Gradual migration support for call_has_call_type, call_has_input, and create_has_init

Fixes #1112

apps/explorer/priv/repo/migrations/20181108205650_additional_internal_transaction_constraints.exs

@@ -1,10 +1,37 @@
 defmodule Explorer.Repo.Migrations.AdditionalInternalTransactionConstraints do
+  @moduledoc """
+  Use `priv/repo/migrations/scripts/20181108205650_additional_internal_transaction_constraints.sql` to migrate data and
+  validate constraint.
+
+  ```sh
+  mix ecto.migrate
+  psql -d $DATABASE -a -f priv/repo/migrations/scripts/20181108205650_additional_internal_transaction_constraints.sql
+  ```
+  """
+
   use Ecto.Migration
 
   def up do
-    create(constraint(:internal_transactions, :call_has_call_type, check: "type != 'call' OR call_type IS NOT NULL"))
-    create(constraint(:internal_transactions, :call_has_input, check: "type != 'call' OR input IS NOT NULL"))
-    create(constraint(:internal_transactions, :create_has_init, check: "type != 'create' OR init IS NOT NULL"))
+    execute("""
+    ALTER TABLE internal_transactions
+    ADD CONSTRAINT call_has_call_type
+    CHECK (type != 'call' OR call_type IS NOT NULL)
+    NOT VALID
+    """)
+
+    execute("""
+    ALTER TABLE internal_transactions
+    ADD CONSTRAINT call_has_input
+    CHECK (type != 'call' OR input IS NOT NULL)
+    NOT VALID
+    """)
+
+    execute("""
+    ALTER TABLE internal_transactions
+    ADD CONSTRAINT create_has_init
+    CHECK (type != 'create' OR init IS NOT NULL)
+    NOT VALID
+    """)
   end
 
   def down do

apps/explorer/priv/repo/migrations/scripts/20181108205650_additional_internal_transaction_constraints.sql

@@ -0,0 +1,80 @@
+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_transaction_count integer;
+   deleted_internal_transaction_count integer;
+   deleted_row_count integer;
+BEGIN
+  DROP TABLE IF EXISTS transactions_with_deprecated_internal_transactions;
+  -- CREATES TEMP TABLE TO STORE DATA TO BE UPDATED
+  CREATE TEMP TABLE transactions_with_deprecated_internal_transactions(
+    hash bytea NOT NULL,
+    row_number integer
+  );
+  INSERT INTO transactions_with_deprecated_internal_transactions
+  SELECT DISTINCT ON (transaction_hash)
+    transaction_hash,
+    ROW_NUMBER () OVER ()
+  FROM internal_transactions
+  WHERE
+    -- call_has_call_type CONSTRAINT
+    (type = 'call' AND call_type IS NULL) OR
+    -- call_has_input CONSTRAINT
+    (type = 'call' AND input IS NULL) OR
+    -- create_has_init CONSTRAINT
+    (type = 'create' AND init is NULL)
+  ORDER BY transaction_hash DESC;
+
+  max_row_number := (SELECT MAX(row_number) FROM transactions_with_deprecated_internal_transactions);
+  RAISE NOTICE '% transactions 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 '-> transactions with deprecated internal transactions % to % to be updated', iterator, next_iterator - 1;
+
+    UPDATE transactions
+    SET internal_transactions_indexed_at = NULL,
+        error = NULL
+    FROM transactions_with_deprecated_internal_transactions
+    WHERE transactions.hash = transactions_with_deprecated_internal_transactions.hash AND
+          transactions_with_deprecated_internal_transactions.row_number < next_iterator;
+
+    GET DIAGNOSTICS updated_transaction_count = ROW_COUNT;
+
+    RAISE NOTICE '-> % transactions updated to refetch internal transactions', updated_transaction_count;
+
+    DELETE FROM internal_transactions
+    USING transactions_with_deprecated_internal_transactions
+    WHERE internal_transactions.transaction_hash = transactions_with_deprecated_internal_transactions.hash AND
+          transactions_with_deprecated_internal_transactions.row_number < next_iterator;
+
+    GET DIAGNOSTICS deleted_internal_transaction_count = ROW_COUNT;
+
+    RAISE NOTICE  '-> % internal transactions deleted', deleted_internal_transaction_count;
+
+    DELETE FROM transactions_with_deprecated_internal_transactions
+    WHERE row_number < next_iterator;
+
+    GET DIAGNOSTICS deleted_row_count = ROW_COUNT;
+
+    ASSERT updated_transaction_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 deprecated internal transactions will be refetched.  Validating constraints.';
+
+  ALTER TABLE internal_transactions VALIDATE CONSTRAINT call_has_call_type;
+  ALTER TABLE internal_transactions VALIDATE CONSTRAINT call_has_input;
+  ALTER TABLE internal_transactions VALIDATE CONSTRAINT create_has_init;
+END $$;