Thomas, The keys are (theoretically) added in ascending order. But there could be a few occurrence of out of order keys.
I will try your suggestions and let you know how it pans out. Thanks again for all your work on H2 (and Noel's as well :-) ) On Saturday, September 21, 2013 2:04:50 PM UTC-4, Thomas Mueller wrote: > > Hi, > > > MVStore (version 1.3.172) > > It is changing quite quickly, I suggest to use the latest version > (1.3.173, or even better, the latest automated build at > http://h2database.com/html/download.html (direct link: > http://www.h2database.com/automated/h2-latest.jar ) > > > I simply use a Map<String,String> where key and values are equal (since > null values are not permitted) > > It would be a bit more efficient to use Map<String, Integer> and use the > key "1". If you use compression, disk space savings wouldn't be that big, > but it should be a little bit faster. > > > I really do not care about the versioning capabilities of the MVStore > > I probably over-estimated that versioning is very useful. I found it is > not that important for the database engine itself :-) But it is nice to > have it, for example to support concurrent operations (read, write and > store). I will make it more auto-commit and auto-store, so that you don't > have to call commit / store yourself. The TransactionStore already does > that, and it seems to work fine, but it would be better if the MVStore > would do it itself I guess. > > > Also I pretty much only add keys (never remove them) > > Do you add them in random order, or in somewhat ascending / descending > order? For random order, possibly a "log-structured merge tree" mode would > make sense (I will need to think about that). > > > Obviously there is more in the store than just my data :-) > > Well, I guess yes. How often do you call commit() and store()? It's > relatively important that they are not called too often. Until auto-commit > is implemented, I suggest to call commit() every 10000 inserts, and store() > never yourself, but rely on auto-store in the background thread (this is > already implemented in the current trunk). > > Regards, > Thomas > > > > > > > > On Sat, Sep 21, 2013 at 4:31 PM, Igor castang > <[email protected]<javascript:> > > wrote: > >> Hello, >> >> I am testing the use the MVStore tool standalone. (version 1.3.172) >> >> My use case is simple. >> >> I just want to check if a string sequence read from my application has >> already been seen previously. >> I simply use a Map<String,String> where key and values are equal (since >> null values are not permitted). And when a sequence is tested I just test >> for the existence of the key in the Map, and add it if unseen so far. >> >> The number of keys in the map will go to a billion and more. >> >> I really do not care about the versioning capabilities of the MVStore. I >> just want the last version. Also I pretty much only add keys (never remove >> them) >> >> My issue is that the store gets really really big, 100GB+, and I am using >> compression on the store . Obviously there is more in the store than just >> my data :-) >> And if I iterate the values in my map and create a new store the size of >> the new store is dramatically smaller. >> >> Now my question : >> >> - is there a setting or a way to use the versionning methods to keep the >> disk utilization to a lower level ? >> >> >> thanks >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> -- >> 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. >> For more options, visit 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]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/h2-database. For more options, visit https://groups.google.com/groups/opt_out.
