Mark, I agree your explanation is highly logical. But, using the words that were told to me by another developer, the generators values he found are previous values (the last used values at the development db before the overwriting by the new copy) (may be this information is not 100% of confidence, if the generators are in the same file than the tables). I think, at least, they had to be of values changed during the copy process, or old values, if no change have been applied to some of them, ok ?
--- On Thu, 5/31/12, Mark Rotteveel <m...@lawinegevaar.nl> wrote: From: Mark Rotteveel <m...@lawinegevaar.nl> Subject: Re: RES: [firebird-support] Copy of the current db not updating generators To: firebird-support@yahoogroups.com Date: Thursday, May 31, 2012, 4:56 PM On Thu, 31 May 2012 14:29:41 +0200, Hannes Streicher <hstreic...@gmx.de> wrote: > Hello Tupy... nambá, > > what is the setting of forced writes > because generators are outside of transaction control and thf shud be > updated > immediately If your generators are at the start of the database file and the copying takes a while (large db), and there are a lot of concurrent transaction then the state of the generator page at the time that page was copied is not the same as at the time the last page of the database file is copied. Eg T=1 generator page copied, generatorX = 1 T=2 concurrent transaction changes generatorX = 2 . . . T=N last data page is copied, generatorX = 2 + x (where x >= 0) Now the copy of the database is in an inconsistent state as the generator page in the copy says the value = 1, while other parts of the file might have been written as part of the transaction that used the result of the generator having value 2. ------------------------------------ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Visit http://www.firebirdsql.org and click the Resources item on the main (top) menu. Try Knowledgebase and FAQ links ! Also search the knowledgebases at http://www.ibphoenix.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Yahoo! Groups Links [Non-text portions of this message have been removed]
