Query past block event using LCD's txs endpoint instead of fetching block from RPC to speed up indexing.

[y-pakorn]

By using /txs endpoint on LCD we can directly query transaction that has specific event without need to query every past block from RPC.

- handler: handleEvent
  kind: cosmos/EventHandler
  filter:
    type: execute
    messageFilter:
      type: "/cosmwasm.wasm.v1.MsgExecuteContract"
      contractCall:
        contract: "juno1v99ehkuetkpf0yxdry8ce92yeqaeaa7lyxr2aagkesrw67wcsn8qxpxay0"

Filter above with start block at 3062001 can be translated to
lcd.endpoint/cosmos/tx/v1beta1/txs?events=message.action=/cosmwasm.wasm.v1.MsgExecuteContract&events=execute._contract_address=juno1v99ehkuetkpf0yxdry8ce92yeqaeaa7lyxr2aagkesrw67wcsn8qxpxay0&events=tx.height>=3062001

[stwiname]

Hi @y-pakorn, thanks for your suggestion, we will do some more investigation into this, it does seem like a good idea but may not be particularly scalable if there are handlers for multiple contracts.

We do already have a dictionary solution that we know scales well for this use case. You can read more about them here https://doc.subquery.network/academy/tutorials_examples/dictionary/

We have dictionaries running for various cosmos networks, including Juno https://explorer.subquery.network/subquery/subquery/cosmos-juno-dictionary

[y-pakorn]

Oh, I forgot that the dictionary could be used! Thanks! By the way, the key is to fetch txs based on events using LCD capabilities, which could be great for the network that doesn't have the dictionary, such as testnet or local network.