Patching Unlucky & Duplicate Tx

In the first version of Cronos (v0.6), there was a known issue where transactions were being included in a block even when the block gas limit at the EVM level had already been reached. This led to:

• Some "unlucky" transactions (before block height2693800) are not reflected at the EVM level

• One would observe a few blocks that have >100% of the block gas limit at the EVM level.

• Duplicate transactions

A node host has two ways to obtain a complete database with patched transactions:

1. Start from genesis and perform the necessary steps at each block height

2. Perform a one-off sync from a snapshot

Method 1: Start from Genesis

Step 1. Follow the Cronos Mainnet docs from step 1 to start syncing a node with binaryv0.6.11

Step 2. When you reach blockheight 2693800, the binary should automatically halt. Now run the command fix-unlucky-txto patch unlucky transactions. This patch only works for blocks until blockheight 2693800.

./cronosd fix-unlucky-tx --start-block 1 --end-block 2693800

More information on this command can be found in the release notes of 0.7.1-rc0 https://github.com/crypto-org-chain/cronos/releases/tag/v0.7.1-rc0 And in the patch unlucky tx wiki https://github.com/crypto-org-chain/cronos/wiki/Patch-Unlucky-Tx

Step 3. Verify that the unlucky tx have been patched by checking the following example tx hash 0x435ef379b9ddf226d9fe098ae39d36aed2d03f3c46febd84c48919f1adf1b7fe

curl -X POST 'https://evm.cronos.org' \
-H 'Content-Type: application/json' \
-d '{
    "jsonrpc": "2.0",
    "method": "eth_getTransactionByHash",
    "params": [
        "0x435ef379b9ddf226d9fe098ae39d36aed2d03f3c46febd84c48919f1adf1b7fe"
    ],
    "id": 44
}'

{"jsonrpc":"2.0","id":44,"result":{"blockHash":"0xf0843bf4f40edb41537ef08fe70e192da77fba26eaae31871c63b15a2b9bda81","blockNumber":"0x2925bc","from":"0x1bfcb6b1ee66fe339a9dc452359c4c111cc5ffc0","gas":"0x5d9b18","gasPrice":"0x48c27395000","maxFeePerGas":"0x48c27395000","maxPriorityFeePerGas":"0x48c27395000","hash":"0x435ef379b9ddf226d9fe098ae39d36aed2d03f3c46febd84c48919f1adf1b7fe","input":"0xd931ccbc000000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000050000000000000000000000000000000000000000000000000000000000000bf50000000000000000000000000000000000000000000000000000000002faf0800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000012c00000000000000000000000000000000000000000000000000000000000026de00000000000000000000000000000000000000000000000000000000000005dc","nonce":"0x8b","to":"0xb212ce53ff067ce6e07e3adcd39a362e54c9e534","transactionIndex":"0x1e","value":"0x0","type":"0x2","accessList":[],"chainId":"0x19","v":"0x0","r":"0xf5268b439f80c5294465d70804fe2f731ef87bf54d726ead72772a0162081767","s":"0x292d753ad7e52839c974df0325bd41cb2766d4f1c0ecd5d561d14da05b257d8"}}

Step 4. Run the command reindex-duplicated-tx to patch duplicated transactions. This command works for all blockheights.

./cronosd reindex-duplicated-tx --start-block 1 --end-block 2693800

Step 5. Verify that the duplicate tx have been patched by checking the following example tx hash 0x3941c8a1625163165fb185e934d463743258ee4b0924c5deb690fc836dab839d

curl -X POST 'https://evm.cronos.org' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_getTransactionByHash",
    "params": [
        "0x3941c8a1625163165fb185e934d463743258ee4b0924c5deb690fc836dab839d"
    ],
    "id": 44
}'

{"jsonrpc":"2.0","id":44,"result":{"blockHash":"0x6eca0e692f6cce612a5c52294db0f5c75127dc6feb310b2693bc697fe3797793","blockNumber":"0x28c3ed","from":"0xdb8befa2f810662316e298f387c943e57b377260","gas":"0x7a120","gasPrice":"0x4a36fb03800","hash":"0x3941c8a1625163165fb185e934d463743258ee4b0924c5deb690fc836dab839d","input":"0x54d2f242","nonce":"0x30","to":"0xc6494099716abe3d95db5a97e5a7fc5ae7e7caba","transactionIndex":"0x0","value":"0x0","type":"0x0","v":"0x55","r":"0xea07319d8a7666afd8ad4970d7f11e2135c9b71719fc34b69995c110beeb84f4","s":"0x2f4f5aa3a822121ee65aa879ff50a2a4504d2f7575d404f1d22685e06d86e07b"}}

Step 6. After the unlucky has been patched, follow the Upgrade notes on performing upgrades until the node is synced to the current block height.

You can print out which blocks will need re-indexing by adding the --print-txs argument. Bear in mind that this won't actually reindex the block, but rather just print.

Method 2: Start from a latest patched snapshot

Alternatively, you can do a one-off sync, if you start with the most recent snapshot, that already includes patched transactions (after November).

Get the latest snapshot with patched data on S3 here