Deciphering the "SQL0913 Row or object table in Schema type *FILE in use" Error in IBM iSeries (DB2)
This article delves into the "SQL0913 Row or object table in Schema type *FILE in use" error, a common issue when working with IBM iSeries (DB2) and Spring Data JPA. We'll explore the root cause, dissect a practical example, and provide a solution to overcome this hurdle.
Understanding the Error
The SQL0913 error signals that a table or object in your IBM iSeries database is currently locked for use. This means another process is actively working with the data in that table, preventing your current transaction from modifying it.
This is often encountered when performing operations such as insert, update, or delete on tables that are being accessed by other processes. The locking mechanism ensures data integrity, but it can also lead to these error scenarios.
Analyzing the Code Snippet
The code snippet you provided reveals an attempt to insert multiple records into the OSYTXL table using Spring Data JPA. You're iterating through data, constructing Osytxl entities, and then attempting to persist them using osytxlRepository.save(osytxlList). The save() method, while convenient, potentially creates a contention point.
Why the Error Occurs
The primary culprit is likely the save() method's behavior with respect to locking. When you call save(), Spring Data JPA typically tries to acquire a lock on the entire OSYTXL table to ensure consistency during the insertion process. If another process (perhaps a program or user) is already accessing the OSYTXL table, your transaction might be blocked, leading to the SQL0913 error.
Important Note: The *FILE schema type on IBM iSeries typically indicates physical files, which can be subject to stricter locking rules.
Resolution Strategies
Here are a few strategies to address the SQL0913 error:
-
Transaction Management: Examine your code for any other processes that could be accessing the
OSYTXLtable concurrently. Use transaction management techniques to isolate these operations, potentially using separate transactions or ensuring exclusive access. -
Optimistic Locking: Implement optimistic locking in your entity (
Osytxl) to handle concurrent access. This technique involves adding a version field to your entity and verifying that the version hasn't changed before persisting changes. -
Data Partitioning: If possible, consider dividing your data into smaller tables or partitions to reduce the scope of the locking issues.
-
Avoid Excessive Locking: Review your code for unnecessary locking mechanisms. Are there portions of your application that could be optimized to reduce the duration or frequency of locking?
-
Database Configuration: Investigate the database configuration settings related to locking. Perhaps there are settings that can be adjusted to improve concurrency and minimize locking conflicts.
Addressing the Code Snippet
Here's a revised approach that addresses some potential issues in the code snippet:
@Transactional(isolation = Isolation.SERIALIZABLE)
public void saveData(Osytxh osytxh, String[] lines) {
Collection<Osytxl> osytxlList = new ArrayList<>();
for (int lineNo = 0; lineNo < lines.length; lineNo++) {
Osytxl osytxl = new Osytxl();
osytxl.setTlcono(osytxh.getThcono());
osytxl.setTldivi(osytxh.getThdivi());
osytxl.setTltxid(osytxh.getThtxid());
osytxl.setTltxvr(osytxh.getThtxvr());
osytxl.setTllncd(osytxh.getThlncd());
osytxl.setTllmts(new BigDecimal("1437651510403"));
osytxl.setTllino(new BigDecimal(lineNo + 1));
osytxl.setTltx60(lines[lineNo]);
osytxlList.add(osytxl);
}
if (osytxlList.size() > 0) {
osytxlRepository.saveAll(osytxlList);
}
}
-
Transactional Annotation: The
@Transactionalannotation withIsolation.SERIALIZABLEensures that all data access operations within the method are executed within a single transaction. This minimizes locking conflicts. -
saveAll() Method: The
saveAll()method allows you to insert multiple entities in a single operation, potentially reducing the chance of locking errors.
Remember: This is just a starting point. Depending on the specifics of your application, other adjustments may be required.
Conclusion
The "SQL0913 Row or object table in Schema type *FILE in use" error is a sign of contention in your database environment. By understanding the root cause and applying the right strategies, you can avoid these errors and ensure the smooth operation of your applications.
This article provides a guide to tackling this common IBM iSeries challenge. Remember to carefully analyze your application and database settings to implement the most appropriate solution for your unique situation.
