>
> You could give the following settings a try:
>
> Page Size: 16K
> Page Buffers: 2048
> TempCacheLimit in firebird.conf: 134217728
> LockHashSlots in firebird.conf could be increased as well, e.g: 10009

Thank you, I give those settings a try. Firstly I need to back up/ restore the DB and it will take a lot of time. I will let know if thigs got better after settings change.

> Could be cooperative garbage collection with Classic as well. Is the
> large table frequently updated with larger batches?
>

Yes, everyday on the server it grows 100K records.