In order to create history and statistics, I'm struggling to figure out the best way to implement a lookup system. I'm building a game, and right now, my init for the entrant account looks like this:

        payer = player,
        seeds = [b"entrant", player.key().as_ref(), round.key().as_ref()],
        space = 8 + Entrant::MAXIMUM_SIZE)
    pub entrant: Account<'info, Entrant>,

Since a player can enter more than one round, I'm using both the player key and the round key as the seeds.

However, given the player, I want to be able to somehow lookup all the rounds the player has ever played. I don't want to keep in in one account, as this game can have a lot of rounds and I don't want to run out space.

What would be the best practice in dealing with a situation like this?

2 Answers 2


I think you should use:

seeds = [b"entrant", game.key().as_ref(), player.key().as_ref(), round.key().as_ref()]

And pass the relevant round to the program.

The client can search via getProgramAccounts for the player/game combo.

  • Thanks! I think I was a little unclear. There is only one game, as a one game = one round, so there is no "game" account.
    – web3man
    Commented Jul 27, 2022 at 2:53
  • The issue is, that you need to pass the program all accounts for the transaction. So an on-chain lookup doesn't help much. Since you can just supply a pointer to it an use that. Unless you store a blob of data on-chain which is expensive and limited.
    – Ohad Dahan
    Commented Jul 27, 2022 at 5:54
  • Hmm. That's tough. How would you handle a game that has more players than can fit in an account. Let's say 2000 people participate in a game
    – web3man
    Commented Jul 27, 2022 at 10:57
  • Do you need all 2000 players info in each txn?
    – Ohad Dahan
    Commented Jul 27, 2022 at 14:51
  • 1
    I was able to figure out a different structure for this in the contract where I just check to see individually if the user won each round, and can use the getProgramAccounts on the client. Thank you for the help!
    – web3man
    Commented Jul 27, 2022 at 16:06

You have two main options:

  • iterate through all the possible combinations of seeds for a user. If you know that the current max round is 2000, you can try all possible 2000 entrant addresses and fetch the account there. For huge numbers, this will be tricky.
  • store the player address in the entrant account, and then do a get_program_accounts with the correct offsets for the entrant account type and the user's address

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