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Messages 1 to 8 of 8 total |
Backup while live? |
Tue, Oct 17 2006 6:29 AM | Permanent Link |
Am I right in thinking that the backup mechanism will operate happily
while the database is in use by other threads? They'll be reading and writing, but currently no transactions. Are there any conditions to the backup? Also, is it a pure copy of the table, or is it sort of "optimized"? That is, if I have a load of deleted blobs, do the deleted parts get copied too so that the database on restore would be exactly as original, or would it effectively be optimized by having old records deleted. I ask all this as I'd like a copy of a 24/7 database which has grown to 1.3Gb (blob file) and I want to see what is in it. If I restore and it is just 0.3Gb, then it wouldn't be the same of course. I guess I could have my control thread close everything down and then copy the files raw... /Matthew Jones/ | |
Tue, Oct 17 2006 7:00 AM | Permanent Link |
Roy Lambert NLH Associates Team Elevate | Matthew
I think that backing up will put a lock on the tables so that no inserts/edits can be done. Roy Lambert |
Tue, Oct 17 2006 7:59 AM | Permanent Link |
Hmm, do they just spin until the backup completes? Or will they fail?
Spinning would be fine. /Matthew Jones/ | |
Tue, Oct 17 2006 8:14 AM | Permanent Link |
Roy Lambert NLH Associates Team Elevate | Matthew
I thought I'd test my thinking and whilst running a backup from one app I was able to insert and edit data using DBSys. On that basis over to the guru <vbg> Roy Lambert |
Tue, Oct 17 2006 9:45 AM | Permanent Link |
"Jose Eduardo Helminsky" | Matthew
I don´t know what kind of data you will backup. But, is is *NOT* a simple file copy. Remember there are some relationships between files (tables) and imagine the situation you hold a sum of detail records in the master, you copy the master and just after the copy finish, other user delete the detail records. Referencial Integrity will be broken. Unless you use a restricted transaction locking related tables and copy them to another area then unlock and do the same for another related tables. But, even when you are doing a backup, the data can be read with any problems. They only can´t be changed (add, update or delete). Eduardo |
Tue, Oct 17 2006 9:56 AM | Permanent Link |
> running a backup from one app
Oooh - I'd not even thought of doing it from another app. What a good idea - it could be a support only thing. Hmm. Command line driven even for remote control and the "screen" user wouldn't even know... /Matthew Jones/ | |
Tue, Oct 17 2006 4:20 PM | Permanent Link |
Tim Young [Elevate Software] Elevate Software, Inc. timyoung@elevatesoft.com | Matthew,
<< Hmm, do they just spin until the backup completes? Or will they fail? Spinning would be fine. >> They spin, but if the backup takes a really long time they will eventually issue a lock error. Also, inserts and edits aren't blocked, only Posts or Deletes, i.e. other clients simply cannot write to the database while it's being backed up. They can, however, read from it and lock records. -- Tim Young Elevate Software www.elevatesoft.com |
Wed, Oct 18 2006 4:55 AM | Permanent Link |
Many thanks.
/Matthew Jones/ |
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