I have no idea what this line is doing in detail, but I got the same speed now as if I restart
echo 3 | sudo tee /proc/sys/vm/drop_caches Just want to share it with you. Am Donnerstag, 20. November 2014 14:37:23 UTC+1 schrieb Curtis Mosters: > > Yeah reboot is working fine. Now I get the uncached time again with it. > > But rebooting takes so many time and I have to reconnect again and again > via shell. > > I also tried sync. But when I type it nothing happens. Also searched for a > way to use it, but it seems that noone has a good solution there. > > Docker and vagrant I never tried, but sounds like a good solution. > > And btw I know that this test here might not be the very best. But since > Neo4j does not kill the cache I have to do it this way. Otherwhise I cannot > compare it to my other database. The one is clearing cache by shutdown. > That's how it should be I think. > > Thanks Michael > > Am Donnerstag, 20. November 2014 11:54:24 UTC+1 schrieb Michael Hunger: >> >> As this is *operating system caches* we're talking about, you can try >> "sync" on unix. >> >> Or reboot. >> >> It might also work to run Neo4j in a container (docker, vagrant) and >> restart / resume that container. >> >> On Thu, Nov 20, 2014 at 9:29 AM, 'Curtis Mosters' via Neo4j < >> [email protected]> wrote: >> >>> Yeah but the issue is that I have 10 comparisons. Each having let's say >>> the 10 same words to search for. >>> >>> So after the first search Neo4j already knows where they are and is >>> faster now. That's the issue I have. Real word is something else, where you >>> would change those words. But I don't want to think always about new words >>> to search for. >>> >>> So clearing cache would be way better. IS there really no way to do it? >>> >>> Also tried* killall -9 java*, but not working. >>> Also followed On linux, see: http://linux-mm.org/Drop_Caches >>> <http://www.google.com/url?q=http%3A%2F%2Flinux-mm.org%2FDrop_Caches&sa=D&sntz=1&usg=AFQjCNGlvcLH54xciQ5X723RMpzCoWQfBg> >>> >>> but nothing happens? >>> >>> Am Mittwoch, 19. November 2014 22:55:23 UTC+1 schrieb Michael Hunger: >>>> >>>> But for realistic use-cases you will have exactly that setup, that you >>>> have hot data in your OS' file-system and also database caches, >>>> >>>> that is the state you want to reach for real benchmarks as this >>>> represents the real world usage, not the cold caches after a computer and >>>> database start. >>>> >>>> The cold cache numbers can be completely ignored imho as they only >>>> measure the speed of the disk and the loading mechanism of the FS and >>>> database to get data loaded. >>>> >>>> Same goes for JVM JIT and other optimizations that happen behind the >>>> scenes (by OS, JVM, DB) >>>> >>>> Michael >>>> >>>> On Wed, Nov 19, 2014 at 9:37 PM, Jacob Hansson <[email protected] >>>> > wrote: >>>> >>>>> Hey mate, >>>>> >>>>> yeah, this does clarify it. It is very likely that what is happening >>>>> is that the OS is caching the index files in RAM, so the second time you >>>>> run the database (even after a restart), it does not have to hit disk. >>>>> You >>>>> could verify that this is the case by evicting the OS page cache between >>>>> your benchmarks. What OS are you using? >>>>> >>>>> On linux, see: http://linux-mm.org/Drop_Caches >>>>> On mac, you should be able to run 'purge' to clear the caches, see: >>>>> http://www.cnet.com/news/purge-the-os-x-disk-cache-to- >>>>> analyze-memory-usage/ >>>>> >>>>> For windows there does not seem to be a vendor-provided mechanism to >>>>> do this, see here for alternatives: http:// >>>>> stackoverflow.com/questions/7405868/how-to-invalidate-the- >>>>> file-system-cache >>>>> >>>>> /jake >>>>> >>>>> On Wed, Nov 19, 2014 at 12:25 PM, 'Curtis Mosters' via Neo4j < >>>>> [email protected]> wrote: >>>>> >>>>>> Hi Jacob, well yeah here is an example: >>>>>> >>>>>> START n=node:titles("title:solar") RETURN count(*) >>>>>> >>>>>> If I do this right after the import. It needs *180 sec*. But doing >>>>>> this a second time needs *3 sec* and after that again just needs 1,5 >>>>>> sec, but after that there is no more improvement. Also after doing some >>>>>> stuff in the settings, I never get to the 180 sec again.