But again how? The backup completion is affected by file size and whether said database is local or on a remote location. So originally, we perform guesstimates of how long it normally takes but that is not good enough. And we definitely cannot use:
As depending on your RAM and free memory, a diskwrite for the backup may happen several times gradually increasing its size; and when the first HDD write happens, your app with the approach above will deem it already complete.
This morning, an idea suddenly hit me and so I tried this trick now and it is working good, so I am sharing the trick here now.
For a backup progress and its possible completion to be determined, we have to at least know how much MB the backup will consume. So here is how:
1. Check your archive folder and get all the backup files there via ADIR().
2. Get the latest backup via checking its date and time stamps
3. Get the filesize of that latest backup.
Now, we have a basis of a possible size of the next backup. Either it will be of the same size but most probably it will be a bit bigger. And that will be your basis for your progress bar indicator as well as possible completion. I have a timer on my main form which checks the users that remain online every 5 seconds so I put this there too:
If gomyapp.isbackup = 1
* Check if previous max backup bytes is not zero
If Thisform._bytes > 0
* Compare new size written vs last backup size
Set Compatible On
Local lnWidth, lnSize
lnSize = Fsize(gomyapp.archive)
lnWidth = Int((m.lnSize/Thisform._bytes)*133)
Thisform.coBackup.shpProgress.Width = m.lnWidth
If m.lnWidth >= 133
Thisform.coBackup.Visible = .F.
gomyapp.isbackup = 0
Endif
Set Compatible Off
Else
* 6 minutes
Thisform.coBackup.shpProgress.Width = Int((Thisform._backctr/360)*133)
If m.lnWidth >= 133
Thisform.coBackup.Visible = .F.
gomyapp.isbackup = 0
Endif
Endif
Endif
Thisform._bytes holds the bytes of the latest backup file. That is what I use now for comparison with the new backup as bytes are written down to the file in batches. So it is slowly getting bigger, and with it the progress bar is increasing too.
Now if you notice, I took the possibility that Thisform._bytes will have zero value. That will happen if there is no backup file yet; meaning they will perform the very first backup process. In that case I have that ELSE which is geared for 6 minutes, just to ensure it will be completed. You can increase or decrease the number of minutes by doing an initial backup test, check how long the backup took to complete and use the number of minutes on the above instead of that 360 value. I did the 6 minutes because our server is on the cloud and the speed of completion is dependent on the connection speed plus the size of the database. Truth is it is just taking a few minutes on my end for a 126MB backup file but I am just playing safe on that initial backup run. After that, the system will no longer switch onto that as there are now files for comparison.
So there it is. A way to give a user a good estimate of a backup completion. HTH!
