I need to retain not only the most recent 128 block in full mode but e.g. last 1000 blocks for my purposes. The greater the value of reexec the longer the tracing will take because more blocks have to be re-executed to regenerate the target state. So I want to make it much faster by saving more latest blocks. Also I have no need to use archive mode cause it takes a lot of space. To summer up, my goal is to improve geth source code.
I've changed only TriesInMemory (core/blockchain.go) and defaultTraceReexec (eth/tracers/api.go) vars but it's not enough I guess