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From Alan Burlison <Alan.Burli...@sun.com>
Subject Re: btree overflow during insert
Date Thu, 13 Nov 2008 16:23:53 GMT
Knut Anders Hatlen wrote:

> I have logged DERBY-3947 and attached a reproducible test case.
> Note that it is possible to set derby.storage.pageSize just for a single
> index by issuing
> CALL SYSCS_UTIL.SET_DATABASE_PROPERTY('derby.storage.pageSize', '32768')
> right before the index in question is created and resetting it with
> CALL SYSCS_UTIL.SET_DATABASE_PROPERTY('derby.storage.pageSize', null)
> afterwards.

Thank-you very much for doing this, and the comments in the bug are 
useful too as they gives me a hint as to how we might change the table 
definition to avoid the problem altogether.  We can probably work around 
this by reducing the length of the varchar column being indexed, which 
is a little aggressively-sized (32672).  Failing that we can use the 
workaround you suggest.

One thing I'm not quite clear on: does Derby allocate the full length of 
a varchar column in an index that uses it?  In our case, although the 
column is varchar(32672), only a small fraction of it is used, 4Kb at most.

Alan Burlison

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