Switch token_transfers to composite primary key

* Drop id.
* Make (transaaction_hash, log_index) the primary key.

This ports the change from `internal_transactions`.

apps/explorer/lib/explorer/chain.ex

@@ -1967,7 +1967,7 @@ defmodule Explorer.Chain do
         left_join: tf in TokenTransfer,
         on: tf.transaction_hash == l.transaction_hash and tf.log_index == l.index,
         where: l.first_topic == unquote(TokenTransfer.constant()),
-        where: is_nil(tf.id),
+        where: is_nil(tf.transaction_hash) and is_nil(tf.log_index),
         select: t.block_number,
         distinct: t.block_number
       )

apps/explorer/lib/explorer/chain/token_transfer.ex

@@ -62,9 +62,10 @@ defmodule Explorer.Chain.TokenTransfer do
 
   @constant "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
 
+  @primary_key false
   schema "token_transfers" do
     field(:amount, :decimal)
-    field(:log_index, :integer)
+    field(:log_index, :integer, primary_key: true)
     field(:token_id, :decimal)
 
     belongs_to(:from_address, Address, foreign_key: :from_address_hash, references: :hash, type: Hash.Address)
@@ -78,7 +79,12 @@ defmodule Explorer.Chain.TokenTransfer do
       type: Hash.Address
     )
 
-    belongs_to(:transaction, Transaction, foreign_key: :transaction_hash, references: :hash, type: Hash.Full)
+    belongs_to(:transaction, Transaction,
+      foreign_key: :transaction_hash,
+      primary_key: true,
+      references: :hash,
+      type: Hash.Full
+    )
 
     has_one(:token, through: [:token_contract_address, :token])
 
@@ -195,7 +201,7 @@ defmodule Explorer.Chain.TokenTransfer do
         tt in TokenTransfer,
         join: t in Token,
         on: tt.token_contract_address_hash == t.contract_address_hash,
-        select: {tt.token_contract_address_hash, count(tt.id)},
+        select: {tt.token_contract_address_hash, fragment("COUNT(*)")},
         group_by: tt.token_contract_address_hash
       )
 

apps/explorer/priv/repo/migrations/20181024172010_token_transfers_composite_primary_key.exs

@@ -0,0 +1,22 @@
+defmodule Explorer.Repo.Migrations.TokenTransfersCompositePrimaryKey do
+  use Ecto.Migration
+
+  def up do
+    # Remove old id
+    alter table(:token_transfers) do
+      remove(:id)
+    end
+
+    # Don't use `modify` as it requires restating the whole column description
+    execute("ALTER TABLE token_transfers ADD PRIMARY KEY (transaction_hash, log_index)")
+  end
+
+  def down do
+    execute("ALTER TABLE token_transfers DROP CONSTRAINT token_transfers_pkey")
+
+    # Add back old id
+    alter table(:token_transfers) do
+      add(:id, :bigserial, primary_key: true)
+    end
+  end
+end

apps/explorer/test/explorer/chain/token_transfer_test.exs

@@ -50,12 +50,15 @@ defmodule Explorer.Chain.TokenTransferTest do
         token: token
       )
 
-      transfers_ids =
+      transfers_primary_keys =
         token_contract_address.hash
         |> TokenTransfer.fetch_token_transfers_from_token_hash([])
-        |> Enum.map(& &1.id)
+        |> Enum.map(&{&1.transaction_hash, &1.log_index})
 
-      assert transfers_ids == [another_transfer.id, token_transfer.id]
+      assert transfers_primary_keys == [
+               {another_transfer.transaction_hash, another_transfer.log_index},
+               {token_transfer.transaction_hash, token_transfer.log_index}
+             ]
     end
 
     test "when there isn't token transfers won't show anything" do
@@ -101,14 +104,14 @@ defmodule Explorer.Chain.TokenTransferTest do
 
       paging_options = %PagingOptions{key: first_page.inserted_at, page_size: 1}
 
-      token_transfers_ids_paginated =
+      token_transfers_primary_keys_paginated =
         TokenTransfer.fetch_token_transfers_from_token_hash(
           token_contract_address.hash,
           paging_options: paging_options
         )
-        |> Enum.map(& &1.id)
+        |> Enum.map(&{&1.transaction_hash, &1.log_index})
 
