Subject | Re: [firebird-support] Firebird BLOB vs. File Name Storage |
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Author | Edward Flick |
Post date | 2004-03-30T22:30:26Z |
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Hey Ann,
Boy I am just full of questions aren't I. Well, this will probably be
the last couple.
|>With forced writes off (not that I plan on doing this as I'm using the
|>embedded server), it should still provide the same level of consistency,
|>correct?
|
| Nope. Not everything that's written is data. If your transaction
| inventory page (for one) dies in the file cache, the database is going to
| require major resuscitation.
So you are saying it is the unknown boundary at which the disk cache
pauses at that can cause inconsistencies, if the boundary happens to
stop in the middle of a critical page write? Do hard drives in general
have a mechanism to where it won't start writing to a new page if it
detects power failure, or what would keep this from happening with
forced writes on? Just the probability of such a small page write being
interrupted?
| The problem with backing up stable blobs is that you spend a lot of time
| (and space) creating new copies of exactly the same old stuff.
How tough would it be to modify gbak to support incremental backups? Is
the generation number (is this the correct term?) backed up with the
data? Thanks
Edward Flick
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Hey Ann,
Boy I am just full of questions aren't I. Well, this will probably be
the last couple.
|>With forced writes off (not that I plan on doing this as I'm using the
|>embedded server), it should still provide the same level of consistency,
|>correct?
|
| Nope. Not everything that's written is data. If your transaction
| inventory page (for one) dies in the file cache, the database is going to
| require major resuscitation.
So you are saying it is the unknown boundary at which the disk cache
pauses at that can cause inconsistencies, if the boundary happens to
stop in the middle of a critical page write? Do hard drives in general
have a mechanism to where it won't start writing to a new page if it
detects power failure, or what would keep this from happening with
forced writes on? Just the probability of such a small page write being
interrupted?
| The problem with backing up stable blobs is that you spend a lot of time
| (and space) creating new copies of exactly the same old stuff.
How tough would it be to modify gbak to support incremental backups? Is
the generation number (is this the correct term?) backed up with the
data? Thanks
Edward Flick
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