I do use MULTI_THREADED=1 in H2 URL connection. On Wednesday, January 30, 2013 9:34:26 PM UTC-8, Thomas Mueller wrote: > > Hi, > > > queries were taking longer as I added more concurrent > > Yes, this is somewhat normal. If you use MULTI_THREADED=1 it should be > less of a problem, but maybe you have hit the maximum throughput of the > computer, or a limitation of H2 itself. If you can't use MULTI_THREADED=1 > then H2 can't get faster with multiple threads. > > Regards, > Thomas > > > On Wed, Jan 30, 2013 at 10:11 PM, Sri <[email protected] > <javascript:>>wrote: > >> I had added all necessary indexes required for my queries and they >> perform very well. >> It's been performing very good with single/few user/thread and is getting >> degraded as I add more concurrent users/threads. >> >> I had also profiled using built-in profiler and queries were taking >> longer as I added more concurrent users/threads. >> >> -Sri >> >> On Wednesday, January 30, 2013 12:55:26 PM UTC-8, Thomas Mueller wrote: >> >>> Hi, >>> >>> > I tied using in-memory db doesn't improve the performance at all. >>> >>> Did you read the performance docs yet - http://h2database.com/html/** >>> performance.html <http://h2database.com/html/performance.html> ? >>> Specially the built-in profiler and indexes. >>> >>> > LOG=0, LOCK_MODE=0 and FILE_LOCK=NO has any effect on the performance? >>> >>> Not if indexes are missing, queries are slow and so on. LOG=0 might >>> double performance, but that's it. lock mode and file lock don't typically >>> improve performance, they are just dangerous. >>> >>> Regards, >>> Thomas >>> >>> >>> >>> On Wed, Jan 30, 2013 at 8:53 PM, Sri <[email protected]> wrote: >>> >>>> I tied using in-memory db doesn't improve the performance at all. Both >>>> in-memory and server have similar turn around times. >>>> >>>> I was looking at some of the H2 documentation and came across below >>>> one. As I mentioned earlier DB is only for reads so by doing LOG=0, >>>> LOCK_MODE=0 and FILE_LOCK=NO has any effect on the performance? >>>> >>>> "Some features are known to be dangerous, *they are only supported for >>>> situations where performance is more important than reliability*. >>>> Those dangerous features are: >>>> >>>> - Disabling the transaction log or FileDescriptor.sync() using >>>> LOG=0 or LOG=1. >>>> - Using the transaction isolation level READ_UNCOMMITTED (LOCK_**MODE >>>> 0) while at the same time using multiple connections. >>>> - Disabling database file protection using (setting FILE_LOCK to NO in >>>> the database URL). >>>> - Disabling referential integrity using SET REFERENTIAL_INTEGRITY >>>> FALSE." >>>> >>>> >>>> -Sri >>>> >>>> On Tuesday, November 13, 2012 7:32:35 PM UTC-8, Kartweel wrote: >>>>> >>>>> Other people might have some suggestions, but I guess if you try it >>>>> on a solid state disk or just trial as an in memory database and see if >>>>> it >>>>> performs faster. >>>>> >>>>> Or you could also try it on a ram disk and see if it improves >>>>> performance. That way you don't need to try any other hardware. >>>>> >>>>> At least then you'll know the disk was the bottleneck. >>>>> >>>>> Ryan >>>>> >>>>> On 14/11/2012 7:03 AM, Sri wrote: >>>>> >>>>> Sorry I was looking into some other things...now I got back to this.. >>>>> >>>>> How do we determine if disk io is capped? >>>>> >>>>> I do see disk io is varying (up and down from 40kb- 200kb and >>>>> occasionally shoots up to 950kb) all the time when I observed windows >>>>> resource monitor. >>>>> >>>>> -Sri >>>>> >>>>> On Friday, November 2, 2012 2:23:03 PM UTC-7, Kartweel wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> Makes sense to me. If cpu isn't the issue (which I doubt it would be >>>>>> in a database, but maybe the encryption adds a lot of overhead?) then >>>>>> adding more threads would increase the time proportionally + >>>>>> synchronisation overhead. Also there would be more work for the disk >>>>>> seeking between all the different locations. >>>>>> >>>>>> So are you saying that disk io is increasing with each thread you >>>>>> add? or is it capped? both bandwidth and iops ? >>>>>> >>>>>> On 3/11/2012 4:44 AM, Sri wrote: >>>>>> >>>>>> Disk IO looks good too...can't seem to find what is the issue... >>>>>> >>>>>> On