Problem with Nested relations saving the same document

[pavelivanov]

Hi there! I need ur help. I'm trying to create game statistic, and I wrote simple models (Games, Teams, Rounds, Score) and these relations:

Game.hasAndBelongsToMany(Team, 'teams', 'id', 'id')
Game.hasMany(Round, 'rounds', 'id', 'game_id')
Round.hasMany(Score, 'score', 'id', 'round_id')
Team.hasMany(Score, 'score', 'id', 'team_id')

And in api I do this:

  const game      = new Game({ ... })
  const teams     = req.body.teams.map(() => new Team({ ... }))
  const reounds   = req.body.rounds.map(() => {
                      const round = new Round({ ... })
                      round.score = round.score.map(() => {
                        const score = new Score({ ... })
                        teams[index].score.push(score)
                        return score
                      })
                      return round
                    })

  game.teams = teams
  game.reounds = reounds

  game.saveAll({ teams: { score: true }, rounds: { score: true } })

Everything saving, but there is a problem in Score records (team_id missed sometimes):

[
  {
    "id": "3d9131cc-8f6f-4ba2-a147-2b9e216ea5c1",
    "round_id": "b9c1471a-70e1-492a-9f9d-d9fba4afe7c4",
    "score": 6
  },
  {
    "id": "4949756f-9a85-4d6a-8d5a-150c7c31639a",
    "round_id": "1eda126b-ee72-4598-a946-af2b63298f59",
    "score": 1,
    "team_id": "81aa1618-4f77-424c-a9bf-e62c4077a4a2"
  },
  {
    "id": "d0ab2cc1-7c1f-459c-bd0f-1f32072fd616",
    "round_id": "b9c1471a-70e1-492a-9f9d-d9fba4afe7c4",
    "score": 12
  },
  {
    "id": "06737e74-b374-4791-abdd-28843c7519d8",
    "round_id": "494d141d-ac1f-405e-bc1e-aa3154f55cde",
    "score": 4
  },
  {
    "id": "37841d0a-d07d-4b71-a2af-184b8e5918db",
    "round_id": "84298436-a9aa-427f-baf5-1ad3a24358f0",
    "score": 1,
    "team_id": "f8f5dce5-7d75-4cd3-a937-02817f259e3c"
  }
]

[neumino]

Can you provide a full script that I can run that reproduce this error?

[pavelivanov]

Is it ok? Or u'd prefer full working example ?)

const Game = thinky.createModel('Game', {
  id: String,
  name: String,
  created: {
    _type: Date,
    default: r.now()
  },
})

Game.ensureIndex('created')

const Team = thinky.createModel('Team', {
  id: String,
  name: String,
})

Team.ensureIndex('name')

const Round = thinky.createModel('Round', {
  id: String,
  index: Number,
})

Round.ensureIndex('index')

const Score = thinky.createModel('Score', {
  id: String,
  score: Number,
})

Score.ensureIndex('score')

export const add = (req, res) => {
  const game = new Game({ name: 'Game 1' })

  const team_1  = new Team({ name: 'Team 1' })
  const team_2  = new Team({ name: 'Team 2' })
  const teams   = [ team_1, team_2 ]

  const round_1 = new Round({ index: 0 })
  const round_2 = new Round({ index: 1 })
  const rounds  = [ round_1, round_2 ]

  const round_1_score_1 = new Score({ score: 5 })
  const round_1_score_2 = new Score({ score: 2 })
  const round_2_score_1 = new Score({ score: 1 })
  const round_2_score_2 = new Score({ score: 3 })

  team_1.score = [ round_1_score_1, round_2_score_1 ]
  team_2.score = [ round_1_score_2, round_2_score_2 ]

  round_1.score = [ round_1_score_1, round_1_score_2 ]
  round_2.score = [ round_2_score_1, round_2_score_2 ]

  game.teams = teams
  game.rounds = rounds

  game
    .saveAll({ teams: { score: true }, rounds: { score: true } })
    .then(() => {
      res.json({ success: true })
    })
    .error((error) => {
      res.json({ message: error })
    })
}

[pavelivanov]

@neumino hi! sry for disturbing) do u have any ideas?

[neumino]

Can you provide the relations between your model?

[neumino]

Never mind, they are in the first message.

[neumino]

Ok I see what's happening. It's a bit tricky, but when you do game.saveAll, this is what happens:

• thinky finds teams and scores documents that it has to save and will save them in parallel.
• For each of these team/score, it finds a score to save, it happens that here the score are the same, so thinky save them twice (once via team and once via score).
• The order in which the scores are saved is not deterministic. So one save operation may overwrite the other one.

This is a work around for now:

var thinky = require('./lib/thinky.js')();
var r = thinky.r;

const Game = thinky.createModel('Game', {
  id: String,
  name: String,
  created: {
    _type: Date,
    default: r.now()
  },
})

Game.ensureIndex('created')

const Team = thinky.createModel('Team', {
  id: String,
  name: String,
})

Team.ensureIndex('name')

const Round = thinky.createModel('Round', {
  id: String,
  index: Number,
})

Round.ensureIndex('index')

const Score = thinky.createModel('Score', {
  id: String,
  score: Number,
})

Score.ensureIndex('score')

Game.hasAndBelongsToMany(Team, 'teams', 'id', 'id')
Game.hasMany(Round, 'rounds', 'id', 'game_id')
Round.hasMany(Score, 'score', 'id', 'round_id')
Team.hasMany(Score, 'score', 'id', 'team_id')

const game = new Game({ name: 'Game 1' })

const team_1  = new Team({ name: 'Team 1' })
const team_2  = new Team({ name: 'Team 2' })
const teams   = [ team_1, team_2 ]

const round_1 = new Round({ index: 0 })
const round_2 = new Round({ index: 1 })
const rounds  = [ round_1, round_2 ]

const round_1_score_1 = new Score({ score: 5 })
const round_1_score_2 = new Score({ score: 2 })
const round_2_score_1 = new Score({ score: 1 })
const round_2_score_2 = new Score({ score: 3 })

team_1.score = [ round_1_score_1, round_2_score_1 ]
team_2.score = [ round_1_score_2, round_2_score_2 ]

round_1.score = [ round_1_score_1, round_1_score_2 ]
round_2.score = [ round_2_score_1, round_2_score_2 ]

game.teams = teams
game.rounds = rounds

game
    .saveAll({
      teams: {
        score: true
      }
    }).then(() => {
      console.log('-- save success');
      return game.saveAll({
      rounds: {
        score: true
      },
    })
    }).then(() => {
      return Game.get(game.id).getJoin({
      teams: {
        score: true
      },
      rounds: {
        score: true
      }
      }).run()
    }).then(() => {
      console.log('-- retrieve success');
      console.log(JSON.stringify(game, null, 2));
    }).error((error) => {
      console.log('error', JSON.stringify(error, null, 2));
    })

As for the real fix, there are a few ways to fix that:

• Don't save things in parallel -- but that's slowish
• Make documents being saved in a given operation and make another save operation wait for the previous one -- that's as fast as today but we still have multiple writes for the same document
• Find all the documents to save, find duplicate save, merge them and save everything -- that's the best solution, but requires more work

[pavelivanov]

@neumino I see! thank you for explanation!