terrymanu commented on issue #33678:
URL:
https://github.com/apache/shardingsphere/issues/33678#issuecomment-3538797755
## Problem Overview:
ShardingSphere 5.4.1 throws "Order by value must implement Comparable."
exception when executing ORDER BY operations on TIMESTAMP WITH TIME ZONE type
fields in Oracle 12c environment.
## Root Causes:
1. Oracle Special Type Code Issue: Oracle JDBC driver uses type code -101
for TIMESTAMP WITH TIME ZONE, instead of the standard
java.sql.Types.TIMESTAMP_WITH_TIMEZONE (value 2014)
2. Missing Type Conversion Logic: In JDBCStreamQueryResult.java:104-120,
only standard TIMESTAMP type code 93 conversion is handled, but Oracle's
special -101 type code is not processed
3. Comparison Check Failure: In OrderByValue.java:110, because values with
-101 type code are not properly converted to java.sql.Timestamp, ordinary
Object objects are returned, which cannot implement the Comparable
interface
Problem Code Locations:
- OrderByValue.java:110 - Comparable interface check failure
- JDBCStreamQueryResult.java:104-106 - Missing handling for -101 type code
## Fix Suggestion
We need to add support for Oracle special type codes in the
JDBCStreamQueryResult.getValue() method. Here is the specific fix solution:
```java
// Add after line 104 in JDBCStreamQueryResult.java's getValue method
if (Timestamp.class == type) {
int columnType = resultSet.getMetaData().getColumnType(columnIndex);
// Handle Oracle TIMESTAMP WITH TIME ZONE special type code
if (columnType == 93 || columnType == -101 || columnType ==
Types.TIMESTAMP_WITH_TIMEZONE) {
return resultSet.getTimestamp(columnIndex);
}
}
```
## Testing Suggestions
After the fix, the following test cases need to be added:
1. Unit Tests: Add tests for Oracle TIMESTAMP WITH TIME ZONE type in
JDBCStreamQueryResultTest
2. Integration Tests: Create integration tests using Oracle database to
verify ORDER BY operations
3. Regression Tests: Ensure the fix does not affect normal functionality
of other database types
## Enthusiastic Invitation to Submit PR
We warmly welcome you to participate in the ShardingSphere community! If
you're willing to contribute code for this fix, this is a great opportunity to:
1. Deeply Understand ShardingSphere Kernel: By fixing this bug, you'll
learn about ShardingSphere's result set processing and type conversion
mechanisms
2. Contribute to Open Source Community: Your fix will help all developers
using Oracle TIMESTAMP WITH TIME ZONE
3. Enhance Technical Influence: As a ShardingSphere contributor, your name
will be recorded in the project's history
We Promise to Provide You:
- 🛠️ Technical Guidance: If you encounter any issues during development,
we'll provide detailed feedback in code reviews
- 📝 Documentation Support: Assist you in writing test cases and commit
messages that meet project standards
- 🤝 Community Recognition: Your contribution will be recognized and
appreciated by the community
Getting Started Steps:
1. Fork ShardingSphere repository
2. Create your feature branch based on dev branch
3. Implement the fix and write tests
4. Submit PR and describe your fix solution
Looking forward to your contribution! If you need any help, feel free to
contact us in GitHub issues or community channels. 🚀
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