50 lines
2.7 KiB
Markdown
50 lines
2.7 KiB
Markdown
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# Pending State
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Learn how Ethermint handles pending state queries. {synopsis}
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## Pre-requisite Readings
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- [Tendermint Mempool](https://docs.tendermint.com/master/tendermint-core/mempool.htm) {prereq}
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## Ethermint vs Ethereum
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In Ethereum, pending blocks are generated as they are queued for production by miners. These pending
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blocks include pending transactions that are picked out by miners, based on the highest reward paid
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in gas. This mechanism exists as block finality is not possible on the Ethereum network. Blocks are
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committed with probabilistic finality, which means that transactions and blocks become less likely
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to become reverted as more time (and blocks) passes.
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Ethermint is designed quite differently on this front as there is no concept of a "pending state".
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Ethermint uses [Tendermint Core](https://docs.tendermint.com/) BFT consensus which provides instant
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finality for transaction. For this reason, Etheremint does not require a pending state mechanism, as
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all (if not most) of the transactions will be committed to the next block (avg. block time on Cosmos chains is ~8s). However, this causes a
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few hiccups in terms of the Ethereum Web3-compatible queries that can be made to pending state.
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Another significant difference with Ethereum, is that blocks are produced by validators or block producers, who include transactions from their local mempool into blocks in a
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first-in-first-out (FIFO) fashion. Transactions on Ethermint cannot be ordered or cherry picked out from the Tendermint node [mempool](https://docs.tendermint.com/master/tendermint-core/mempool.html#transaction-ordering).
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## Pending State Queries
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Ethermint will make queries which will account for any unconfirmed transactions present in a node's
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transaction mempool. A pending state query made will be subjective and the query will be made on the
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target node's mempool. Thus, the pending state will not be the same for the same query to two
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different nodes.
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### JSON-RPC Calls on Pending Transactions
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- [`eth_getBalance`](./../api/json-rpc/endpoints.md#eth_getbalance)
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- [`eth_getTransactionCount`](./../api/json-rpc/endpoints.md#eth-gettransactioncount)
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- [`eth_getBlockTransactionCountByNumber`](./../api/json-rpc/endpoints.md#eth-getblocktransactioncountbynumber)
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- [`eth_getBlockByNumber`](./../api/json-rpc/endpoints.md#eth-getblockbynumber)
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- [`eth_getTransactionByHash`](./../api/json-rpc/endpoints.md#eth-gettransactionbyhash)
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- [`eth_getTransactionByBlockNumberAndIndex`](./../api/json-rpc/endpoints.html#eth-gettransactionbyblockhashandindex)
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- [`eth_sendTransaction`](./../api/json-rpc/endpoints.md#eth-sendtransaction)
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## Next {hide}
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Learn how to deploy a Solidity smart contract on Ethermint using [Truffle](./../guides/truffle.md) {hide}
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