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lbehnke / h2database

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Page store: performance bugs #102

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Major performance bugs in new page store, for CREATE INDEX.  

org.h2.index.PageBtreeIndex.add(org.h2.engine.Session,org.h2.result.Row)
Lines: 79-95.  Appear to force full LOB read during index creation, for
some indexes. Even when LOB is not being indexed. 

org.h2.store.PageStore.checkpoint() appears to be calling
org.h2.FileStore.write(byte[],int,int) a ton of times -- 4.5 million calls
in my case, when indexing an 80K row table 3 times. 

Issue (and detailed tests/profiling) submitted by email, this is just
formal record.

Original issue reported on code.google.com by buckyba...@gmail.com on 24 Jul 2009 at 4:47

GoogleCodeExporter commented 9 years ago

Original comment by thomas.t...@gmail.com on 6 Aug 2009 at 6:32

GoogleCodeExporter commented 9 years ago 
PageBtreeIndex.add should not re-add the LOBs, I will fix that.

Checkpoint currently re-writes all empty pages. This is a performance
problem, but currently I will not fix it because checkpoint is not
called that often. At some point I will fix it.

Original comment by thomas.t...@gmail.com on 6 Aug 2009 at 6:36

GoogleCodeExporter commented 9 years ago 
The LOB problem should be fixed now.
Page store optimizations will have to wait until all bugs are fixed.

Original comment by thomas.t...@gmail.com on 10 Aug 2009 at 3:38

GoogleCodeExporter commented 9 years ago

Original comment by thomas.t...@gmail.com on 10 Aug 2009 at 3:38