هناك بعض المواضيع الأخرى المتعلقة بضبط الأداء للinstances الكبيرة. مبادئ تشغيل PostgreSQL كبير هي نفسها MySQL، لكن الشيطان يكمن في التفاصيل.
نحن نحاول بالفعل البحث في الموضوع عبر الإنترنت وعلى منصة Meta. هل هناك أي مواضيع يمكنك إرسالها إلينا وتعتقد أنها قد تكون مفيدة؟
يحتوي ملف app.yml الحالي لديك على هذه الأسطر معلقًا:
قم بإلغاء التعليق عن هذه الأسطر وزيّن القيم وفقًا لذلك. بعد ذلك، يجب عليك إعادة البناء.
3 إعجابات
لقد قمت بذلك وأعدت بناء الحاوية. أحاول إعادة تشغيل عملية إعادة الفهرسة مرة أخرى، ولكن يبدو أنها عالقة مرة أخرى. إليك ما لدي بخصوص هذين الأمرين:
هل توجد طريقة لمعرفة ما إذا كان من الممكن أن نحتاج إلى رفع قيمة work_mem؟ أرى أن القرص يتعرض لضغط كبير، لذا أعتقد أنه قد يكون يقوم بفرز على مستوى نظام الملفات أو ما شابه، لكنني لست متأكدًا من كيفية التأكد من صحة ذلك أو ما إذا كان هناك شيء آخر يحدث.
إعجاب واحد (1)
استخدم الاستعلامات التي ذكرتها في المنشور الأصلي. قم بتشغيلها في واجهة psql مع إضافة EXPLAIN ANALYZE في البداية، ثم انسخ المخرجات وألصقها هنا.
إعجابَين (2)
Looks like there’s some caching at work so subsequent loads tend to be faster, but > 5 seconds is still brutal when the cache expires.
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=26396.41..26397.10 rows=6 width=1278) (actual time=90.879..114.499 rows=6 loops=1)
-> Gather Merge (cost=26396.41..26448.85 rows=456 width=1278) (actual time=90.877..114.496 rows=6 loops=1)
Workers Planned: 1
Workers Launched: 1
-> Sort (cost=25396.40..25397.54 rows=456 width=1278) (actual time=87.195..87.197 rows=5 loops=2)
Sort Key: posts.like_count DESC, posts.created_at DESC
Sort Method: top-N heapsort Memory: 38kB
Worker 0: Sort Method: top-N heapsort Memory: 39kB
-> Nested Loop (cost=103.30..25388.23 rows=456 width=1278) (actual time=3.200..83.497 rows=3610 loops=2)
-> Parallel Bitmap Heap Scan on posts (cost=99.06..9509.95 rows=1356 width=783) (actual time=3.075..56.880 rows=5932 loops=2)
Recheck Cond: (user_id = 27510)
Filter: ((deleted_at IS NULL) AND (post_number > 1) AND (post_type = ANY ('{1,2,3,4}'::integer[])))
Rows Removed by Filter: 1071
Heap Blocks: exact=6272
-> Bitmap Index Scan on index_posts_on_user_id_and_created_at (cost=0.00..98.48 rows=2389 width=0) (actual time=3.916..3.917 rows=20157 loops=1)
Index Cond: (user_id = 27510)
-> Index Scan using topics_pkey on topics (cost=4.24..11.71 rows=1 width=495) (actual time=0.004..0.004 rows=1 loops=11864)
Index Cond: (id = posts.topic_id)
Filter: ((deleted_at IS NULL) AND (deleted_at IS NULL) AND visible AND ((archetype)::text <> 'private_message'::text) AND ((category_id IS NULL) OR (hashed SubPlan 1)))
Rows Removed by Filter: 0
SubPlan 1
-> Seq Scan on categories (cost=0.00..3.74 rows=28 width=4) (actual time=0.013..0.029 rows=35 loops=2)
Filter: ((NOT read_restricted) OR (id = ANY ('{3,4,5,17,19,25,26,27,28}'::integer[])))
Planning Time: 2.535 ms
Execution Time: 114.657 ms
(25 rows)
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=25004.87..25004.87 rows=1 width=1464) (actual time=98.136..121.987 rows=6 loops=1)
-> Sort (cost=25004.87..25004.87 rows=1 width=1464) (actual time=98.134..121.984 rows=6 loops=1)
