seeing n+1 queries even if using with_read_marks_for

[aa365]

Running the following code, I'm seeing a lot of n+1 queries. They're hitting the ActiveRecord cache so there is no performance hit, but I was wondering if this is expected behaviour:

Event.all.with_read_marks_for(user).each { |e| puts e.unread?(user) }

Here's the log output:

User Load (0.2ms)  SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2  [["id", 38], ["LIMIT", 1]]
Event Load (0.6ms)  SELECT "events".*,
                                        "read_marks".id AS read_mark_id,
                                        'User'::varchar AS read_mark_reader_type,
                                        38 AS read_mark_reader_id FROM "events" LEFT JOIN "read_marks"
                ON "read_marks".readable_type  = 'Event'
               AND "read_marks".readable_id    = "events"."id"
               AND "read_marks".reader_id      = 38
               AND "read_marks".reader_type    = 'User'
               AND "read_marks".timestamp     >= "events"."updated_at"

ReadMark Load (0.3ms)  SELECT "read_marks".* FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 AND "read_marks"."readable_id" IS NULL ORDER BY "read_marks"."id" ASC LIMIT $4  [["reader_id", 38], ["reader_type", "User"], ["readable_type", "Event"], ["LIMIT", 1]]

  CACHE ReadMark Load (0.0ms)  SELECT "read_marks".* FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 AND "read_marks"."readable_id" IS NULL ORDER BY "read_marks"."id" ASC LIMIT $4  [["reader_id", 38], ["reader_type", "User"], ["readable_type", "Event"], ["LIMIT", 1]]

  CACHE ReadMark Load (0.0ms)  SELECT "read_marks".* FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 AND "read_marks"."readable_id" IS NULL ORDER BY "read_marks"."id" ASC LIMIT $4  [["reader_id", 38], ["reader_type", "User"], ["readable_type", "Event"], ["LIMIT", 1]]

  CACHE ReadMark Load (0.0ms)  SELECT "read_marks".* FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 AND "read_marks"."readable_id" IS NULL ORDER BY "read_marks"."id" ASC LIMIT $4  [["reader_id", 38], ["reader_type", "User"], ["readable_type", "Event"], ["LIMIT", 1]]

  CACHE ReadMark Load (0.0ms)  SELECT "read_marks".* FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 AND "read_marks"."readable_id" IS NULL ORDER BY "read_marks"."id" ASC LIMIT $4  [["reader_id", 38], ["reader_type", "User"], ["readable_type", "Event"], ["LIMIT", 1]]

[ledermann]

Thanks for reporting.

Just fixed a memoization issue. Please check your code against the unreleased gem by adding this to your Gemfile:

gem 'unread', github: 'ledermann/unread'

If it works for you, I will publish a new release.

[aa365]

that's fixed it. Thanks for the quick response! 👍