fetch last not empty coin balance records

apps/explorer/lib/explorer/chain.ex

@@ -66,6 +66,8 @@ defmodule Explorer.Chain do
 
   @max_incoming_transactions_count 10_000
 
+  @coin_balance_records_count 90
+
   @typedoc """
   The name of an association on the `t:Ecto.Schema.t/0`
   """
@@ -2976,7 +2978,7 @@ defmodule Explorer.Chain do
   @spec address_to_balances_by_day(Hash.Address.t()) :: [balance_by_day]
   def address_to_balances_by_day(address_hash) do
     address_hash
-    |> CoinBalance.balances_by_day()
+    |> CoinBalance.balances_by_day(@coin_balance_records_count)
     |> Repo.all()
     |> normalize_balances_by_day()
   end

apps/explorer/lib/explorer/chain/address/coin_balance.ex

@@ -89,14 +89,14 @@ defmodule Explorer.Chain.Address.CoinBalance do
   Builds an `Ecto.Query` to fetch a series of balances by day for the given account. Each element in the series
   corresponds to the maximum balance in that day. Only the last 90 days of data are used.
   """
-  def balances_by_day(address_hash) do
+  def balances_by_day(address_hash, number \\ 60) do
     CoinBalance
     |> join(:inner, [cb], b in Block, on: cb.block_number == b.number)
     |> where([cb], cb.address_hash == ^address_hash)
-    |> where([cb, b], b.timestamp >= fragment("date_trunc('day', now()) - interval '90 days'"))
     |> group_by([cb, b], fragment("date_trunc('day', ?)", b.timestamp))
     |> order_by([cb, b], fragment("date_trunc('day', ?)", b.timestamp))
     |> select([cb, b], %{date: type(fragment("date_trunc('day', ?)", b.timestamp), :date), value: max(cb.value)})
+    |> limit(^number)
   end
 
   def changeset(%__MODULE__{} = balance, params) do

apps/explorer/test/explorer/chain/address/coin_balance_test.exs

@@ -2,8 +2,8 @@ defmodule Explorer.Chain.Address.CoinBalanceTest do
   use Explorer.DataCase
 
   alias Ecto.Changeset
-  alias Explorer.Chain.{Block, Wei}
   alias Explorer.Chain.Address.CoinBalance
+  alias Explorer.Chain.{Block, Wei}
   alias Explorer.PagingOptions
 
   describe "changeset/2" do
@@ -225,7 +225,7 @@ defmodule Explorer.Chain.Address.CoinBalanceTest do
 
       assert(length(result) == 1)
 
-      value = List.first(result) |> Map.get(:value)
+      value = result |> List.first() |> Map.get(:value)
 
       assert(value == Wei.from(Decimal.new(3000), :wei))
     end
@@ -247,7 +247,7 @@ defmodule Explorer.Chain.Address.CoinBalanceTest do
 
       assert(length(result) == 1)
 
-      value = List.first(result) |> Map.get(:value)
+      value = result |> List.first() |> Map.get(:value)
 
       assert(value == Wei.from(Decimal.new(3000), :wei))
     end
@@ -269,9 +269,29 @@ defmodule Explorer.Chain.Address.CoinBalanceTest do
 
       assert(length(result) == 1)
 
-      value = List.first(result) |> Map.get(:value)
+      value = result |> List.first() |> Map.get(:value)
 
       assert(value == Wei.from(Decimal.new(3000), :wei))
     end
+
+    test "fetches old records" do
+      address = insert(:address)
+      noon = Timex.now() |> Timex.beginning_of_day() |> Timex.set(hour: 12)
+      block = insert(:block, timestamp: noon)
+      old_block = insert(:block, timestamp: Timex.shift(noon, days: -700))
+      insert(:fetched_balance, address_hash: address.hash, value: 1000, block_number: block.number)
+      insert(:fetched_balance, address_hash: address.hash, value: 2000, block_number: old_block.number)
+
+      result =
+        address.hash
+        |> CoinBalance.balances_by_day()
+        |> Repo.all()
+
+      assert(length(result) == 2)
+
+      value = result |> List.first() |> Map.get(:value)
+
+      assert(value == Wei.from(Decimal.new(2000), :wei))
+    end
   end
 end