Sort Key: topic_links.clicks DESC, topic_links.created_at DESC
Sort Method: top-N heapsort Memory: 55kB
-> Nested Loop (cost=1103.75..25004.86 rows=1 width=1464) (actual time=6.763..118.114 rows=3443 loops=1)
-> Gather (cost=1099.51..24993.34 rows=1 width=969) (actual time=6.464..88.294 rows=9130 loops=1)
Workers Planned: 1
Workers Launched: 1
-> Nested Loop (cost=99.51..23993.24 rows=1 width=969) (actual time=3.151..73.939 rows=4565 loops=2)
-> Parallel Bitmap Heap Scan on posts (cost=99.08..9506.46 rows=1405 width=783) (actual time=3.032..43.325 rows=7003 loops=2)
Recheck Cond: (user_id = 27510)
Filter: ((deleted_at IS NULL) AND (post_type = ANY ('{1,2,3,4}'::integer[])))
Heap Blocks: exact=5953
-> Bitmap Index Scan on index_posts_on_user_id_and_created_at (cost=0.00..98.48 rows=2389 width=0) (actual time=3.790..3.791 rows=20157 loops=1)
Index Cond: (user_id = 27510)
-> Index Scan using index_topic_links_on_post_id on topic_links (cost=0.43..10.30 rows=1 width=186) (actual time=0.003..0.004 rows=1 loops=14006)
Index Cond: (post_id = posts.id)
Filter: ((NOT internal) AND (NOT reflection) AND (NOT quote) AND (user_id = 27510))
Rows Removed by Filter: 0
-> Index Scan using topics_pkey on topics (cost=4.24..11.52 rows=1 width=495) (actual time=0.003..0.003 rows=0 loops=9130)
Index Cond: (id = topic_links.topic_id)
Filter: ((deleted_at IS NULL) AND (deleted_at IS NULL) AND visible AND ((archetype)::text <> 'private_message'::text) AND ((category_id IS NULL) OR (hashed SubPlan 1)))
Rows Removed by Filter: 1
SubPlan 1
-> Seq Scan on categories (cost=0.00..3.74 rows=28 width=4) (actual time=0.009..0.022 rows=35 loops=1)
Filter: ((NOT read_restricted) OR (id = ANY ('{3,4,5,17,19,25,26,27,28}'::integer[])))
Planning Time: 1.102 ms
Execution Time: 122.098 ms
(28 rows)
SELECT "posts"."id" AS t0_r0, "posts"."user_id" AS t0_r1, "posts"."topic_id" AS t0_r2, "posts"."post_number" AS t0_r3, "posts"."raw" AS t0_r4, "posts"."cooked" AS t0_r5, "posts"."created_at" AS t0_r6, "posts"."updated_at" AS t0_r7, "posts"."reply_to_post_number" AS t0_r8, "posts"."reply_count" AS t0_r9, "posts"."quote_count" AS t0_r10, "posts"."deleted_at" AS t0_r11, "posts"."off_topic_count" AS t0_r12, "posts"."like_count" AS t0_r13, "posts"."incoming_link_count" AS t0_r14, "posts"."bookmark_count" AS t0_r15, "posts"."score" AS t0_r16, "posts"."reads" AS t0_r17, "posts"."post_type" AS t0_r18, "posts"."sort_order" AS t0_r19, "posts"."last_editor_id" AS t0_r20, "posts"."hidden" AS t0_r21, "posts"."hidden_reason_id" AS t0_r22, "posts"."notify_moderators_count" AS t0_r23, "posts"."spam_count" AS t0_r24, "posts"."illegal_count" AS t0_r25, "posts"."inappropriate_count" AS t0_r26, "posts"."last_version_at" AS t0_r27, "posts"."user_deleted" AS t0_r28, "posts"."reply_to_user_id" AS t0_r29, "posts"."percent_rank" AS t0_r30, "posts"."notify_user_count" AS t0_r31, "posts"."like_score" AS t0_r32, "posts"."deleted_by_id" AS t0_r33, "posts"."edit_reason" AS t0_r34, "posts"."word_count" AS t0_r35, "posts"."version" AS t0_r36, "posts"."cook_method" AS