Find Duplicate Filenames in Oracle Database: Code Breakdown and Insights

This post dives into an Oracle Database code snippet that identifies duplicate filenames across your entire database. We'll break down the code, explain its purpose, and provide valuable insights for optimizing your database management.

Find duplicate filenames. Searches for files with the same name in all directories.

Sample SQL Command

1select 	count(substr(name, instr(name, '/', -1) + 1, 999)) "total"
2,	count(distinct substr(name, instr(name, '/', -1) + 1, 999)) "distinct" 
3from 	v$datafile
4/

Purpose:

The provided SQL code helps you locate files with identical names within the Oracle Database. This can be crucial for tasks like:

• Identifying unnecessary redundancy: Duplicate files consume storage space unnecessarily. This code helps pinpoint them for potential deletion or consolidation.
• Maintaining data integrity: Inconsistent filenames within a database can lead to data management issues. This code can be a starting point for ensuring filename consistency.

Code Breakdown:

Let's dissect the code line by line:

• select: This keyword initiates the selection of data from the database.
• count(substr(name, instr(name, '/', -1) + 1, 999)) "total": This calculates the total number of filenames present in the v$datafile view.
  • substr(name, instr(name, '/', -1) + 1, 999): This function extracts the filename from the full path stored in the name column. It starts after the last occurrence of / (forward slash) and retrieves a maximum of 999 characters.
  • count(): This function counts the number of occurrences based on the provided expression.
  • "total": This renames the count result as "total" for better readability.
• , count(distinct substr(name, instr(name, '/', -1) + 1, 999)) "distinct": This calculates the number of distinct filenames (without duplicates).
  • distinct: This keyword ensures only unique entries are counted within the substr function.
  • "distinct": This renames the distinct count result as "distinct" for clarity.
• from v$datafile: This specifies the data source as the v$datafile view, which contains information about datafiles used by the database.
• /: This indicates the end of the SQL statement.

Key Points and Insights:

• This code offers a quick way to identify potential duplicate filenames within the database.
• The v$datafile view might not include all file types; consult your Oracle documentation for a comprehensive solution.
• The 999 limit in the substr function ensures most filenames are captured. However, adjust this value if your filenames are exceptionally long.
• This code provides a starting point. You can further refine it to filter specific file types or directories based on your needs.

Conclusion

By understanding this code and its insights, you can effectively manage duplicate filenames in your Oracle Database, optimizing storage usage and data consistency.

References:

Oracle documentation on v$datafile view: https://docs.oracle.com/en/database/oracle/oracle-database/23/refrn/V-DATAFILE.html

Substring function (substr) in Oracle SQL: https://docs.oracle.com/en/database/oracle/oracle-database/23/sqlrf/SUBSTR.html