=/ >>>>>> >>>>>> But if you think now it is just that word. No it's not. Also tested 9 >>>>>> others and here it was lasting round about 60 sec, too. But searching >>>>>> again >>>>>> on them was 1-2 sec. >>>>>> >>>>>> Also after restarting the Neo4j server it is still that fast (1-3 >>>>>> sec). And yeah I need the uncached result time for my comparison. It is >>>>>> not >>>>>> correct if I continue now with cached things. >>>>>> >>>>>> Maybe now it's way clearer? If not just let me know. Thank you. >>>>>> >>>>>> Am Mittwoch, 19. November 2014 18:35:38 UTC+1 schrieb Jacob Hansson: >>>>>>> >>>>>>> Curtis, >>>>>>> >>>>>>> can you clarify what you mean by caching, and how you are >>>>>>> determining that things are getting cached? >>>>>>> >>>>>>> If you are talking about caching of the actual data, note that there >>>>>>> are several layers of caching - the OS will cache files in its page >>>>>>> cache, >>>>>>> for instance. If you want to work around that in your testing you need >>>>>>> to >>>>>>> ask the operating system to flush its caches. >>>>>>> >>>>>>> /j >>>>>>> >>>>>>> On Wed, Nov 19, 2014 at 7:36 AM, 'Curtis Mosters' via Neo4j < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Well for my Benchmark I need a clear Cache because otherwhise Neo4j >>>>>>>> is always caching and faking my results in a bad way. >>>>>>>> >>>>>>>> So I tried: >>>>>>>> cache_type=none >>>>>>>> cache.memory_ratio=0.0 >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> in the neo4j.properties. Had no real impact still caching. >>>>>>>> >>>>>>>> Also found something from Michael with jconsole: >>>>>>>> http://stackoverflow.com/questions/26189351/neo4j-server- >>>>>>>> clear-the-cache-in-ram >>>>>>>> But really no idea what he means. =( I meant the JMX call I found >>>>>>>> http://stackoverflow.com/questions/12621963/clear-ehcache- >>>>>>>> of-remote-server >>>>>>>> But also not sure if it is the right thing to clear. >>>>>>>> >>>>>>>> Here I found infos about the caching: http://neo4j.com/docs/stable/ >>>>>>>> configuration-caches.html >>>>>>>> But nothing worked or was in my mind useful to test. >>>>>>>> >>>>>>>> Then I gone through all settings here: >>>>>>>> http://neo4j.com/docs/stable/kernel-configuration.html >>>>>>>> But yeah except the two lines above nothing looking satisfying. >>>>>>>> Even tried query_cache_size=0 but here I got a funny error message >>>>>>>> then, so >>>>>>>> yeah dunno what that setting means. >>>>>>>> >>>>>>>> Then I was thinking that setting the neo_mapping stuff to 0 might >>>>>>>> help. But then I found http://grokbase.com/t/gg/neo4j >>>>>>>> /1312y592r4/caching-the-whole-graph which says that setting to 0 >>>>>>>> is like limiting to infinity. >>>>>>>> >>>>>>>> Ohman so nothing worked to disable the cache. Why is it so hard to >>>>>>>> give a setting disable cache or clearing the cache after server is >>>>>>>> shut >>>>>>>> down. >>>>>>>> >>>>>>>> Really need this =/ >>>>>>>> >>>>>>>> Thank you >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "Neo4j" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>>>> >>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Neo4j" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Neo4j" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Neo4j" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- You received this message because you are subscribed to the Google Groups "Neo4j" group. 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