Subject Re: [firebird-support] DatabaseGrowthIncrement & embedded database
Author Helen Borrie
At 07:02 AM 27/01/2009, you wrote:
>Just wondered if anyone knew if the parameter DatabaseGrowthIncrement
>is used by the embedded version of Firebird ?.

Yes. Embedded is just a deployment option, not a different database engine.

An enhancement introduced in v.2.1 for page allocation (i.e., requesting and securing blocks of disks from the file system) provides a "safety window" for when a "disk full" situation is at hand. As a positive side effect it should tend to reduce disk fragmentation over time.

The purpose of this parameter is to enable you to adjust the size of that safety window.

>I've added it to my firebird.conf file but I cant really tell if it makes a difference or
>not. I'm using Firebird 2.1.x

What is the "difference" you were expecting?

You might have *altered* the default setting, but you didn't "add" anything.

Setting the parameter to something different from the default doesn't somehow defrag your disk! There's nothing Firebird can do to consolidate fragments. It still has to trust the file system to allocate contiguous blocks. So this enhancement won't be any help if the HDD is already so fragmented that there are no contiguous blocks available of the configured allocation size.

Even if you disable it entirely (by setting it to 0) Firebird will still work.