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/c >>>>>> onfiguration-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/k >>>>>> ernel-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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