Hello,
I have similar H2 1.4 MVCC performance problems with parallel selects.
In attached test case a test table is created with 10k records.
Then 4 threads are started, each executing 1000 consecutive selects, n-th
select returns n records.
If a test is started as is, with MULTI_THREADED=TRUE
I had a look through those traces but I did not seem any signs of a memory leak.
I've personally never tried to run H2 that hard, and Im sorry but I don't have time to track down this sort of problem
right now.
You are more than welcome to submit patches however :-)
--
You received this mes
In fact this test shows 3 problems:
1. Bad scalabity even with embedded server: H2 can't use more then 10% of
PU due to locking
2. Slow TCP exchange even with localhost
3. Degradation of TCP server performance, probably due to a leak
I would very appreciate your input for each of the problems
thanks.
looks like we are bottlenecking on the locking on the undoLog object in
TransactionStore, particularly in the commit() method.
I see a comment there
// TODO could synchronize on blocks (100 at a time or so)
which means perhaps Thomas had some ideas how this could be improved.
Bit late
Please see flight recordings taken from TCP:
1. after 30 mins run:
https://drive.google.com/file/d/0BzUtLq_vDgHWT3dadkk5ajBBZms/view?usp=sharing
2. after server restart:
https://drive.google.com/file/d/0BzUtLq_vDgHWWEd5SjJfT3pydXc/view?usp=sharing
On Sunday, December 11, 2016 at 5:37:41 PM
Sorry, that's not something I can analyze myself. I suggest you hook up a
profiler like visualvm and take CPU sampling profiles of both cases. Then
we could compare them to see what the problem is. Also take a heap dump of
the tcp case so we can see if there is a memory leak.
On Sun, 11 Dec 2016 at
Test attached
--
You received this message because you are subscribed to the Google Groups "H2
Database" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to h2-database+unsubscr...@googlegroups.com.
To post to this group, send email to h2-database@googlegro
