Mike Matrigali <[email protected]> writes: > Also note that these are all estimates within the system. As Knut > pointed out there are some known problems with the estimates. And > even with fixes he has suggested, the code is probably just guessing > with things like blobs/clobs.
I haven't verified, but I think HashJoinStrategy uses DataTypeDescriptor.estimatedMemoryUsage() to estimate how much memory the hash table will consume. That method has no case for BLOB or CLOB, so it looks as if it will return zero for LOB columns. If that's so, it will definitely overestimate how many rows fits in maxMemoryPerTable kilobytes if the rows contain LOBs. -- Knut Anders
