What causes Transaction Pool Error?

post by thinguyen on Jul 1, 2021

I am using a Python loops to write many transactions simultaneously. If I do not put sleep() between every iteration, I get error such:

algosdk.error.AlgodHTTPError: {“message”:“TransactionPool.Remember: transaction already in ledger: N6DGJLF4PQEJRW4LBELO562XWX7LUXRCGIQETB5ZTLO2C42BRAJQ”}

Or sometimes even when I add sleep time in between, loop will iterate a few times then the same error happens. What’s the reason behind this? Is it because I can only try to commit 1 transaction into 1 block at a time. And If I try to commit 2 transactions to 1 block, it will generate the same transaction ID which then causes the error?

Thank you

post by tsachi on Jul 2, 2021

All transactions need to be unique to be included in the blockchain. You can add a monotonic growing counter and store it in the notes field in order to do that.

post by mmorselli on Apr 12, 2022

How are those two transactions possible? They are in the same block, having the same sender, same receiver, same amount, and same note.

https://algoexplorer.io/tx/2U5EVSJEO5GRRCVPKLIHE2ZYFORTI6IMRUMDLBUYJPX7BRNJXL2Q

https://algoexplorer.io/tx/4SVYFHD3RDVDG2Q2MVNB34Z6S2BFHVOIF5WC7QFGEVD7MV3B7RHQ

post by fabrice on Apr 13, 2022

These two transactions have a different “first round” (as you can see in “More Information”).