t0_r37, "posts"."wiki" AS t0_r38, "posts"."baked_at" AS t0_r39, "posts"."baked_version" AS t0_r40, "posts"."hidden_at" AS t0_r41, "posts"."self_edits" AS t0_r42, "posts"."reply_quoted" AS t0_r43, "posts"."via_email" AS t0_r44, "posts"."raw_email" AS t0_r45, "posts"."public_version" AS t0_r46, "posts"."action_code" AS t0_r47, "posts"."locked_by_id" AS t0_r48, "posts"."image_upload_id" AS t0_r49, "topics"."id" AS t1_r0, "topics"."title" AS t1_r1, "topics"."last_posted_at" AS t1_r2, "topics"."created_at" AS t1_r3, "topics"."updated_at" AS t1_r4, "topics"."views" AS t1_r5, "topics"."posts_count" AS t1_r6, "topics"."user_id" AS t1_r7, "topics"."last_post_user_id" AS t1_r8, "topics"."reply_count" AS t1_r9, "topics"."featured_user1_id" AS t1_r10, "topics"."featured_user2_id" AS t1_r11, "topics"."featured_user3_id" AS t1_r12, "topics"."deleted_at" AS t1_r13, "topics"."highest_post_number" AS t1_r14, "topics"."like_count" AS t1_r15, "topics"."incoming_link_count" AS t1_r16, "topics"."category_id" AS t1_r17, "topics"."visible" AS t1_r18, "topics"."moderator_posts_count" AS t1_r19, "topics"."closed" AS t1_r20, "topics"."archived" AS t1_r21, "topics"."bumped_at" AS t1_r22, "topics"."has_summary" AS t1_r23, "topics"."archetype" AS t1_r24, "topics"."featured_user4_id" AS t1_r25, "topics"."notify_moderators_count" AS t1_r26, "topics"."spam_count" AS t1_r27, "topics"."pinned_at" AS t1_r28, "topics"."score" AS t1_r29, "topics"."percent_rank" AS t1_r30, "topics"."subtype" AS t1_r31, "topics"."slug" AS t1_r32, "topics"."deleted_by_id" AS t1_r33, "topics"."participant_count" AS t1_r34, "topics"."word_count" AS t1_r35, "topics"."excerpt" AS t1_r36, "topics"."pinned_globally" AS t1_r37, "topics"."pinned_until" AS t1_r38, "topics"."fancy_title" AS t1_r39, "topics"."highest_staff_post_number" AS t1_r40, "topics"."featured_link" AS t1_r41, "topics"."reviewable_score" AS t1_r42, "topics"."image_upload_id" AS t1_r43, "topics"."slow_mode_seconds" AS t1_r44 FROM "posts" INNER JOIN "topics" ON "topics"."id" = "posts"."topic_id" AND ("topics"."deleted_at" IS NULL) WHERE ("posts"."deleted_at" IS NULL) AND (posts.post_type IN (1,2,3,4)) AND ("topics"."deleted_at" IS NULL) AND (topics.archetype <> 'private_message') AND "topics"."visible" = TRUE AND (topics.category_id IS NULL OR topics.category_id IN (SELECT id FROM categories WHERE NOT read_restricted OR id IN (3,4,5,17,19,25,26,27,28))) AND "posts"."user_id" = 27510 AND (post_number > 1) ORDER BY posts.like_count DESC, posts.created_at DESC LIMIT 6;
SELECT "topic_links"."id" AS t0_r0, "topic_links"."topic_id" AS t0_r1, "topic_links"."post_id" AS t0_r2, "topic_links"."user_id" AS t0_r3, "topic_links"."url" AS t0_r4, "topic_links"."domain" AS t0_r5, "topic_links"."internal" AS t0_r6, "topic_links"."link_topic_id" AS t0_r7, "topic_links"."created_at" AS t0_r8, "topic_links"."updated_at" AS t0_r9, "topic_links"."reflection" AS t0_r10, "topic_links"."clicks" AS t0_r11, "topic_links"."link_post_id" AS t0_r12, "topic_links"."title" AS t0_r13, "topic_links"."crawled_at" AS t0_r14, "topic_links"."quote" AS