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]>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]. > 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. > -- 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.
