ecto deadlock

ecto_deadlock3

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  1) test messages_count_after/2 returns messages count after the time (Exchat.ChannelRepoTest)
     test/models/channel_repo_test.exs:39
     ** (Postgrex.Error) ERROR (deadlock_detected): deadlock detected

     Process 46899 waits for ShareLock on transaction 8436; blocked by process 46892.
     Process 46892 waits for ShareLock on transaction 8431; blocked by process 46899.
     stacktrace:
       (ecto) lib/ecto/adapters/sql.ex:405: Ecto.Adapters.SQL.struct/6
       (ecto) lib/ecto/repo/schema.ex:373: Ecto.Repo.Schema.apply/5
       (ecto) lib/ecto/repo/schema.ex:179: anonymous fn/11 in Ecto.Repo.Schema.do_insert/4
       (ecto) lib/ecto/repo/schema.ex:581: anonymous fn/3 in Ecto.Repo.Schema.wrap_in_transaction/6
       (ecto) lib/ecto/adapters/sql.ex:450: anonymous fn/3 in Ecto.Adapters.SQL.do_transaction/3
       (db_connection) lib/db_connection.ex:1079: DBConnection.transaction_run/4
       (db_connection) lib/db_connection.ex:1009: DBConnection.run_begin/3
       (db_connection) lib/db_connection.ex:766: DBConnection.transaction/3
       (ecto) lib/ecto/repo/schema.ex:112: Ecto.Repo.Schema.insert!/4
       test/models/channel_repo_test.exs:41

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Finished in 1.8 seconds (0.5s on load, 1.3s on tests)
43 tests, 1 failure

Randomized with seed 692450