.iter()
        .map(|(_, txid)| txid)
        .collect::<HashSet<_>>();
      for (tx, _) in &block.txdata {
        for input in &tx.input {
          let prev_output = input.previous_output;
          // We don't need coinbase input value
          if prev_output.is_null() {
            continue;
          }
          // We don't need input values from txs earlier in the block, since they'll be added to value_cache
          // when the tx is indexed
          if txids.contains(&prev_output.txid) {
            continue;
          }
          // We don't need input values we already have in our value_cache from earlier blocks
          if value_cache.contains_key(&prev_output) {
            continue;
          }
          // We don't need input values we already have in our outpoint_to_value table from earlier blocks that
          // were committed to db already
          if outpoint_to_value.get(&prev_output.store())?.is_some() {
            continue;
          }
          // We don't know the value of this tx input. Send this outpoint to background thread to be fetched