[Patch] Optimize BitField for use in DBs with large BLOBs

Kamstrup Erlandsen Software Developer at State and University Library of Denmark --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups H2 Database group. To post to this group, send email to h2-database@googlegroups.com

Re: NIO storage

2009/3/6 Jan Kotek openco...@gmail.com 1) My patch adds two more classes and does not change others. It is completely __OPTIONAL__ 2) 1.3 is __still supported__, but can use only classical file storage. Multiple version of jars for each VM are __not needed__. 3) NIO does not depend on 1.5

Re: [Patch] Optimize BitField for use in DBs with large BLOBs

), childId VARCHAR(255) ); CREATE UNIQUE INDEX pc ON summa_relations(parentId,childId); CREATE INDEX c ON summa_relations(childId); -- Cheers, Mikkel Kamstrup Erlandsen, State and University Library of Denmark --~--~-~--~~~---~--~~ You received this message

Re: [Patch] Optimize BitField for use in DBs with large BLOBs

2009/3/10 Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com: 2009/3/6 Thomas Mueller thomas.tom.muel...@gmail.com Hi, I'm sorry I don't understand why getLastSetBit can take much time... Could you describe your use case please? What database version do you use? If you use version 1.0.x

Re: Error from console when doing a simple select

2009/3/8 Jezzper j...@jezzper.dk: Hi I have used the H2 console against a Firebird database and the queries worked well. I have now ported the database to H2 (because it is much much faster). When I now do the (any) simple selects like Select * from weblogdata I get an error: Column

Re: NIO storage

2009/3/11 Jan Kotek openco...@gmail.com Hi Thomas, Load position is right. FileChannel is safe, but I would strongly discurage to put MappedByteBuffer as default implementation in next 10 years :-) I run your complete benchmarks  and can confirm that both NIO implementations are slower.

Re: [Patch] Optimize BitField for use in DBs with large BLOBs

2009/3/10 Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com: 2009/3/10 Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com: 2009/3/6 Thomas Mueller thomas.tom.muel...@gmail.com Hi, I'm sorry I don't understand why getLastSetBit can take much time... Could you describe your use case

Re: Large Database Performance

2009/6/8 Lucky Luke ingmar.koec...@gmail.com: Hello, I just found out about H2, and I was wondering how well it handles large databases (e.g. 50Gb - 100Gb in size). We have a database that has 2 dozen lookup tables that are small, and about half a dozen tables that are potentially very

Re: Large Database Performance

... On Jun 11, 8:28 am, Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com wrote: 2009/6/8 Lucky Luke ingmar.koec...@gmail.com: Hello, I just found out about H2, and I was wondering how well it handles large databases (e.g. 50Gb - 100Gb in size). We have a database that has 2 dozen lookup

Re: Large Database Performance

BY mtime LIMIT 1000 Best of luck! Mikkel On Jun 15, 10:10 am, Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com wrote: 2009/6/12 Dror dro...@hotmail.com: Hi Mikkel, I wonder about the query performance, we have similar configuration with only ~1M records in a single table

Re: Primary key takes precedence over index?

2009/9/11 Thomas Mueller thomas.tom.muel...@gmail.com: Hi, Currently, the optimizer doesn't calculate the cost of using the ORDER BY index. It does use this index only if no other index is used. I know this needs to be improved... I actually started to look into this myself before I sent

Re: database 900 MB slow to open, is it normal?

2009/12/7 Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com: 2009/12/7 Sylvain Pointeau sylvain.point...@gmail.com: Hi, I would like to know if this is normal that this is slow (15 seconds) to open a (large?) database (900MB)? I am using the web interface provided in the package. Best

Re: database 900 MB slow to open, is it normal?

2009/12/7 Sylvain Pointeau sylvain.point...@gmail.com: Hi, I did what you suggest, opening it with the shell and then quit to properly close the DB. yes it goes faster to open it after that but still it uses 8 seconds. Is this time linear with the db size? I put 1GB to the java process. the

Re: database 900 MB slow to open, is it normal?

to H2? Nah, I don't think it makes any difference. I am sorry, but I am a bit at a loss as to what could be your problem... Cheers, Mikkel On Tue, Dec 8, 2009 at 8:25 AM, Mikkel Kamstrup Erlandsen mikkel.kamst...@gmail.com wrote: 2009/12/7 Sylvain Pointeau sylvain.point...@gmail.com: Hi

Re: H2 performance in sun solaris

2009/12/7 sam pio hiii...@gmail.com: Hi all,         we have an application which uses H2 as an embedded database.In that application we constantlly write into the db synchronizing. and we also query and update simultaneously. I find that the overall operation of my program is 4 times

Re: table lock for reads

2009/12/16 Chuck Remes cremes.devl...@mac.com: On Dec 16, 2009, at 4:20 AM, Istvan Soos wrote: Hi, I've read somewhere in the docs that h2 has a table lock on writes - and while the write is locking, there is no concurrent read. Is it true that the writes will lock the reading threads too?