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From Jim Newsham <jnews...@referentia.com>
Subject memory required for syscs_util.syscs_compress_table
Date Fri, 21 May 2010 03:50:40 GMT


Is there an upper-bound on the memory required to run 
syscs_util.syscs_compress_table?  What determines how much memory is 
required (for example, should it be fixed or proportional to table 
size?  affected by page size or page cache size?)  We're occasionally 
getting out of memory errors when calling this function.

For example, in testing our app (which is not small, but is in a pretty 
quiescent state during my testing), the app is in a stable state at 
approx 116M with max heap at 256M, and then running a series of table 
compresses (strictly one-at-a-time) eventually gives OOME.  So it seems 
that 140M is not enough to accommodate this function.  I did get all 
tables to compress successfully when using 512M max heap, but I need to 
understand how much memory Derby will require, and if the requirements 
will grow with larger tables.

I'm using Derby 10.4.2.  The "sequential" parameter is set to false.


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