Problem: due to the unsatisfying performance of the main page some ETS-based cache has been deemed necessary. In this particular case one for the most recent collated transactions. Solution: implementation of said transactions cachepull/2283/head
pasqu4le
5 years ago
parent
4bbfe20d7c
commit
bef66e846f
@ -0,0 +1,143 @@ |
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defmodule Explorer.Chain.TransactionsCache do |
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@moduledoc """ |
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Caches the latest imported transactions |
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""" |
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|
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alias Explorer.Chain.Transaction |
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alias Explorer.Repo |
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|
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@transactions_ids_key "transactions_ids" |
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@cache_name :transactions |
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@max_size 51 |
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@preloads [ |
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:block, |
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created_contract_address: :names, |
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from_address: :names, |
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to_address: :names, |
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token_transfers: :token, |
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token_transfers: :from_address, |
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token_transfers: :to_address |
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] |
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|
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@spec cache_name :: atom() |
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def cache_name, do: @cache_name |
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|
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@doc """ |
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Fetches a transaction from its id ({block_number, index}), returns nil if not found |
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""" |
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@spec get({non_neg_integer(), non_neg_integer()}) :: Transaction.t() | nil |
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def get(id), do: ConCache.get(@cache_name, id) |
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|
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@doc """ |
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Return the current number of transactions stored |
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""" |
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@spec size :: non_neg_integer() |
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def size, do: Enum.count(transactions_ids()) |
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|
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@doc """ |
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Checks if there are enough transactions stored |
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""" |
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@spec enough?(non_neg_integer()) :: boolean() |
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def enough?(amount) do |
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amount <= size() |
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end |
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|
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@doc """ |
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Checks if the number of transactions stored is already the max allowed |
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""" |
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@spec full? :: boolean() |
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def full? do |
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@max_size <= size() |
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end |
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|
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@doc "Returns the list ids of the transactions currently stored" |
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@spec transactions_ids :: [{non_neg_integer(), non_neg_integer()}] |
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def transactions_ids do |
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ConCache.get(@cache_name, @transactions_ids_key) || [] |
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end |
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@doc "Returns all the stored transactions" |
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@spec all :: [Transaction.t()] |
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def all, do: Enum.map(transactions_ids(), &get(&1)) |
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|
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@doc "Returns the `n` most recent transactions stored" |
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@spec take(integer()) :: [Transaction.t()] |
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def take(amount) do |
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transactions_ids() |
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|> Enum.take(amount) |
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|> Enum.map(&get(&1)) |
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end |
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@doc """ |
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Returns the `n` most recent transactions, unless there are not as many stored, |
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in which case returns `nil` |
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""" |
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@spec take_enough(integer()) :: [Transaction.t()] | nil |
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def take_enough(amount) do |
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if enough?(amount), do: take(amount) |
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end |
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@doc """ |
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Adds a transaction (or a list of transactions). |
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If the cache is already full, the transaction will be only stored if it can take |
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the place of a less recent one. |
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NOTE: each transaction is inserted atomically |
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""" |
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@spec update([Transaction.t()] | Transaction.t() | nil) :: :ok |
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def update(transactions) when is_nil(transactions), do: :ok |
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def update(transactions) when is_list(transactions) do |
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Enum.map(transactions, &update(&1)) |
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end |
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def update(transaction) do |
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ConCache.isolated(@cache_name, @transactions_ids_key, fn -> |
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transaction_id = {transaction.block_number, transaction.index} |
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ids = transactions_ids() |
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if full?() do |
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{init, [min]} = Enum.split(ids, -1) |
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cond do |
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transaction_id < min -> |
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:ok |
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transaction_id > min -> |
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insert_transaction(transaction_id, transaction, init) |
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ConCache.delete(@cache_name, min) |
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transaction_id == min -> |
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put_transaction(transaction_id, transaction) |
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end |
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else |
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insert_transaction(transaction_id, transaction, ids) |
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end |
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end) |
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end |
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defp insert_transaction(transaction_id, transaction, ids) do |
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put_transaction(transaction_id, transaction) |
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ConCache.put(@cache_name, @transactions_ids_key, insert_sorted(transaction_id, ids)) |
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end |
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defp put_transaction(transaction_id, transaction) do |
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full_transaction = Repo.preload(transaction, @preloads) |
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ConCache.put(@cache_name, transaction_id, full_transaction) |
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end |
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defp insert_sorted(id, ids) do |
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case ids do |
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[] -> |
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[id] |
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[head | tail] -> |
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cond do |
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head > id -> [head | insert_sorted(id, tail)] |
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head < id -> [id | ids] |
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head == id -> ids |
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end |
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end |
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end |
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end |
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@ -0,0 +1,95 @@ |
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defmodule Explorer.Chain.TransactionsCacheTest do |
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use Explorer.DataCase |
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alias Explorer.Chain.TransactionsCache |
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alias Explorer.Repo |
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@size 51 |
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describe "update/1" do |
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test "adds a new value to a new cache with preloads" do |
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transaction = insert(:transaction) |> preload_all() |
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TransactionsCache.update(transaction) |
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assert TransactionsCache.take(1) == [transaction] |
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end |
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test "adds several elements, removing the oldest when necessary" do |
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transactions = |
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1..@size |
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|> Enum.map(fn n -> |
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block = insert(:block, number: n) |
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insert(:transaction) |> with_block(block) |
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end) |
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TransactionsCache.update(transactions) |
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assert TransactionsCache.all() == Enum.reverse(preload_all(transactions)) |
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more_transactions = |
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(@size + 1)..(@size + 10) |
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|> Enum.map(fn n -> |
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block = insert(:block, number: n) |
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insert(:transaction) |> with_block(block) |
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end) |
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TransactionsCache.update(more_transactions) |
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kept_transactions = |
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Enum.reverse(transactions ++ more_transactions) |
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|> Enum.take(@size) |
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|> preload_all() |
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assert TransactionsCache.take(@size) == kept_transactions |
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end |
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test "does not add a transaction too old when full" do |
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transactions = |
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10..(@size + 9) |
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|> Enum.map(fn n -> |
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block = insert(:block, number: n) |
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insert(:transaction) |> with_block(block) |
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end) |
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TransactionsCache.update(transactions) |
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loaded_transactions = Enum.reverse(preload_all(transactions)) |
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assert TransactionsCache.all() == loaded_transactions |
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block = insert(:block, number: 1) |
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insert(:transaction) |> with_block(block) |> TransactionsCache.update() |
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assert TransactionsCache.all() == loaded_transactions |
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end |
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test "adds intermediate transactions" do |
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blocks = 1..10 |> Map.new(fn n -> {n, insert(:block, number: n)} end) |
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insert(:transaction) |> with_block(blocks[1]) |> TransactionsCache.update() |
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insert(:transaction) |> with_block(blocks[10]) |> TransactionsCache.update() |
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assert TransactionsCache.size() == 2 |
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insert(:transaction) |> with_block(blocks[5]) |> TransactionsCache.update() |
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assert TransactionsCache.size() == 3 |
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end |
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end |
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defp preload_all(transactions) when is_list(transactions) do |
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Enum.map(transactions, &preload_all(&1)) |
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end |
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defp preload_all(transaction) do |
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Repo.preload(transaction, [ |
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:block, |
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created_contract_address: :names, |
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from_address: :names, |
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to_address: :names, |
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token_transfers: :token, |
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token_transfers: :from_address, |
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token_transfers: :to_address |
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]) |
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end |
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end |
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