이더리움 클라이언트의 스토리지 관리 parity garbage collection&geth state storage

작성자 :

11주차 유진영

parity는 touched empty account와, balance를 기준으로 정한 dust account를 삭제할수 있게 하였다. (contract account 포함)

우리는 오랜기간 사용하지않는 account를 compress하여 저장하고, 복구가 가능하도록 하려한다.

Parity는 removeDustContract option으로 실행시 garbage collection을 수행.

kill_garbage()함수를 이용하여 touched empty account 나 dust account(EOA)를 삭제한다.

touched empty account : 0 을 전송 받았지만(*거래에는 참여하여 account의 state가 trie에 포함됨) tx를 발생시킨적 없는 계정

EIP 161 중 touched와 empty

An account is considered to be touched when it is involved in any potentially state-changing operation. This includes, but is not limited to, being the recipient of a transfer of zero value.

An account is considered empty when it has no code and zero nonce and zero balance.

(empty_and_is_null() 중 is null() 역시 nonce = balance == 0 이면서 storage는 empty)

*state-bloating attack 방지를 위해 Account생성 후 바로 trie에 추가되지 않고, 트랜잭션이 성공적으로 실행된것이 확인된 후(해당 트랜잭션이 포함된 블록이 채굴된 후) 추가된다고 한다.

(old_balance와 비교해) balance가 줄어들었다면

해당하는 basic account(즉, EOA계정) 삭제

"dustProtectionTransition" - Activates Mainnet specific EIP-168 and EIP169 - Not active by default.

"nonceCapIncrement" - U64 - Nonce cap increase per block. Nonce cap is only checked if dust protection is enabled..

CleanDustMode가 WithCodeAndStorage

Off, BasicOnly(basic dust만 삭제), WithCodeAndStorage(basic and contract dust 둘다 삭제)

EIP168.C, 169.C 를 레퍼런스로함

EIP-168.C

An account is considered dust when it has a balance less than the transaction's gas_price multiplied by 21000 and no code.

EIP-169.C

a. Newly created account entries get a nonce equal to the current block number times MAX_TXS_PER_ACCT_PER_BLOCK.

b. Transactions can only be sent from a nonempty account.

c. If an account has nonzero nonce, then a transaction sent from it may be included in the current block iff:

the nonce divided by MAX_TXS_PER_ACCT_PER_BLOCK is no greater than the current block number.The account nonce is incremented as normal if the transaction is included.

Example MAX_TXS_PER_ACCT_PER_BLOCK could be 64.