t0_r15, "topic_links"."extension" AS t0_r16, "topics"."id" AS t1_r0, "topics"."title" AS t1_r1, "topics"."last_posted_at" AS t1_r2, "topics"."created_at" AS t1_r3, "topics"."updated_at" AS t1_r4, "topics"."views" AS t1_r5, "topics"."posts_count" AS t1_r6, "topics"."user_id" AS t1_r7, "topics"."last_post_user_id" AS t1_r8, "topics"."reply_count" AS t1_r9, "topics"."featured_user1_id" AS t1_r10, "topics"."featured_user2_id" AS t1_r11, "topics"."featured_user3_id" AS t1_r12, "topics"."deleted_at" AS t1_r13, "topics"."highest_post_number" AS t1_r14, "topics"."like_count" AS t1_r15, "topics"."incoming_link_count" AS t1_r16, "topics"."category_id" AS t1_r17, "topics"."visible" AS t1_r18, "topics"."moderator_posts_count" AS t1_r19, "topics"."closed" AS t1_r20, "topics"."archived" AS t1_r21, "topics"."bumped_at" AS t1_r22, "topics"."has_summary" AS t1_r23, "topics"."archetype" AS t1_r24, "topics"."featured_user4_id" AS t1_r25, "topics"."notify_moderators_count" AS t1_r26, "topics"."spam_count" AS t1_r27, "topics"."pinned_at" AS t1_r28, "topics"."score" AS t1_r29, "topics"."percent_rank" AS t1_r30, "topics"."subtype" AS t1_r31, "topics"."slug" AS t1_r32, "topics"."deleted_by_id" AS t1_r33, "topics"."participant_count" AS t1_r34, "topics"."word_count" AS t1_r35, "topics"."excerpt" AS t1_r36, "topics"."pinned_globally" AS t1_r37, "topics"."pinned_until" AS t1_r38, "topics"."fancy_title" AS t1_r39, "topics"."highest_staff_post_number" AS t1_r40, "topics"."featured_link" AS t1_r41, "topics"."reviewable_score" AS t1_r42, "topics"."image_upload_id" AS t1_r43, "topics"."slow_mode_seconds" AS t1_r44, "posts"."id" AS t2_r0, "posts"."user_id" AS t2_r1, "posts"."topic_id" AS t2_r2, "posts"."post_number" AS t2_r3, "posts"."raw" AS t2_r4, "posts"."cooked" AS t2_r5, "posts"."created_at" AS t2_r6, "posts"."updated_at" AS t2_r7, "posts"."reply_to_post_number" AS t2_r8, "posts"."reply_count" AS t2_r9, "posts"."quote_count" AS t2_r10, "posts"."deleted_at" AS t2_r11, "posts"."off_topic_count" AS t2_r12, "posts"."like_count" AS t2_r13, "posts"."incoming_link_count" AS t2_r14, "posts"."bookmark_count" AS t2_r15, "posts"."score" AS t2_r16, "posts"."reads" AS t2_r17, "posts"."post_type" AS t2_r18, "posts"."sort_order" AS t2_r19, "posts"."last_editor_id" AS t2_r20, "posts"."hidden" AS t2_r21, "posts"."hidden_reason_id" AS t2_r22, "posts"."notify_moderators_count" AS t2_r23, "posts"."spam_count" AS t2_r24, "posts"."illegal_count" AS t2_r25, "posts"."inappropriate_count" AS t2_r26, "posts"."last_version_at" AS t2_r27, "posts"."user_deleted" AS t2_r28, "posts"."reply_to_user_id" AS t2_r29, "posts"."percent_rank" AS t2_r30, "posts"."notify_user_count" AS t2_r31, "posts"."like_score" AS t2_r32, "posts"."deleted_by_id" AS t2_r33, "posts"."edit_reason" AS t2_r34, "posts"."word_count" AS t2_r35, "posts"."version" AS t2_r36, "posts"."cook_method" AS t2_r37, "posts"."wiki" AS t2_r38, "posts"."baked_at" AS t2_r39, "posts"."baked_version" AS t2_r40, "posts"."hidden_at" AS t2_r41, "posts"."self_edits" AS t2_r42, "posts"."reply_quoted" AS