23, gbrdsr000002985.intranet.barcapint.com, executor 21):
> java.sql.SQLException: Invalid column type: getLong not implemented for class
> oracle.jdbc.driver.T4CRowidAccessor at
> oracle.jdbc.driver.GeneratedAccessor.getLong(GeneratedAccessor.java:440)
> at oracle.jdbc.driver.GeneratedStatement.getLong(GeneratedStatement.java:228)
> at
> oracle.jdbc.driver.GeneratedScrollableResultSet.getLong(GeneratedScrollableResultSet.java:620)
> at
> org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$org$apache$spark$sql$execution$datasources$jdbc$JdbcUtils$$makeGetter$8.apply(JdbcUtils.scala:365)
> at
> org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$org$apache$spark$sql$execution$datasources$jdbc$JdbcUtils$$makeGetter$8.apply(JdbcUtils.scala:364)}}
>
> {code}
>
> Therefore, the default SQL type => Catalyst type conversion rule should be
> overriden in OracleDialect. Specifically, the following rule should be added:
> {code:java}
> case Types.ROWID => Some(StringType)
> {code}
>
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