Eduardo Morras wrote:
At 09:34 01/12/2006, you wrote:
Hi there,
we are on an challanging project with very high requirements on
performance.
When doing some debugging we discover, that the sqlite method for
creating
an memory-based database is much slower than using e.g /dev/shm on
linux or
/tempfs on solaris. (We have measured an 20min performance advantage
for the
/dev/shm style on a batch run which takes 70min with :memory: and just
49min
using /dev/shm.
Because our project needs to be ported to windows - the /dev/shm is
not an
option - because win2000 does not support any temporary memory based file
system. But beside that, we guess, that there will be a possiblity to
tune
:memory: or we belief, that we to something wrong when using :memory:
(for
example pragma page_size ...).
Is there any body who can give us some advises to tune up our :memory:
database to become as fast as the /dev/shm alternativ?
Thanks
roland
On our project we desisted to use :memory: databases, only a ram disk
file system. From time to time make a snapshot to hard disk or other
persistent medium.
In windows i suppouse you can make a ram disk using malloc and copy
there your database file, set the pragma for temporary files to memory
and disable journaling. Make a new io routines access based on windows,
open/close, write/read etc... for access your memory malloc ram disk.
Again, from time to time stop reads/writes to database and save it to disk.
HTH
You might find you can get the same performance in a simpler way by just
disabling synchronous writes. Read Dr Hipp's explanation of a memory
database for the reason.
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