Kbase 19324: Deleting a database with the server running
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
10/12/1999 |
|
Title : Deleting a database with the server running
This document applies to: Progress Databases
Version and Release Number: All (on unix)
Summary:
This kbase will discuss a possible procedure for saving a database that has been accidentally deleted. This requires the database server to be up and clients to be connected. The recommended procedure is to restore from backup, but if that is not available, you may use this method to get your database back.
Step by step details:
It possible to delete the database files on disk while the database server is up. This can happen for a number of reasons, but it is all user error. If this happens, it is possible to save the information in the database.
When the server is running, and clients are connected, they have file descriptors to the disk files that contain the database. When a user deletes a file, the space that is used is not immediately available for re-use if there is still an open file descriptor for it. The database files are like the sort files that Progress creates: you cannot see them from a directory list, but they still take up disk space. Once the last file descriptors for these files are closed, the space used by these files is then made available for re-use.
If a backup is not available, one way to save the database at this stage is to immediately dump the data and definitions from it, using the clients that are currently connected. The processes that are still connected will still be able to read the data from the files. Once the last client process disconnects from the database, you will not be able to get any more information out of it.
NOTE: The recommended approach is to restore from backup. The method here should only be employed if restoring a backup is not feasible.
References To Written Documentation or Other KnowledgeBase Documents:
Progress Software Technical Support Note # 19324