explain.depesz.com

PostgreSQL's explain analyze made readable

Result: 5S4e

Settings
# exclusive inclusive rows x rows loops node
1. 0.002 0.077 ↓ 0.0 0 1

Nested Loop (cost=4.33..17.38 rows=853,600 width=1,430) (actual time=0.076..0.077 rows=0 loops=1)

  • Output: s.id, s.account_id, s.can_submit_feedback, s.change_chapter_state, s.checkpoint_failed_responses_count, s.course_id, s.custom_goal, s.goal_execution_plan, s.is_pretest_done, s.knewton_registration_id, s.module_execution_plan, s.
  • Join Filter: (s.id = w.student_registration_id)
2. 0.010 0.045 ↑ 1.0 1 1

Nested Loop (cost=0.00..2.05 rows=1 width=1,045) (actual time=0.043..0.045 rows=1 loops=1)

  • Output: s.id, s.account_id, s.can_submit_feedback, s.change_chapter_state, s.checkpoint_failed_responses_count, s.course_id, s.custom_goal, s.goal_execution_plan, s.is_pretest_done, s.knewton_registration_id, s.module_execution_pl
  • Inner Unique: true
  • Join Filter: (s.account_id = a.id)
3. 0.025 0.025 ↑ 1.0 1 1

Seq Scan on public.student_registrations s (cost=0.00..1.01 rows=1 width=1,037) (actual time=0.024..0.025 rows=1 loops=1)

  • Output: s.id, s.knewton_registration_id, s.course_id, s.account_id, s.pending_textbook_path, s.change_chapter_state, s.is_pretest_done, s.module_execution_plan, s.recent_module_ids, s.previously_recommended_module_ids, s.can
  • Filter: (s.course_id = 1)
4. 0.010 0.010 ↑ 1.0 1 1

Seq Scan on public.accounts a (cost=0.00..1.02 rows=1 width=8) (actual time=0.010..0.010 rows=1 loops=1)

  • Output: a.id
  • Filter: (a.user_id = 'Tibet-284244'::text)
  • Rows Removed by Filter: 1
5. 0.001 0.030 ↓ 0.0 0 1

Nested Loop (cost=4.33..15.09 rows=19 width=385) (actual time=0.029..0.030 rows=0 loops=1)

  • Output: w.id, w.continuous_worktime_by_chapter, w.milliseconds_since_last_interaction, w.student_registration_id, w.updated, w.worktime_in_milliseconds_by_iso_date, s0.id, s0.correct_results, s0.correct_streak, s0.given_up_count,
  • Join Filter: (w.student_registration_id = a0.student_registration_id)
6. 0.007 0.029 ↓ 0.0 0 1

Nested Loop (cost=4.18..13.69 rows=4 width=329) (actual time=0.029..0.029 rows=0 loops=1)

  • Output: w.id, w.continuous_worktime_by_chapter, w.milliseconds_since_last_interaction, w.student_registration_id, w.updated, w.worktime_in_milliseconds_by_iso_date, s0.id, s0.correct_results, s0.correct_streak, s0.given_up_c
7. 0.006 0.006 ↑ 1.0 1 1

Seq Scan on public.worktime w (cost=0.00..1.01 rows=1 width=265) (actual time=0.004..0.006 rows=1 loops=1)

  • Output: w.id, w.worktime_in_milliseconds_by_iso_date, w.updated, w.continuous_worktime_by_chapter, w.milliseconds_since_last_interaction, w.student_registration_id
8. 0.006 0.016 ↓ 0.0 0 1

Bitmap Heap Scan on public.scores s0 (cost=4.18..12.64 rows=4 width=64) (actual time=0.016..0.016 rows=0 loops=1)

  • Output: s0.id, s0.textbook_path, s0.correct_streak, s0.correct_results, s0.wrong_results, s0.given_up_count, s0.student_registration_id
  • Recheck Cond: (s0.student_registration_id = w.student_registration_id)
9. 0.010 0.010 ↓ 0.0 0 1

Bitmap Index Scan on ix_scores_student_registration_id (cost=0.00..4.18 rows=4 width=0) (actual time=0.010..0.010 rows=0 loops=1)

  • Index Cond: (s0.student_registration_id = w.student_registration_id)
10. 0.000 0.000 ↓ 0.0 0

Index Scan using ix_achievements_student_registration_id on public.achievements a0 (cost=0.15..0.29 rows=5 width=56) (never executed)

  • Output: a0.id, a0.textbook_path, a0.streak_achievements, a0.work_time_achievements, a0.student_registration_id
  • Index Cond: (a0.student_registration_id = s0.student_registration_id)
Planning time : 2.588 ms
Execution time : 0.261 ms