Class: WorkerPlugins::RemoveQuery

Inherits:
ApplicationService show all
Defined in:
app/services/worker_plugins/remove_query.rb

Instance Method Summary collapse

Methods inherited from ApplicationService

#db_now_value, #mysql?, #postgres?, #quote, #quote_column, #quote_table, #sqlite?

Instance Method Details



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# File 'app/services/worker_plugins/remove_query.rb', line 8

def links_scope
  scope = workplace.workplace_links.where(resource_type: model_class.name)
  return scope if unscoped_query?

  scope.where(resource_id: query_with_selected_ids)
end

#model_class ⇒ Object 



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# File 'app/services/worker_plugins/remove_query.rb', line 37

def model_class
  query.klass
end

#perform ⇒ Object 



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# File 'app/services/worker_plugins/remove_query.rb', line 4

def perform
  succeed!(affected_count: links_scope.delete_all)
end

#query_with_selected_ids ⇒ Object 



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# File 'app/services/worker_plugins/remove_query.rb', line 41

def query_with_selected_ids
  WorkerPlugins::SelectColumnWithTypeCast.execute!(
    column_name_to_select: :id,
    column_to_compare_with: WorkerPlugins::WorkplaceLink.column_for_attribute(:resource_id),
    query: query.except(:order)
  )
end

#unscoped_query? ⇒ Boolean

If the caller’s query has no meaningful scoping applied, the ‘resource_id IN (SELECT … FROM <target_table>)` subquery would simply materialize every row of the target model — for 340k+ users that’s a full-table scan with no semantic effect other than preserving orphaned links. The ‘resource_type = ?` filter alone is enough to pin the DELETE to this workplace’s links of the given type, so we short-circuit the subquery in that case. Orphaned links (whose resource row has since been deleted) are deleted alongside live ones, which matches caller intent (“remove everything matching the query”) and is the correct thing to do with dead references anyway.

Returns:

  • (Boolean) 


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# File 'app/services/worker_plugins/remove_query.rb', line 25

def unscoped_query?
  @query.where_clause.empty? &&
    @query.joins_values.empty? &&
    @query.left_outer_joins_values.empty? &&
    @query.group_values.empty? &&
    @query.having_clause.empty? &&
    @query.limit_value.nil? &&
    @query.offset_value.nil? &&
    @query.from_clause.value.nil? &&
    @query.with_values.empty?
end