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Oracle memory troubleshooting using analysis on heapdumps

This blogpost is about analysing Oracle heap dumps. It is an extension to earlier work, Tanel Poder’s heap dump analyzer. So hat tip to Tanel, he’s done the hard work, I merely increased the presentation options. The heap analyser script that I wrote analyses Oracle heapdumps from the trace file that the dump was written to by the Oracle database. Because the heap dump representation is the same between PGA and SGA memory, it can work on both. The reason for this is that memory management is done by the same memory manager, and is commonly called ‘kgh’ (kernel generic heap) managed memory.

Please mind that for PGA analysis, not all memory is managed by the kgh memory manager. For example memory used for networking (sqlnet) is allocated totally outside of the kgh memory manager.