Hey Göran, did you find anything helpful? 27 Haziran 2016 Pazartesi 18:52:57 UTC+3 tarihinde Göran Schwarz yazdı: > > Hi Noel, and thanks for the answer! > > MULTI_THREADED is normally OFF (it was just an test to see if that was > going to help, but it did not, so I'm running *without* that option now) > > LOB: Sorry I can't remove the LOB columns, then I have to "redesign" > everything from scratch (meaning: breaking up CLOBS into smaller chunks and > store them as varchar(255) or similar, then assemble them again on selects, > but that is a *major* job) > > Open Trans: I have no open transactions, according to: select * from > INFORMATION_SCHEMA.SESSIONS, the column CONTAINS_UNCOMMITTED is false > between my "insert batches" > > Restart the app: > * No the problem still exists after application is restarted (using the > same URL, or big db-file) > * But if I create a *new* database on the fly (close current db-file & > create/open a new db-file) the "storage" time goes down *drastically* (from > several minutes (approx 8-10 minutes) to "normal" time, which is approx 1-2 > seconds for 15.000 records, which is applied in ~20 different transactions) > > So my guess is that we do to much cleanup-stuff in the commit phase (or > trying to *find* things to cleanup)... and when the database becomes to > large it just "loops" or "spend to much time" at > org.h2.mvstore.Page$PageChildren.removeDuplicateChunkReferences(Page.java:1094) > I haven't really investigated the code path it takes in depth, but at some > point it reaches a threshold where things just takes to long time for a > commit! > > In my mind: a commit should be quick (write the "last" log pages to disk, > and possible (if we want recover-ability and consistency) wait for for the > IO to complete), and if we need to do "cleanup" work it should be done in > some "housekeeper-post" phase... > but I'm not sure how H2 is designed when it comes to this: The design is > not really my concern, it's simply the long commit times when a database > becomes to big! > > BTW: I have to thank you for all the hard work you have put into H2 > /Goran > >
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