René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"JDBC driver: Closing a Connection does not close ResultSets originated from the DatabaseMetadata API, potentially leading to exceptions related to memory leaks","articleBody":"### Describe the bug, including details regarding any error messages, version, and platform.\n\nVery similar to https://github.com/apache/arrow-java/issues/932\n\nIf a `ResultSet` obtained via a method from the `DatabaseMetaData` JDBC interface is not closed at the time of closing the connection, an exception is thrown in `Connection.close()` This is separate from the linked bug, because the other one only contemplated `ResultSets` that originate in queries made via `Statements`. However, the behavior is very similar.\n\nCode to reproduce:\n\n```\n    try {\n\n      // Establish connection\n\n      Connection connection = DriverManager.getConnection(jdbcUrl, properties);\n\n      DatabaseMetaData metaData = connection.getMetaData();\n      // any other method that returns a ResultSet would also repro\n      ResultSet rs = metaData.getTableTypes();\n      // this eliminates the exception\n      // rs.close(); \n\n      connection.close();\n\n    } catch (Exception e) {\n      System.err.println(\"Error: \" + e.getMessage());\n      e.printStackTrace();\n    }\n\n```\n\nResulting in the following exception (under version 18.3.0)\n\n\n```\nJan 27, 2026 2:02:59 AM org.apache.arrow.driver.jdbc.shaded.org.apache.arrow.memory.BaseAllocator close\nSEVERE: Memory was leaked by query. Memory leaked: (64)\nAllocator(VectorSchemaRootTransformer) 0/64/64/9223372036854775807 (res/actual/peak/limit)\n\nError: Exception while closing: Memory was leaked by query. Memory leaked: (64)\nAllocator(VectorSchemaRootTransformer) 0/64/64/9223372036854775807 (res/actual/peak/limit)\n\njava.sql.SQLException: Exception while closing: Memory was leaked by query. Memory leaked: (64)\nAllocator(VectorSchemaRootTransformer) 0/64/64/9223372036854775807 (res/actual/peak/limit)\n\n\tat org.apache.arrow.driver.jdbc.shaded.org.apache.calcite.avatica.Helper.createException(Helper.java:56)\n\tat org.apache.arrow.driver.jdbc.shaded.org.apache.calcite.avatica.Helper.createException(Helper.java:41)\n\tat org.apache.arrow.driver.jdbc.ArrowFlightConnection.close(ArrowFlightConnection.java:190)\n\tat MemoryLeakRepro.main(MemoryLeakRepro.java:136)\nCaused by: java.lang.RuntimeException: Exception while closing: Memory was leaked by query. Memory leaked: (64)\nAllocator(VectorSchemaRootTransformer) 0/64/64/9223372036854775807 (res/actual/peak/limit)\n\n\tat org.apache.arrow.driver.jdbc.shaded.org.apache.arrow.util.AutoCloseables.closeNoChecked(AutoCloseables.java:211)\n\tat java.base/java.lang.Iterable.forEach(Iterable.java:75)\n\tat org.apache.arrow.driver.jdbc.ArrowFlightConnection.close(ArrowFlightConnection.java:185)\n\t... 1 more\nCaused by: java.lang.IllegalStateException: Memory was leaked by query. Memory leaked: (64)\nAllocator(VectorSchemaRootTransformer) 0/64/64/9223372036854775807 (res/actual/peak/limit)\n\n\tat org.apache.arrow.driver.jdbc.shaded.org.apache.arrow.memory.BaseAllocator.close(BaseAllocator.java:504)\n\tat org.apache.arrow.driver.jdbc.shaded.org.apache.arrow.util.AutoCloseables.closeNoChecked(AutoCloseables.java:209)\n\t... 3 more\n\n\n```\n","author":{"url":"https://github.com/ennuite","@type":"Person","name":"ennuite"},"datePublished":"2026-01-27T02:12:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/990/arrow-java/issues/990"}