Class: Users::AssignedIssuesCountService

Inherits:
BaseCountService show all
Defined in:
app/services/users/assigned_issues_count_service.rb

Instance Method Summary collapse

Methods inherited from BaseCountService

#count, #count_stored?, #delete_cache, #raw?, #refresh_cache, #relation_for_count, #update_cache_for_key

Constructor Details

#initialize(current_user:, max_limit: User::MAX_LIMIT_FOR_ASSIGNEED_ISSUES_COUNT) ⇒ AssignedIssuesCountService

Returns a new instance of AssignedIssuesCountService.



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# File 'app/services/users/assigned_issues_count_service.rb', line 5

def initialize(current_user:, max_limit: User::MAX_LIMIT_FOR_ASSIGNEED_ISSUES_COUNT)
  @current_user = current_user
  @max_limit = max_limit
end

Instance Method Details

#cache_key ⇒ Object 



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# File 'app/services/users/assigned_issues_count_service.rb', line 10

def cache_key
  ['users', @current_user.id, 'max_assigned_open_issues_count']
end

#cache_options ⇒ Object 



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# File 'app/services/users/assigned_issues_count_service.rb', line 14

def cache_options
  { force: false, expires_in: User::COUNT_CACHE_VALIDITY_PERIOD }
end

#uncached_count ⇒ Object

rubocop: disable CodeReuse/ActiveRecord



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# File 'app/services/users/assigned_issues_count_service.rb', line 19

def uncached_count
  # When a user has many assigned issues, counting them all can be very slow.
  # As a workaround, we will short-circuit the counting query once the count reaches some threshold.
  #
  # Concretely, given a threshold, say 100 (= max_limit),
  # iterate through the first 100 issues, sorted by ID desc, assigned to the user using `issue_assignees` table.
  # For each issue iterated, use IssuesFinder to check if the issue should be counted.
  initializer = IssueAssignee
    .select(:issue_id).joins(", LATERAL (#{finder_constraint.to_sql}) as issues")
    .where(user_id: @current_user.id)
    .order(issue_id: :desc)
    .limit(1)
  recursive_finder = initializer.where("issue_assignees.issue_id < assigned_issues.issue_id")

  cte = <<~SQL
    WITH RECURSIVE assigned_issues AS (
      (
        #{initializer.to_sql}
      )
      UNION ALL
      (
        SELECT next_assigned_issue.issue_id
        FROM assigned_issues,
          LATERAL (
            #{recursive_finder.to_sql}
          ) next_assigned_issue
      )
    ) SELECT COUNT(*) FROM (SELECT * FROM assigned_issues LIMIT #{@max_limit}) issues
  SQL

  ApplicationRecord.connection.execute(cte).first["count"]
end