Subject Re: [firebird-support] "12. Don't forget to enable file cache with big Firebird cache page"
Author Alexey Kovyazin
Post date 2019-01-09T11:01:17Z
Hi Karol,

This advice is based on our experience - disabling file cache for big databases (definitely larger than RAM size) leads to slowness.
I don't have explanation for this on the theoretical level.

If you have real-world example when Firebird works faster without file cache, please provide details about it.

Regards,
Alexey Kovyazin
IBSurgeon





On 09.01.2019 10:57, liviuslivius liviuslivius@... [firebird-support] wrote:
 
Hi,
 
article "23 More Ways To Speed Up Firebird".
 
Can you explain me point "12. Don't forget to enable file cache with big Firebird cache page".
 
I can imagine difference only in 2 situations.
 
1. When all attachments are disconnected and connected again.
Then yes, Windows cache can be more than benefit here - but we can turn on linger to achive near the same.
 
2. Database is bigger than Firebird cache.
Than using also system cache can increase performance as there is a chance that Windows will cache some portion of database not cached by FB itself.
And Windows can decide then, if it neeed cache other files or some portion of DB.
 
Is there any benefit of enabling system cache if Firebird cache is set to bigger value than database itself?
I see oposite performance in such situation.
But difference is marginally from 0 to 5% difference - than i do not know if there is any difference or i see some other process involved.
 
Are there other situations when enabling system cache will benefit also?
 
regards,
Karol Bieniaszewski