the more the memory, the long the hash list. yes, but who can say it will increase the time to scan hash list ? and increase latch time ?
that's strange for me . that's depended on how many physical data fetch into memory.maybe this is abstract concept.
if you just want to fect 10 rows in to memory,maybe one block is enough . do you think it will increase latch time ? it will increase scan time ?
but if you fetch 100000 rows , of couse , when memory is not large, even there are no enough memory in hash list, then written dirth block and release memory . from this point of view, when you locate a large memory, maybe it will increase scan time and latch time.
because when memory is not large, and no enough memory in hash list, oracle just flush dirth memory. it needn't scan so long hash list. but if you locate a large memory, than even there are free memory, oracle should scan so long list.
so the conclusion is : i don't think increate sga will cause the latch time and scan time increase .this is depened on how many data do you want to fetch .
appendix:
this is complex question. we also should consider how many data should fetch into memory and how many dirth data written back to disk .
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