-      assert token_transfers_ids_paginated == [second_page.id]
+      assert token_transfers_primary_keys_paginated == [{second_page.transaction_hash, second_page.log_index}]
     end
   end
 

apps/explorer/test/explorer/chain_test.exs

@@ -235,7 +235,10 @@ defmodule Explorer.ChainTest do
       insert(:token_transfer, to_address: build(:address), transaction: transaction)
 
       transaction = Chain.address_to_transactions(address) |> List.first()
-      assert transaction.token_transfers |> Enum.map(& &1.id) == [token_transfer.id]
+
+      assert transaction.token_transfers |> Enum.map(&{&1.transaction_hash, &1.log_index}) == [
+               {token_transfer.transaction_hash, token_transfer.log_index}
+             ]
     end
 
     test "returns just the token transfers related to the given contract address" do
@@ -250,7 +253,10 @@ defmodule Explorer.ChainTest do
       insert(:token_transfer, to_address: build(:address), transaction: transaction)
 
       transaction = Chain.address_to_transactions(contract_address) |> List.first()
-      assert Enum.map(transaction.token_transfers, & &1.id) == [token_transfer.id]
+
+      assert Enum.map(transaction.token_transfers, &{&1.transaction_hash, &1.log_index}) == [
+               {token_transfer.transaction_hash, token_transfer.log_index}
+             ]
     end
 
     test "returns all token transfers when the given address is the token contract address" do
@@ -572,12 +578,17 @@ defmodule Explorer.ChainTest do
         |> insert()
         |> with_block()
 
-      %TokenTransfer{id: token_transfer_id, token_contract_address_hash: token_contract_address_hash} =
-        insert(:token_transfer, to_address: address, transaction: transaction)
+      %TokenTransfer{
+        transaction_hash: token_transfer_transaction_hash,
+        log_index: token_transfer_log_index,
+        token_contract_address_hash: token_contract_address_hash
+      } = insert(:token_transfer, to_address: address, transaction: transaction)
 
       assert token_contract_address_hash
              |> Chain.fetch_token_transfers_from_token_hash()
-             |> Enum.map(& &1.id) == [token_transfer_id]
+             |> Enum.map(&{&1.transaction_hash, &1.log_index}) == [
+               {token_transfer_transaction_hash, token_transfer_log_index}
+             ]
     end
   end
 
@@ -778,7 +789,7 @@ defmodule Explorer.ChainTest do
         |> insert_list(:transaction)
         |> with_block()
 
-      %TokenTransfer{id: id1} =
+      %TokenTransfer{transaction_hash: transaction_hash1, log_index: log_index1} =
         insert(
           :token_transfer,
           to_address: address,
@@ -787,7 +798,7 @@ defmodule Explorer.ChainTest do
           token: token
         )
 
-      %TokenTransfer{id: id2} =
+      %TokenTransfer{transaction_hash: transaction_hash2, log_index: log_index2} =
         insert(
           :token_transfer,
           to_address: address,
@@ -799,7 +810,10 @@ defmodule Explorer.ChainTest do
       fetched_transactions = Explorer.Chain.hashes_to_transactions([transaction1.hash, transaction2.hash])
 
       assert Enum.all?(fetched_transactions, fn transaction ->
-               hd(transaction.token_transfers).id in [id1, id2]
+               %TokenTransfer{transaction_hash: transaction_hash, log_index: log_index} =
+                 hd(transaction.token_transfers)
+
+               {transaction_hash, log_index} in [{transaction_hash1, log_index1}, {transaction_hash2, log_index2}]
              end)
     end
   end
@@ -2004,9 +2018,11 @@ defmodule Explorer.ChainTest do
         |> insert()
         |> with_block()
 
-      %TokenTransfer{id: id} = insert(:token_transfer, transaction: transaction)
+      %TokenTransfer{transaction_hash: transaction_hash, log_index: log_index} =
+        insert(:token_transfer, transaction: transaction)
 
-      assert [%TokenTransfer{id: ^id}] = Chain.transaction_to_token_transfers(transaction)
+      assert [%TokenTransfer{transaction_hash: ^transaction_hash, log_index: ^log_index}] =
+               Chain.transaction_to_token_transfers(transaction)
     end
 
     test "token transfers necessity_by_association loads associations" do