PL/SQL UTL_FILE.FCLOSE_ALL

The UTL_FILE.FCLOSE_ALL procedure is part of Oracle’s PL/SQL UTL_FILE package, which provides file input/output (I/O) capabilities. This package allows PL/SQL code to read from and write to operating system files in a server’s filesystem, which is typically not directly accessible from PL/SQL.

The FCLOSE_ALL procedure specifically is used to close all open file handles that were opened during a PL/SQL session. It is useful for ensuring that all files that have been opened with UTL_FILE.FOPEN are properly closed, especially in cases where multiple files may be open or where an exception has occurred, and you need to close files to prevent resource leakage.

Key Points of UTL_FILE.FCLOSE_ALL

No Parameters: FCLOSE_ALL does not take any arguments. It acts on all currently open files in the session.

UTL_FILE.FCLOSE_ALL;

Usage Scenario

When you have opened multiple files using UTL_FILE.FOPEN and want to ensure all are closed.
In exception handling, where an error might prevent individual file handles from being closed properly. Using FCLOSE_ALL ensures that no open file handles remain after an error.

It helps prevent “file open” resource exhaustion by releasing all file resources in one call.

Automatic Closing of Files: It will close all open files, making it a useful cleanup method in procedures where you may have multiple file operations and want to ensure that resources are freed after use.

Behavior: If there are no files open, the procedure simply does nothing and completes successfully.

Example

Here’s a typical example of using UTL_FILE.FCLOSE_ALL in a PL/SQL block with exception handling:

DECLARE
  file_handle UTL_FILE.FILE_TYPE;
BEGIN
  -- Open a file for writing
  file_handle := UTL_FILE.FOPEN('TEMP_DIR', 'test_file.txt', 'W');
  
  -- Write some data to the file
  UTL_FILE.PUT_LINE(file_handle, 'Hello, World!');
  
  -- Close the file
  UTL_FILE.FCLOSE(file_handle);
  
EXCEPTION
  -- In case of an error, ensure all files are closed
  WHEN OTHERS THEN
    UTL_FILE.FCLOSE_ALL;
    RAISE;
END;

In this block:

A file is opened for writing using UTL_FILE.FOPEN.
The procedure attempts to write to the file and close it with UTL_FILE.FCLOSE.
If an error occurs, the UTL_FILE.FCLOSE_ALL procedure ensures that any remaining open files are closed, preventing file handle leaks.

Best Practices

Use UTL_FILE.FCLOSE_ALL in exception handling blocks, especially when multiple file operations are involved.

Avoid relying solely on it to close individual files if you know exactly which file handle should be closed. Use UTL_FILE.FCLOSE for that purpose.

Use it as a safeguard to prevent leaving any file open due to unexpected errors or incomplete file operations.

In summary, UTL_FILE.FCLOSE_ALL is a convenient procedure in PL/SQL for ensuring that all files opened using UTL_FILE are properly closed, thus preventing resource leaks and managing system resources efficiently.