perf: Improve performance of token page transfers tab (#9809)

* Improve performance of token page transfers tab

* mix format

* Separate index creation and deletion to defferent migrations

* Rename migration

apps/explorer/lib/explorer/graphql.ex

@@ -93,7 +93,7 @@ defmodule Explorer.GraphQL do
       tt in TokenTransfer,
       inner_join: t in assoc(tt, :transaction),
       where: tt.token_contract_address_hash == ^token_contract_address_hash,
-      order_by: [desc: tt.block_number],
+      order_by: [desc: tt.block_number, desc: tt.log_index],
       select: tt
     )
   end

apps/explorer/priv/repo/migrations/20240403151125_enhance_index_for_token_transfers_list.exs

@@ -0,0 +1,11 @@
+defmodule Explorer.Repo.Migrations.EnhanceIndexForTokenTransfersList do
+  use Ecto.Migration
+  @disable_ddl_transaction true
+  @disable_migration_lock true
+
+  def change do
+    create_if_not_exists(
+      index(:token_transfers, ["token_contract_address_hash, block_number DESC, log_index DESC"], concurrently: true)
+    )
+  end
+end

apps/explorer/priv/repo/migrations/20240403151126_drop_outdated_index_for_token_transfers_list.exs

@@ -0,0 +1,9 @@
+defmodule Explorer.Repo.Migrations.DropOutdatedIndexForTokenTransfersList do
+  use Ecto.Migration
+  @disable_ddl_transaction true
+  @disable_migration_lock true
+
+  def change do
+    drop_if_exists(index(:token_transfers, [:token_contract_address_hash, :block_number], concurrently: true))
+  end
+end