|Subject||Re: [firebird-support] garbage collection points|
> I studied good article about FB on this themaYes
> http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_oit and from
> articles on IBSurgeon pages), but I have still some small questions
> about. I will be glad of anybody's help.
> 1. From header page info:
> Oldest transaction - known as Oldest Interesting Transaction (first
> transaction in other state then commited)
> Oldest active - Oldest transaction currently active
> Oldest snapshot - known as Oldest Active Transaction (transaction
> what was active when current Oldest active transaction was run)
> Am I understand header page info correctly ?
> 2. If an transaction is rollbacked, it will be changed to commit stateYes. But only sweep will change transaction's state and only after succefull
> later by sweep process. Before it happen, do other transaction suppose
> to clean its' garbage (garbage of rollbacked transaction) ?
> I suppose cooperation mode in garbage collection.
run. Actually, sweep not changed every rolled back (dead) transaction state in TIP,
it just advanced OIT value on header page. This is a difference between background
garbage collector and sweep.
> 3. Is garbage collection process (again suppose cooperation mode) onUPDATE and DELETE also must read record, so answer is - yes
> record trigered only by SELECT statement or it could be trigered aswell
> by UPDATE or DELETE statements ?
> 4. OIT and OAT transaction numbers on header page are updated only justYes.
> in time when transaction start and will find out, that OIT and OAT are
> not actual ? So this transaction pickup new values into her local
> variables and will try to actualize header page ?