fix: `GAS_PRICE_ORACLE_NUM_OF_BLOCKS` calculation (#9943)

apps/explorer/lib/explorer/chain/cache/gas_price_oracle.ex

@@ -12,6 +12,7 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
 
   alias Explorer.Chain.{Block, Wei}
 
+  alias Explorer.Chain.Cache.BlockNumber
   alias Explorer.Counters.AverageBlockTime
   alias Explorer.{Market, Repo}
   alias Timex.Duration
@@ -81,12 +82,16 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
 
     acc = get_gas_prices_acc()
 
-    from_block =
+    from_block_actual = BlockNumber.get_max() - num_of_blocks
+
+    from_block_acc =
       case acc do
         [%{block_number: from_block} | _] -> from_block
         _ -> -1
       end
 
+    from_block_query = max(from_block_acc, from_block_actual)
+
     average_block_time =
       case AverageBlockTime.average_block_time() do
         {:error, _} -> nil
@@ -99,7 +104,7 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
         left_join: transaction in assoc(block, :transactions),
         where: block.consensus == true,
         where: is_nil(transaction.gas_price) or transaction.gas_price > ^0,
-        where: transaction.block_number > ^from_block,
+        where: transaction.block_number > ^from_block_query,
         group_by: transaction.block_number,
         order_by: [desc: transaction.block_number],
         select: %{
@@ -164,11 +169,10 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
               block.timestamp - transaction.earliest_processing_start,
               ^(average_block_time && average_block_time * fast_time_coefficient())
             )
-        },
-        limit: ^num_of_blocks
+        }
       )
 
-    new_acc = fee_query |> Repo.all(timeout: :infinity) |> merge_gas_prices(acc, num_of_blocks)
+    new_acc = fee_query |> Repo.all(timeout: :infinity) |> merge_gas_prices(acc, from_block_actual)
 
     gas_prices = new_acc |> process_fee_data_from_db()
 
@@ -179,7 +183,7 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
       {{:error, error}, get_gas_prices_acc()}
   end
 
-  defp merge_gas_prices(new, acc, acc_size), do: Enum.take(new ++ acc, acc_size)
+  defp merge_gas_prices(new, acc, from_block), do: Enum.take_while(new ++ acc, &(&1.block_number > from_block))
 
   defp process_fee_data_from_db([]) do
     %{
@@ -259,12 +263,13 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
       base_fee: base_fee |> format_wei(),
       priority_fee: base_fee && priority_fee && priority_fee |> Decimal.new() |> Wei.from(:wei) |> format_wei(),
       priority_fee_wei: base_fee && priority_fee && priority_fee |> Decimal.new() |> Decimal.round(),
-      wei: fee |> Wei.to(:wei) |> Decimal.round()
+      wei: fee && fee |> Wei.to(:wei) |> Decimal.round()
     }
   end
 
   defp fiat_fee(fee, exchange_rate) do
-    exchange_rate.usd_value &&
+    fee &&
+      exchange_rate.usd_value &&
       fee
       |> Wei.to(:ether)
       |> Decimal.mult(exchange_rate.usd_value)
@@ -276,6 +281,8 @@ defmodule Explorer.Chain.Cache.GasPriceOracle do
     priority |> Wei.from(:wei) |> Wei.sum(base_fee)
   end
 
+  defp gas_price(nil), do: nil
+
   defp gas_price(value) do
     value |> Wei.from(:wei)
   end

apps/explorer/test/explorer/chain/cache/gas_price_oracle_test.exs

@@ -460,5 +460,76 @@ defmodule Explorer.Chain.Cache.GasPriceOracleTest do
                 }
               }, _} = GasPriceOracle.get_average_gas_price(3, 35, 60, 90)
     end
+
+    test "does not take into account old transaction even if there is no new ones" do
+      gas_price_oracle_old_env = Application.get_env(:explorer, GasPriceOracle)
+
+      Application.put_env(:explorer, GasPriceOracle, num_of_blocks: 3)
+
+      on_exit(fn ->
+        Application.put_env(:explorer, GasPriceOracle, gas_price_oracle_old_env)
+      end)
+
+      block1 = insert(:block, number: 1)
+      block2 = insert(:block, number: 2)
+      block3 = insert(:block, number: 3)
+      block4 = insert(:block, number: 4)
+      block5 = insert(:block, number: 5)
+
+      :transaction
+      |> insert(
+        status: :ok,
+        block_hash: block1.hash,
+        block_number: block1.number,
+        cumulative_gas_used: 884_322,
+        gas_used: 106_025,
+        index: 0,
+        gas_price: 1_000_000_000,
+        max_priority_fee_per_gas: 1_000_000_000,
+        max_fee_per_gas: 1_000_000_000
+      )
+
+      :transaction
+      |> insert(
+        status: :ok,
+        block_hash: block2.hash,
+        block_number: block2.number,
+        cumulative_gas_used: 884_322,
+        gas_used: 106_025,
+        index: 0,
+        gas_price: 1_000_000_000,
+        max_priority_fee_per_gas: 1_000_000_000,
+        max_fee_per_gas: 1_000_000_000
+      )
+
+      :transaction
+      |> build(
+        status: :ok,
+        block_hash: block3.hash,
+        block_number: block3.number,
+        gas_price: 0,
+        cumulative_gas_used: 884_322
+      )
+
+      :transaction
+      |> build(
+        status: :ok,
+        block_hash: block4.hash,
+        block_number: block4.number,
+        gas_price: 0,
+        cumulative_gas_used: 884_322
+      )
+
+      :transaction
+      |> build(
+        status: :ok,
+        block_hash: block5.hash,
+        block_number: block5.number,
+        gas_price: 0,
+        cumulative_gas_used: 884_322
+      )
+
+      assert {{:ok, %{average: nil, fast: nil, slow: nil}}, _} = GasPriceOracle.get_average_gas_price(3, 35, 60, 90)
+    end
   end
 end