Store l2 transactions count in the batch table

apps/block_scout_web/lib/block_scout_web/views/api/v2/zkevm_view.ex

@@ -1,11 +1,6 @@
 defmodule BlockScoutWeb.API.V2.ZkevmView do
   use BlockScoutWeb, :view
 
-  import Ecto.Query, only: [from: 2]
-
-  alias Explorer.Chain.ZkevmBatchTxn
-  alias Explorer.Repo
-
   def render("zkevm_batch.json", %{batch: batch}) do
     sequence_tx_hash =
       if not is_nil(batch.sequence_transaction) do
@@ -64,19 +59,7 @@ defmodule BlockScoutWeb.API.V2.ZkevmView do
   end
 
   defp render_zkevm_batches(batches) do
-    batches
-    |> Enum.map(fn batch ->
-      Task.async(fn ->
-        tx_count =
-          Repo.replica().aggregate(
-            from(
-              t in ZkevmBatchTxn,
-              where: t.batch_number == ^batch.number
-            ),
-            :count,
-            timeout: :infinity
-          )
-
+    Enum.map(batches, fn batch ->
       sequence_tx_hash =
         if not is_nil(batch.sequence_transaction) do
           batch.sequence_transaction.hash
@@ -85,12 +68,9 @@ defmodule BlockScoutWeb.API.V2.ZkevmView do
       %{
         "number" => batch.number,
         "timestamp" => batch.timestamp,
-          "tx_count" => tx_count,
+        "tx_count" => batch.l2_transactions_count,
         "sequence_tx_hash" => sequence_tx_hash
       }
     end)
-    end)
-    |> Task.yield_many(:infinity)
-    |> Enum.map(fn {_task, {:ok, item}} -> item end)
   end
 end

apps/explorer/lib/explorer/chain/import/runner/zkevm_txn_batches.ex

@@ -85,6 +85,7 @@ defmodule Explorer.Chain.Import.Runner.ZkevmTxnBatches do
         set: [
           # don't update `number` as it is a primary key and used for the conflict target
           timestamp: fragment("EXCLUDED.timestamp"),
+          l2_transactions_count: fragment("EXCLUDED.l2_transactions_count"),
           global_exit_root: fragment("EXCLUDED.global_exit_root"),
           acc_input_hash: fragment("EXCLUDED.acc_input_hash"),
           state_root: fragment("EXCLUDED.state_root"),
@@ -96,8 +97,9 @@ defmodule Explorer.Chain.Import.Runner.ZkevmTxnBatches do
       ],
       where:
         fragment(
-          "(EXCLUDED.timestamp, EXCLUDED.global_exit_root, EXCLUDED.acc_input_hash, EXCLUDED.state_root, EXCLUDED.sequence_id, EXCLUDED.verify_id) IS DISTINCT FROM (?, ?, ?, ?, ?, ?)",
+          "(EXCLUDED.timestamp, EXCLUDED.l2_transactions_count, EXCLUDED.global_exit_root, EXCLUDED.acc_input_hash, EXCLUDED.state_root, EXCLUDED.sequence_id, EXCLUDED.verify_id) IS DISTINCT FROM (?, ?, ?, ?, ?, ?, ?)",
           tb.timestamp,
+          tb.l2_transactions_count,
           tb.global_exit_root,
           tb.acc_input_hash,
           tb.state_root,

apps/explorer/lib/explorer/chain/zkevm_txn_batch.ex

@@ -7,11 +7,12 @@ defmodule Explorer.Chain.ZkevmTxnBatch do
 
   @optional_attrs ~w(sequence_id verify_id)a
 
-  @required_attrs ~w(number timestamp global_exit_root acc_input_hash state_root)a
+  @required_attrs ~w(number timestamp l2_transactions_count global_exit_root acc_input_hash state_root)a
 
   @type t :: %__MODULE__{
           number: non_neg_integer(),
           timestamp: DateTime.t(),
+          l2_transactions_count: non_neg_integer(),
           global_exit_root: Hash.t(),
           acc_input_hash: Hash.t(),
           state_root: Hash.t(),
@@ -25,6 +26,7 @@ defmodule Explorer.Chain.ZkevmTxnBatch do
   @primary_key {:number, :integer, autogenerate: false}
   schema "zkevm_transaction_batches" do
     field(:timestamp, :utc_datetime_usec)
+    field(:l2_transactions_count, :integer)
     field(:global_exit_root, Hash.Full)
     field(:acc_input_hash, Hash.Full)
     field(:state_root, Hash.Full)

apps/explorer/priv/repo/migrations/20230420110800_create_zkevm_tables.exs

@@ -14,6 +14,7 @@ defmodule Explorer.Repo.Migrations.CreateZkevmTables do
     create table(:zkevm_transaction_batches, primary_key: false) do
       add(:number, :integer, null: false, primary_key: true)
       add(:timestamp, :"timestamp without time zone", null: false)
+      add(:l2_transactions_count, :integer, null: false)
       add(:global_exit_root, :bytea, null: false)
       add(:acc_input_hash, :bytea, null: false)
       add(:state_root, :bytea, null: false)

apps/indexer/lib/indexer/fetcher/zkevm_txn_batch.ex

@@ -262,16 +262,6 @@ defmodule Indexer.Fetcher.ZkevmTxnBatch do
           |> get_tx_hash("verifyBatchTxHash")
           |> handle_tx_hash(hash_to_id, next_id, l1_txs, true)
 
-        batch = %{
-          number: number,
-          timestamp: timestamp,
-          global_exit_root: global_exit_root,
-          acc_input_hash: acc_input_hash,
-          state_root: state_root,
-          sequence_id: sequence_id,
-          verify_id: verify_id
-        }
-
         l2_txs_append =
           l2_transaction_hashes
           |> Kernel.||([])
@@ -282,6 +272,17 @@ defmodule Indexer.Fetcher.ZkevmTxnBatch do
             }
           end)
 
+        batch = %{
+          number: number,
+          timestamp: timestamp,
+          l2_transactions_count: Enum.count(l2_txs_append),
+          global_exit_root: global_exit_root,
+          acc_input_hash: acc_input_hash,
+          state_root: state_root,
+          sequence_id: sequence_id,
+          verify_id: verify_id
+        }
+
         {[batch | batches], l2_txs ++ l2_txs_append, l1_txs, next_id, hash_to_id}
       end)