******************************************************
HEAP DUMP heap name="pga heap" desc=0x185e1d8
extent sz=0x213c alt=40 het=32767 rec=0 flg=3 opc=3
parent=0 owner=0 nex=0 xsz=0xfe28
EXTENT 0
Chunk 1aa72d4 sz= 65056 free " "
EXTENT 1
Chunk 1946d84 sz= 8500 free " "
EXTENT 2
Chunk 195107c sz= 8500 free " "
EXTENT 3
Chunk 195530c sz= 8500 free " "
EXTENT 4
Chunk 1a9749c sz= 65056 free " "
EXTENT 5

That's indeed pga heap .Do you know any work around to ensure that the database does not crashes ...