Idid a transaction one week back with 1 sat/vbyte. Still not confirmed. How can I rebroadcast it from core wallet because some nodes are purging low fee transactions.
Bitcoin Core will automatically rebroadcast transactions for you periodically. Rebroadcasting occurs randomly between 12 and 24 hours from the previous rebroadcast or wallet startup.
To manually rebroadcast, you will need to get the raw transaction and resend it using
sendrawtransaction. You can get the raw transaction by right clicking the transaction in the transactions list and choosing "Copy raw transaction". Then open the debug console via Window > Console and enter
sendrawtransaction <tx> where
<tx> is replaced with the copied raw transaction.