Solana: pre/postTokenBalances accountIndex doesnt correspond to accountKeys Index

Solana Transaction Error: Problem with method ‘getTransaction’

As an experienced developer working with the Solana blockchain, I am here to help you troubleshoot and resolve the transaction error issue in your account ‘preTokenBalances’. In this article, we will dig deeper into the issue and provide solutions to resolve it.

Issue Overview

The error message usually looks like this:

Error: getTransaction method returns invalid balances before token

or

Error: Mismatched account index in account index for TokenBalances 2 does not match account key index 3

This error occurs when the ‘accountIndex’ of the account ‘preTokenBalances’ does not match the expected account key ‘accountKeyIndex’.

Causes of the issue

There are several reasons why this can happen:

• Incorrect account index: Make sure that the “accountIndex” in the “preTokenBalances” data is set correctly and matches the expected account index for each account.

• Invalid account keys: Make sure that all accounts in your “preTokenBalances” have valid account keys. Account keys must be unique for each account and their indexes must match the order of the account key when accessed (e.g., “accountIndex 1”, “accountKeyIndex 0”, etc.).

• Incorrect balance information: Make sure that your balance information is accurate and up to date, as any discrepancy can cause this issue.

Solutions

To resolve this error, do the following:

Step 1: Check the account index and key order

Check the following:

• Are all account indices correct (e.g. ‘2’, ‘3’, etc.)?

• Do all account keys match when accessed in the expected order (accountKeyIndex 0, accountKeyIndex 1, etc.)?

Step 2: Check balance details

Check your balance information to ensure it is accurate and consistent. This may include checking the balances for each account in your ‘preTokenBalances’ table.

Step 3: Adjust account index values ​​if necessary

If you suspect a mismatch between the accountIndex and accountKeyIndex values, update them accordingly:

• For example, if your preTokenBalances table contains accounts with indexes 2 and 3:

for token balances: [
{
accountIndex: 2,
mint:...
},
{
accountIndex: 3,
mint:...
}
]

You can then use the corrected accountKeyIndex when accessing these accounts (e.g. by using accountKeyIndex 0 or accountKeyIndex 1).

Step 4: Ensure consistency between balances and indices

Check that your balance data is consistent with the index in question. If you have multiple accounts with the same name, make sure their balances are updated correctly.

Example Usage

Suppose we have an account with a balance of “1 Solana (SOL)” in our “preTokenBalances” table:

{
"accountIndex": 2,
"mint":...
}

We can update the index and key order of this account as follows:

// Update the account index to match the expected account key order
pourTokenBalances[0].accountKeyIndex = 1;
// Check that the balance data is consistent with the new index
if (preTokenBalances[0].balance == SOL) {
console.log("Balance updated successfully");
} other {
console.error("Balance update failed");
}

By following these steps and checking the account index and key order, you should be able to resolve the “getTransaction” method error in your Solana transactions.