Thursday, November 1, 2012 2:36:21 PM UTC-7, Kartweel wrote: >>>>>>> >>>>>>> How about disk io?, usually the disk is the bottleneck. >>>>>>> >>>>>>> On 2/11/2012 3:44 AM, Sri wrote: >>>>>>> > Hi, >>>>>>> > >>>>>>> > I am running H2 DB in server mode and using it for read only. It's >>>>>>> > been performing very good with single user/thread and the >>>>>>> performance >>>>>>> > is getting degraded as I add more concurrent users/threads. >>>>>>> > >>>>>>> > Single user/thread --> about 100ms >>>>>>> > 10 users/threads --> about 230ms >>>>>>> > 15 users/threads --> about 320ms >>>>>>> > 20 users/threads --> about 440ms >>>>>>> > 25 users/threads --> about 550ms >>>>>>> > 40 users/threads --> about 900-1000ms >>>>>>> > 50 users/threads --> about 1300-1400ms >>>>>>> > >>>>>>> > Please see the attached screenshot for CPU, heap and thread >>>>>>> > monitoring. I do not see the problem of CPU being max out or not >>>>>>> > enough memory or not scaling threads as I add more users. >>>>>>> > >>>>>>> > H2 Version:h2-1.3.166 >>>>>>> > Url: >>>>>>> > jdbc:h2:tcp://localhost:9092/<****<DB absolute >>>>>>> > path>>;MULTI_THREADED=1;CACHE_****SIZE=<<cashesize>>;CIPHER=AES;** >>>>>>> **IFEXISTS=TRUE >>>>>>> > >>>>>>> > <<cashesize>> ==> tried different values, defualt-16mb, 128mb, >>>>>>> 256mb, >>>>>>> > 512mb and 1024mb (supplied in KB though) >>>>>>> > >>>>>>> > FYI, >>>>>>> > Each thread is executing lot of queries (around 15-20) and some of >>>>>>> > them are recursive queries (to fetch heirachy data). >>>>>>> > >>>>>>> > >>>>>>> > Please let me know if anybody run into the same problem and how >>>>>>> did >>>>>>> > you resolve. >>>>>>> > >>>>>>> > Thanks in advance. >>>>>>> > -Sri >>>>>>> > -- >>>>>>> > You received this message because you are subscribed to the Google >>>>>>> > Groups "H2 Database" group. >>>>>>> > To view this discussion on the web visit >>>>>>> > https://groups.google.com/d/**ms**g/h2-database/-/hbZ9WV8cFWEJ<https://groups.google.com/d/msg/h2-database/-/hbZ9WV8cFWEJ> >>>>>>> **. >>>>>>> > To post to this group, send email to [email protected]. >>>>>>> > To unsubscribe from this group, send email to >>>>>>> > h2-database...@googlegroups.**co**m. >>>>>>> > For more options, visit this group at >>>>>>> > http://groups.google.com/**group**/h2-database?hl=en<http://groups.google.com/group/h2-database?hl=en>. >>>>>>> > >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "H2 Database" group. >>>>>> To view this discussion on the web visit https://groups.google.com/d/ >>>>>> **ms**g/h2-database/-/njQ5VJHkPvEJ<https://groups.google.com/d/msg/h2-database/-/njQ5VJHkPvEJ> >>>>>> **. >>>>>> To post to this group, send email to [email protected]. >>>>>> To unsubscribe from this group, send email to >>>>>> h2-database...@googlegroups.**co**m. >>>>>> For more options, visit this group at http://groups.google.com/** >>>>>> group**/h2-database?hl=en<http://groups.google.com/group/h2-database?hl=en> >>>>>> . >>>>>> >>>>>> >>>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "H2 Database" group. >>>>> To view this discussion on the web visit https://groups.google.com/d/* >>>>> *ms**g/h2-database/-/YscoajbGnT4J<https://groups.google.com/d/msg/h2-database/-/YscoajbGnT4J> >>>>> **. >>>>> To post to this group, send email to [email protected]. >>>>> To unsubscribe from this group, send email to h2-database...@** >>>>> googlegroups.**com. >>>>> For more options, visit this group at http://groups.google.com/**group >>>>> **/h2-database?hl=en<http://groups.google.com/group/h2-database?hl=en> >>>>> . >>>>> >>>>> >>>>> -- >>>> 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...@**googlegroups.com. >>>> >>>> To post to this group, send email to [email protected]. >>>> Visit this group at >>>> http://groups.google.com/**group/h2-database?hl=en<http://groups.google.com/group/h2-database?hl=en> >>>> . >>>> For more options, visit >>>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> >>>> . >>>> >>>> >>>> >>> >>> -- >> 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 [email protected] <javascript:>. >> To post to this group, send email to [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/h2-database?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > >
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