Accessing older blocks from Geth: Returned error: missing trie node 94d34

Question

When my Nodejs script uses web3 to query a geth node running in a private Ethereum network for an older block, I encounter the error

UnhandledPromiseRejectionWarning: Error: Returned error: missing trie node 94d3409b537ed93710c0b20e3f116e953c8284d251219f6a60de0da03207b0b8 (path )

geth Geth/v1.8.13-unstable-2e0391ea/linux-amd64/go1.10.3 has been started using the syncmode="full" parameter and it can be seen synchronizing all the blocks from the very first block

--networkid 1366 --cache 512 --syncmode="full" --port 30303 --maxpeers 50 --rpc --rpcaddr "0.0.0.0" --rpcapi "eth,personal,web3,net" --bootnodes enode://id@ip:port

Question: Is this because --trie-cache-gens is set to it's default value of 120?

What is a trie node generations?

If we need to access the entire blockchain history, what value should we set it to? Or is there another setting to adjust to allow this?

Answer 1

You will need to add the --gcmode=archive option to access arbitrary historical states. This will require a resync of the chainstate (although I think there's a way to get it to do that without downloading everything over again, and it'll prompt you for it when you first try and apply the option)