Subject Re: [firebird-support] Re: Merging two textual blob fields
Author Aage Johansen
>>Do you know the best way to step through each of 1.5 million records
>>without using up a massive ammount of resources? If I do a "SELECT *
>>FROM TABLE", then step through each record in turn, I'm going to run
>>into problems with memory (I think!).
> No, you won't. Sorting the records will use memory, but just reading
> and updating them shouldn't be a problem. It will create a significant
> undo log - you can avoid that but choosing a "no auto undo" transaction
> option if that's surfaced by your application. Firebird does not
> materialize the full set of records to be updated before updating them.
> Firebird does (must?) materialize all records before sorting them.

If it is done in an application he can do the insert or update in another
transaction, committing every few 100 or 1000 operations.

Stepping through 1.5 mill records may use resources on the client - choose
your components wisely.

Aage J.