Thanks a lot for all the answers. But my problem is still not solved. I tried larger page size but it didnt shrink the size. 42000 fields of the kind i sent you still need 60MB without compression and 35MB with compression. If I store them (as singles) compressed to a normal file then I reach 10Mb and if i store them simply as a concat of texts to a file then it results into a size of 20MB.
The idea of Thomas to store this texts as a zip file and get them if needed without random access doesnt help either due to the missing random access. The other idea of Thomas, that half empty b trees might affect the size cant be true since i created a table with an indexed INTEGER field. Hence the large text field is only stored aside the indexed field. and 42000 INT values dont result into a B tree of 40MB :-). @Dario: The script idea doesnt help either (Its simply not a doable task when users use embedded databases of the size of some gigs) I think that the only thing I can do now is to store the large field from my db to a file and single compressed and storing the location to the database Another and maybe a little dumb question is, how to activate the lobsindatabase option. Is the a connection parameter? On Oct 13, 11:17 pm, Thomas Mueller <[email protected]> wrote: > Hi, > > If you have a read-only database, you could use "Read Only Databases > in Zip or Jar File" to get a better compression > ratio:http://h2database.com/html/features.html#database_in_zip- but if you > compress the whole file / database, you can't do random access any > longer. That means reading from the database is much slower. > > > Do you have any idea why H2 enlarges the data so much? > > According to my test, the overhead of H2 is quite low when compared to > other databases. > > Databases do have some space overhead, because typically 50% of a > b-tree is empty. For H2 (and some other databases) there is a way to > reduce this overhead - > seehttp://h2database.com/html/performance.html#database_performance_tuning > "Sorted Insert Optimization". But this only works well if you don't > have many updates (updates will split the pages). > > Regards, > Thomas -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/h2-database?hl=en.
