Subject Re: [firebird-support] Firebird 3 - Auto Garbage collection with Sweep interval = 0
Author Norman Dunbar
Evening Arnaldo,

On 15/02/18 13:19, Arnaldo Caliari arnaldo.caliari@...
[firebird-support] wrote:
> Hi guys,
> maybe i have always misunderstood the garbage collection mechanism, the
> sweep interval, etc.. and i'm realising only now, but:

Welcome to my world! ;-)

> I have this database (Firebird 3.03 SuperServer x64)
>     Sweep interval:        0
> ...

> My question is : why garbage collection mechanism starts automatically
> when i browse these tables, despite the fact that i have Sweep Interval
> = 0 ? What is the point that i'm missing ?

Sweep interval is for an automatic sweep which gets carried out when the
Oldest snapshot transaction (OST) - Oldest Interesting Transaction (OIT)
exceeds a non-zero setting for the sweep interval. In the header
information, this is Oldest Snapshot minus Oldest Transaction.

Setting sweep interval to zero disables this automatic sweep. However,
are you aware that when a transaction visits a table, it clears out
'garbage' left behind by other previous transactions?

Also, when you backup the database, your garbage is/can be collected too.



Norman Dunbar
Dunbar IT Consultants Ltd

Registered address:
27a Lidget Hill
West Yorkshire
United Kingdom
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Company Number: 05132767