09.05.2018 17:15, liviuslivius wrote:

> >> No, caching is left up to OS.
>
> i do not understand above. I have dissabled os caching in firebird.conf.
> Also file is created by Firebird not OS. Can you explain this more?

You've disabled file-level caching for the database file, but this
setting doesn't affect temporary files. While they're created by
Firebird, Windows is asked to aggressively cache them if possible:

Quoting MSDN:

"Specifying the FILE_ATTRIBUTE_TEMPORARY attribute causes file systems
to avoid writing data back to mass storage if sufficient cache memory is
available, because an application deletes a temporary file after a
handle is closed. In that case, the system can entirely avoid writing
the data. Although it does not directly control data caching in the same
way as the previously mentioned flags, the FILE_ATTRIBUTE_TEMPORARY
attribute does tell the system to hold as much as possible in the system
cache without writing and therefore may be of concern for certain
applications."

There's no such a hint on Linux though, the default file-caching policy
is used there. To ensure in-memory storage, TempDirectories may be tuned
to redirect writes to tmpfs, for example.


Dmitry