On Jul 29, 2018, at 5:46 PM, John Baughman wrote: > In planning for upgrading a client fo v16 I noted that the datafile needed to > be compacted so included a compact in my upgrade plan. > > A few days before I was to do the upgrade my client replace the server’s hard > drive with an SSD. Ok, so when it came time to do the compact I noted that it > no longer told be that the datafile needed to be compacted. I ignored that > and proceeded to compact the datafile. As luck would have it the compact > failed due to orphaned blobs in one of the tables. > > In my research of how to fix this problem I ran across this statement in a > tech note on the subject from 2011 (http://kb.4d.com/assetid=76195)… > > Note: Solid State Disk (SSD) drives do not face this challenge, so > there is actually no need to compact the data file on an SSD. In fact we > recommend NOT compacting the data file on an SSD because it contributes to > drive wear. For more information see Technical Note 10-09, SSDs and 4D v11 > SQL. > > Interesting! So I won’t try the compact again, but should I be worried about > the orphaned blobs? I think not, the database is working fine. Fixing the > orphans per the tech note involves compacting the address table for the table > in question. If I don’t need to do that I don’t particularly want to go down > that road.
That is interesting. But I think I would still compact occasionally, particularly if you do a mass deletion of records. It reduces the size of the data file, and that makes duplicating the data file faster. Orphaned blobs are not serious. They are due to a bug in 4D. It’s not really corruption. It’s just some blobs — the ones attached to blob fields that you have set to store the blob outside the record but in the data file — are hanging around in the data file and they are not attached to any records. They are like crumbs laying on the floor. If you don’t mind a little dirt on the floor no big deal. If you like a clean floor, then you want to remove those unused and unneeded orphan blobs. I certainly hope 4D has fixed the bug that caused these orphan blobs to appear. Tim ***************************************** Tim Nevels Innovative Solutions 785-749-3444 [email protected] ***************************************** ********************************************************************** 4D Internet Users Group (4D iNUG) Archive: http://lists.4d.com/archives.html Options: https://lists.4d.com/mailman/options/4d_tech Unsub: mailto:[email protected] **********************************************************************
