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Fix potential connection leak when using jdbc storage and Scan operation fails because the target table doesn't exist #2766

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Merged
merged 5 commits into from
Jun 17, 2025
+61 −0
Merged

Fix potential connection leak when using jdbc storage and Scan operation fails because the target table doesn't exist #2766

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4bb2e3a
Fix DB connection leak
komamitsu Jun 13, 2025
60d4fba
Only close connection when other exception occurs
komamitsu Jun 13, 2025
e96888e
Improve error handling based on feedback
komamitsu Jun 16, 2025
f18d40f
Take care of similar issue
komamitsu Jun 16, 2025
c96db72
Merge branch 'master' into close-scanner-conn-if-table-does-not-exist
feeblefakie Jun 17, 2025
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5 changes: 5 additions & 0 deletions core/src/main/java/com/scalar/db/storage/jdbc/JdbcDatabase.java
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Original file line number Diff line number Diff line change
Expand Up @@ -117,6 +117,11 @@ public Scanner scan(Scan scan) throws ExecutionException {
close(connection);
throw new ExecutionException(
CoreError.JDBC_ERROR_OCCURRED_IN_SELECTION.buildMessage(e.getMessage()), e);
} catch (Exception e) {
if (connection != null) {
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@brfrn169 brfrn169 Jun 16, 2025

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Don't we need to connection.rollback() here?

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@komamitsu komamitsu Jun 16, 2025

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Thanks! I focused on the connection leak, but I think the transaction should be rolled-back immediately to avoid potential future lazy-recovery. Addressed it in e96888e.

close(connection);
}
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@brfrn169 brfrn169 Jun 16, 2025

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The null handling is already done in the close() method, so we don't need to do that here:

Suggested change
if (connection != null) {
close(connection);
}
close(connection);

throw e;
}
}

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19 changes: 19 additions & 0 deletions core/src/test/java/com/scalar/db/storage/jdbc/JdbcDatabaseTest.java
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Expand Up @@ -138,6 +138,25 @@ public void whenScanOperationExecutedAndScannerClosed_shouldCallJdbcService() th
verify(connection).close();
}

@Test
public void
whenScanOperationExecutedAndJdbcServiceThrowsIllegalArgumentException_shouldCloseConnectionAndThrowIllegalArgumentException()
throws Exception {
// Arrange
Exception cause = new IllegalArgumentException("Table not found");
// Simulate the table not found scenario.
when(jdbcService.getScanner(any(), any())).thenThrow(cause);

// Act Assert
assertThatThrownBy(
() -> {
Scan scan = new Scan(new Key("p1", "val")).forNamespace(NAMESPACE).forTable(TABLE);
jdbcDatabase.scan(scan);
})
.isInstanceOf(IllegalArgumentException.class);
verify(connection).close();
}

@Test
public void
whenScanOperationExecutedAndScannerClosed_SQLExceptionThrownByConnectionCommit_shouldThrowIOException()
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