Merge pull request #2822 from poanetwork/vb-estimated-address-count

Estimated address count on the main page

CHANGELOG.md

@@ -4,6 +4,7 @@
 - [#2787](https://github.com/poanetwork/blockscout/pull/2787) - async fetching of address counters
 - [#2791](https://github.com/poanetwork/blockscout/pull/2791) - add ipc client
 - [#2449](https://github.com/poanetwork/blockscout/pull/2449) - add ability to send notification events through postgres notify
+- [#2822](https://github.com/poanetwork/blockscout/pull/2822) - Estimated address count on the main page, if cache is empty
 
 ### Fixes
 - [#2830](https://github.com/poanetwork/blockscout/pull/2830) - Fix wrong color of contract icon on xDai chain

apps/block_scout_web/assets/js/pages/token_counters.js

@@ -66,7 +66,7 @@ const elements = {
 
 function loadCounters (store) {
   const $element = $('[data-async-counters]')
-  const path = $element.data().asyncCounters
+  const path = $element.data() && $element.data().asyncCounters
   function fetchCounters () {
     store.dispatch({type: 'START_REQUEST'})
     $.getJSON(path)

apps/block_scout_web/lib/block_scout_web/controllers/address_controller.ex

@@ -59,7 +59,7 @@ defmodule BlockScoutWeb.AddressController do
   def index(conn, _params) do
     render(conn, "index.html",
       current_path: current_path(conn),
-      address_count: Chain.count_addresses_from_cache()
+      address_count: Chain.address_estimated_count()
     )
   end
 

apps/block_scout_web/lib/block_scout_web/controllers/chain_controller.ex

@@ -13,6 +13,7 @@ defmodule BlockScoutWeb.ChainController do
   def show(conn, _params) do
     transaction_estimated_count = Chain.transaction_estimated_count()
     block_count = Chain.block_estimated_count()
+    address_count = Chain.address_estimated_count()
 
     market_cap_calculation =
       case Application.get_env(:explorer, :supply) do
@@ -28,7 +29,7 @@ defmodule BlockScoutWeb.ChainController do
     render(
       conn,
       "show.html",
-      address_count: Chain.count_addresses_from_cache(),
+      address_count: address_count,
       average_block_time: AverageBlockTime.average_block_time(),
       exchange_rate: exchange_rate,
       chart_data_path: market_history_chart_path(conn, :show),

apps/block_scout_web/lib/block_scout_web/notifier.ex

@@ -14,7 +14,7 @@ defmodule BlockScoutWeb.Notifier do
   alias Phoenix.View
 
   def handle_event({:chain_event, :addresses, type, addresses}) when type in [:realtime, :on_demand] do
-    Endpoint.broadcast("addresses:new_address", "count", %{count: Chain.count_addresses_from_cache()})
+    Endpoint.broadcast("addresses:new_address", "count", %{count: Chain.address_estimated_count()})
 
     addresses
     |> Stream.reject(fn %Address{fetched_coin_balance: fetched_coin_balance} -> is_nil(fetched_coin_balance) end)

apps/explorer/lib/explorer/chain.ex

@@ -122,11 +122,21 @@ defmodule Explorer.Chain do
   end
 
   @doc """
-  Gets from the cache the count of all `t:Explorer.Chain.Address.t/0`'s
+  Estimated count of `t:Explorer.Chain.Address.t/0`.
+
+  Estimated count of addresses.
   """
-  @spec count_addresses_from_cache :: non_neg_integer()
-  def count_addresses_from_cache do
-    AddressesCounter.fetch()
+  @spec address_estimated_count() :: non_neg_integer()
+  def address_estimated_count do
+    cached_value = AddressesCounter.fetch()
+
+    if is_nil(cached_value) do
+      %Postgrex.Result{rows: [[count]]} = Repo.query!("SELECT reltuples FROM pg_class WHERE relname = 'addresses';")
+
+      count
+    else
+      cached_value
+    end
   end
 
   @doc """

apps/explorer/test/explorer/chain_test.exs

@@ -51,7 +51,7 @@ defmodule Explorer.ChainTest do
     end
   end
 
-  describe "count_addresses_from_cache/0" do
+  describe "address_estimated_count/0" do
     test "returns the number of all addresses" do
       insert(:address, fetched_coin_balance: 0)
       insert(:address, fetched_coin_balance: 1)
@@ -60,7 +60,7 @@ defmodule Explorer.ChainTest do
       start_supervised!(AddressesCounter)
       AddressesCounter.consolidate()
 
-      addresses_with_balance = Chain.count_addresses_from_cache()
+      addresses_with_balance = Chain.address_estimated_count()
 
       assert is_integer(addresses_with_balance)
       assert addresses_with_balance == 3