Separate schema and data migration for EIP-6

Fixes #1109

Use `NOT VALID` on constraint and don't put data updates in schema
migration.  Instead, migrate data using script based on @amandasposito's
scripts.

apps/explorer/lib/explorer/chain/internal_transaction/type.ex

@@ -38,6 +38,13 @@ defmodule Explorer.Chain.InternalTransaction.Type do
       iex> Explorer.Chain.InternalTransaction.Type.cast("selfdestruct")
       {:ok, :selfdestruct}
 
+  Deprecated values are not allowed for incoming data.
+
+      iex> Explorer.Chain.InternalTransaction.Type.cast(:suicide)
+      :error
+      iex> Explorer.Chain.InternalTransaction.Type.cast("suicide")
+      :error
+
   Unsupported `String.t` return an `:error`.
 
       iex> Explorer.Chain.InternalTransaction.Type.cast("hard-fork")
@@ -65,6 +72,11 @@ defmodule Explorer.Chain.InternalTransaction.Type do
       iex> Explorer.Chain.InternalTransaction.Type.dump(:selfdestruct)
       {:ok, "selfdestruct"}
 
+  Deprecated values are not allowed to be dumped to the database as old values should only be read, not written.
+
+      iex> Explorer.Chain.InternalTransaction.Type.dump(:suicide)
+      :error
+
   Other atoms return an error
 
       iex> Explorer.Chain.InternalTransaction.Type.dump(:other)
@@ -91,6 +103,11 @@ defmodule Explorer.Chain.InternalTransaction.Type do
       iex> Explorer.Chain.InternalTransaction.Type.load("selfdestruct")
       {:ok, :selfdestruct}
 
+  Converts deprecated value on load to the corresponding `t:t/0`.
+
+      iex> Explorer.Chain.InternalTransaction.Type.load("suicide")
+      {:ok, :selfdestruct}
+
   Other `t:String.t/0` return `:error`
 
       iex> Explorer.Chain.InternalTransaction.Type.load("other")
@@ -103,6 +120,8 @@ defmodule Explorer.Chain.InternalTransaction.Type do
   def load("create"), do: {:ok, :create}
   def load("reward"), do: {:ok, :reward}
   def load("selfdestruct"), do: {:ok, :selfdestruct}
+  # deprecated
+  def load("suicide"), do: {:ok, :selfdestruct}
   def load(_), do: :error
 
   @doc """

apps/explorer/priv/repo/migrations/20181107164103_eip6.exs

@@ -1,28 +1,31 @@
 defmodule Explorer.Repo.Migrations.EIP6 do
+  @moduledoc """
+  Use `priv/repo/migrations/scripts/20181107164103_eip6.sql` to migrate data and validate constraint.
+
+  ```sh
+  mix ecto.migrate
+  psql -d $DATABASE -a -f priv/repo/migrations/scripts/20181107164103_eip6.sql
+  ```
+  """
+
   use Ecto.Migration
 
   def up do
     execute("ALTER TABLE internal_transactions DROP CONSTRAINT suicide_has_from_and_to_address_hashes")
 
-    execute("UPDATE internal_transactions SET type = 'selfdestruct' WHERE type = 'suicide'")
-
-    create(
-      constraint(
-        :internal_transactions,
-        :selfdestruct_has_from_and_to_address_hashes,
-        check: """
-        type != 'selfdestruct' OR
-        (from_address_hash IS NOT NULL AND gas IS NULL AND to_address_hash IS NOT NULL)
-        """
-      )
-    )
+    # `NOT VALID` skips checking pre-existing rows. Use `priv/repo/migrations/scripts/20181107164103_eip6.sql` to
+    # migrate data and validate constraints
+    execute("""
+    ALTER TABLE internal_transactions
+    ADD CONSTRAINT selfdestruct_has_from_and_to_address
+    CHECK (type != 'selfdestruct' OR (from_address_hash IS NOT NULL AND gas IS NULL AND to_address_hash IS NOT NULL))
+    NOT VALID
+    """)
   end
 
   def down do
     execute("ALTER TABLE internal_transactions DROP CONSTRAINT selfdestruct_has_from_and_to_address_hashes")
 
-    execute("UPDATE internal_transactions SET type = 'suicide' WHERE type = 'selfdestruct'")
-
     create(
       constraint(
         :internal_transactions,

apps/explorer/priv/repo/migrations/scripts/20181107164103_eip6.sql

@@ -0,0 +1,64 @@
+DO $$
+DECLARE
+   row_count integer := 1;
+   batch_size  integer := 50000; -- HOW MANY ITEMS WILL BE UPDATED AT TIME
+   iterator  integer := batch_size;
+   max_row_number integer;
+   next_iterator integer;
+   updated_row_count integer;
+   deleted_row_count integer;
+BEGIN
+  DROP TABLE IF EXISTS current_suicide_internal_transactions_temp;
+  -- CREATES TEMP TABLE TO STORE DATA TO BE UPDATED
+  CREATE TEMP TABLE current_suicide_internal_transactions_temp(
+    transaction_hash bytea NOT NULL,
+    index bigint NOT NULL,
+    row_number integer
+  );
+  INSERT INTO current_suicide_internal_transactions_temp
+  SELECT DISTINCT ON (transaction_hash, index)
+    transaction_hash,
+    index,
+    ROW_NUMBER () OVER ()
+  FROM internal_transactions
+  WHERE type = 'suicide'
+  ORDER BY transaction_hash, index DESC;
+
+  max_row_number := (SELECT MAX(row_number) FROM current_suicide_internal_transactions_temp);
+  RAISE NOTICE '% items to be updated', max_row_number + 1;
+
+  -- ITERATES THROUGH THE ITEMS UNTIL THE TEMP TABLE IS EMPTY
+  WHILE iterator <= max_row_number LOOP
+    next_iterator := iterator + batch_size;
+
+    RAISE NOTICE '-> suicide internal transactions % to % to be updated', iterator, next_iterator - 1;
+
+    UPDATE internal_transactions
+    SET type = 'selfdestruct'
+    FROM current_suicide_internal_transactions_temp
+    WHERE internal_transactions.transaction_hash = current_suicide_internal_transactions_temp.transaction_hash AND
+          internal_transactions.index = current_suicide_internal_transactions_temp.index AND
+          current_suicide_internal_transactions_temp.row_number < next_iterator;
+
+    GET DIAGNOSTICS updated_row_count = ROW_COUNT;
+
+    RAISE NOTICE '-> % internal transactions updated from suicide to selfdesruct', updated_row_count;
+
+    DELETE FROM current_suicide_internal_transactions_temp
+    WHERE row_number < next_iterator;
+
+    GET DIAGNOSTICS deleted_row_count = ROW_COUNT;
+
+    ASSERT updated_row_count = deleted_row_count;
+
+    -- COMMITS THE BATCH UPDATES
+    CHECKPOINT;
+
+    -- UPDATES THE COUNTER SO IT DOESN'T TURN INTO AN INFINITE LOOP
+    iterator := next_iterator;
+  END LOOP;
+
+  RAISE NOTICE 'All suicide type internal transactions updated to selfdestruct.  Validating constraint.';
+
+  ALTER TABLE internal_transactions VALIDATE CONSTRAINT selfdestruct_has_from_and_to_address;
+END $$;