Solana Transaction Error: getTransaction Method Issue

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

Issue Overview

The error message usually looks like this:

Error: getTransaction method returns invalid pre-token balances

or

Error: AccountIndex mismatch in preTokenBalances account index 2 does not match accountKeyIndex 3

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

Causes of the issue

There are several reasons why this could happen:

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

• Invalid account keys

  

  : Make sure 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 data: Make sure your balance data is correct and up-to-date, as any discrepancies can cause this issue.

Solutions

To resolve this error, follow these steps:

Step 1: Check the account index and key order

Verify the following:

• Are all account indexes correct (e.g. 2, 3, etc.)?

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

Step 2: Validate balance data

Recheck your balance data to ensure it is accurate and consistent. This may involve checking the balances for each account in your preTokenBalances array.

Step 3: Adjust account index values ​​if necessary

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

• For example, if your preTokenBalances array contains accounts with indices 2 and 3:

preTokenBalances: [
{
accountIndex: 2,
mint: ...
},
{
accountIndex: 3,
mint: ...
}
]

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

Step 4: Ensure consistency between balances and indices

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

Example Use Case

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

{
"account index": 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
preTokenBalances[0].accountKeyIndex = 1;
// Check if the balance data is consistent with its new index
if (preTokenBalances[0].balance == SOL) {
console.log("Balance updated correctly");
} else {
console.error("Balance update failed");
}

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

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