How did you test different page sizes. Did you recreate the database
over and over again?
I use |DB_CLOSE_DELAY=-1 because I want the database to be open when my
server is up
and closed when my server is down. I would assume not closing the database
during the times of inactivity keeps it responsive all the time, right?
|
Would increasing CACHE_SIZE=128000 ever make H2 slower?
Of course one needs to take care of JVM having enough of memory
allocated for it but other than that
the more you can keep in memory the faster, right?
I would really love a more in-depth documentation about H2's concurrency
and transactions.
I think that part was documented very well in HSQLDB. Other than that H2
seemed to me more
stable, less buggy, having more readable docs (HSQLDB's docs were messy
when trying to be formal)
and had better performance.
Maybe understanding better the practical differences of multithreaded
and mvcc in H2's implementation
would be easier to choose between them.
Now I only assume that MULTI_THREADED works well if you have a lot of
concurrent clients that do mostly reading.
- rami
On 17.6.2011 6:17, Dario Fassi wrote:
Hi,
This setting give me the best start point in my common use case:
PAGE_SIZE=4096
DB_CLOSE_DELAY=10
CACHE_SIZE=128000
MULTI_THREADED=1
just to share,
Dario
El 16/06/11 18:38, Rami Ojares escribió:
I set
PAGE_SIZE=8192
CACHE_SIZE=131056
WRITE_DELAY=10000
But did not see a considerable speedup with my database.
I do not use CLOBs or BLOBs so that might have been one reason.
Also I did not make any precise measurements but just wanted to share
my experience.
There might have been some speedup but I would say it was definately
less than 100%
I would have expected that setting the write delay that long would
have had a big impact.
The point being that what is most important would be to have clear
measurements on
what affects what. And it might be difficult to say what is the most
optimal page_size
or how much does the write delay affect performance in different
usage scenarios.
What I noticed though was that documentation says that PAGE_SIZE can
only be set
when creating the database. Further there is no way to see what the
actual PAGE_SIZE is.
At least it was not listed in the SETTINGS table.
In order to test this kind of feature it would be nice if one could
change it whenever needed
and more importantly somehow verify what it actually is.
- rami
On 16.6.2011 22:09, Nitin wrote:
Hi Thomas,
Is this (detect and set the best page size) coming in next release ?
may be as experiment or to gather feedback for more fine tuning ?
Regards,
Nitin
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