Why SELECT after UPDATE?

[frederikhors]

Using this code:

err := ent.WithTx(ctx, entClient, func(tx *generated.Tx) error {
  // other ops...
  
  entPlayer, err := tx.Player.UpdateOneID(id).SetName(newName).Save(ctx)
  // handle err

  // use entPlayer here...

  return nil
})
// handle err

I expect to have only the UPDATE SQL query.

Instead I get UPDATE and SELECT:

2022/06/04 16:14:34 driver.Tx(9d59627b-7d40-4cc6-b8cb-5e8b9c3748e4): started

2022/06/04 16:14:34 Tx(9d59627b-7d40-4cc6-b8cb-5e8b9c3748e4).Exec: query=UPDATE "players" SET "updated_at" = $1, "name" = $2 WHERE "id" = $3 AND "players"."tenant_id" = $4 args=[2022-06-04 16:14:34.3706568 John 1 2]

2022/06/04 16:14:34 Tx(9d59627b-7d40-4cc6-b8cb-5e8b9c3748e4).Query: query=SELECT "id", "created_at", "updated_at", "tenant_id", "name" FROM "players" WHERE "id" = $1 AND "players"."tenant_id" = $2 args=[1 2]

2022/06/04 16:14:34 Tx(9d59627b-7d40-4cc6-b8cb-5e8b9c3748e4): committed

Why?

I tried with .Exec() too but it's the same.

[a8m]

The Exec option uses Save under the hood and load the record - the same layer used by hooks/privacy of UpdateOne operation. If you don't want to load the record, use Update().Where(player.ID(id))....Exec(ctx) instead.

[frederikhors]

Oh. Ok. Is not possible today. Ok. So in future the SELECT after the UPDATE will vanish, right?

[a8m]

Yes. The sqlgraph (some of Ent runtime code) was written before SQLite supported it, and this was a PostgreSQL thing. The change is not that big (a few if statements). I'll try to give it a look soon, but as mentioned, we already have commitments for v0.11 and we really want to close this release (95% done).

[frederikhors]

@a8m No problem. You are doing a Guinness job! 😄

I ask you some questions just to UNDERSTAND. And mostly to give justification to the team (I'm the one pushing to use Ent).

I'll open an issue for this so we can track it, if you don't mind.

[rubensayshi]

@a8m is there any limitation why Exec needs to call Save under the hood?
or should it be doable for me to make a PR that for Exec doesn't assign the ScanValues and as a result won't trigger a SELECT ?

[a8m]

Hey @rubensayshi! It's great to see you here again 😃
The last time I experimented with it, I found that some mutation/policy code of ours (and other users) was relying on it. Here's one of them: #2112.

I still think the issue mentioned here should be addressed and added to the upcoming release.