t2_r43, "posts"."via_email" AS t2_r44, "posts"."raw_email" AS t2_r45, "posts"."public_version" AS t2_r46, "posts"."action_code" AS t2_r47, "posts"."locked_by_id" AS t2_r48, "posts"."image_upload_id" AS t2_r49 FROM "topic_links" INNER JOIN "topics" ON "topics"."id" = "topic_links"."topic_id" AND ("topics"."deleted_at" IS NULL) INNER JOIN "posts" ON "posts"."id" = "topic_links"."post_id" AND ("posts"."deleted_at" IS NULL) WHERE "posts"."user_id" = 27510 AND (posts.post_type IN (1,2,3,4)) AND ("topics"."deleted_at" IS NULL) AND (topics.archetype <> 'private_message') AND "topics"."visible" = TRUE AND (topics.category_id IS NULL OR topics.category_id IN (SELECT id FROM categories WHERE NOT read_restricted OR id IN (3,4,5,17,19,25,26,27,28))) AND "topic_links"."user_id" = 27510 AND "topic_links"."internal" = FALSE AND "topic_links"."reflection" = FALSE AND "topic_links"."quote" = FALSE ORDER BY clicks DESC, topic_links.created_at DESC LIMIT 6;
كلاهما يستخدم ذاكرة لملفات مؤقتة، وأوقات التنفيذ جيدة بما يكفي. ربما يكون الأمر مستقرًا؟
أعتقد أن هذا التحليل قد يكون يسحب بيانات مخزنة مؤقتًا. تظهر صفحة الملخص من الموقع أوقات تنفيذ أطول بكثير:
سأحاول إعادة تشغيل التحليل لاحقًا بمجرد انتهاء صلاحية التخزين المؤقت ربما.
يجب أن تعمل إعادة الفهرسة مرة واحدة فقط - بعد أن تكون الفهارس بتنسيق القرص v13، تظل بتنسيق القرص v13.
نعم، إذا لم تتضمن عملية VACUUM التي قمت بها عملية ANALYZE، فأنت تفقد استخدام الفهارس.
إعجابَين (2)
حسنًا، إذن هذا الاستعلام يجلب المنشورات الأكثر إعجابًا لمستخدم معين.
كان التقدير هنا بعيدًا جدًا — فقد قيّم المخطط 2,389 صفًا وحصل على 20,157 صفًا.
مستوى أعلى، تباين آخر بمقدار 5 أضعاف.
هذا هو نوع سوء التقدير الذي سيؤدي إلى أداء رديء للاستعلامات.
إعجابَين (2)
حسنًا، كما أفهم، لم يكن ينبغي أن تكون على أي تنسيق سوى تنسيق القرص v13. لقد استوردنا البيانات من برنامج منتدى آخر إلى تثبيت جديد لـ Discourse كان يعمل بالفعل بإصدار v13. حاليًا، أحاول فقط التأكد من إعادة بناء جميع الفهارس بشكل صحيح بعد الاستيراد.
هذا منطقي. أحاول تشغيل إعادة الفهرسة مرة أخرى بعد زيادة قيمة maintenance_work_mem. يبدو أن postmaster يستخدم الآن ذاكرة أكثر من السابق، لكنني لا زلت لا أعرف ما إذا كان سيكتمل في وقت معقول.
إعجابَين (2)
يبدو أن هناك مهمة شارة قيد التشغيل تعيد الفهرسة.
هل تعمل هذه المهمة منذ أكثر من ساعتين؟ يبدو ذلك غريبًا.
قد يكون هناك شيء في هذه المهمة الأسبوعية لا يزال قيد التشغيل أيضًا:
قد تحتاج إلى تنفيذ الأمر
sv stop unicorn
لإيقاف خادم الويب أثناء إعادة فهرسة قاعدة البيانات.
إعجاب واحد (1)
حسنًا، اكتمل إعادة الفهرسة أخيرًا في وقت معقول. كانت هناك بعض الفهارس التي أفادت بأنها لا تستطيع إعادة بنائها وتخطتها، لكن دون تفاصيل إضافية حول السبب. إليك إحصائيات الجداول الآن:
يبدو أن مشكلة تحميل الملف الشخصي قد ساءت:
إليك نتائج EXPLAIN لتلك الاستعلامات:
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=625609.73..625610.43 rows=6 width=1278) (actual time=2058.211..2154.991 rows=6 loops=1)
-> Gather Merge (cost=625609.73..630928.70 rows=45588 width=1278) (actual time=1654.881..1751.658 rows=6 loops=1)
Workers Planned: 2
Workers Launched: 2
-> Sort (cost=624609.70..624666.69 rows=22794 width=1278) (actual time=1619.464..1619.469 rows=5 loops=3)
Sort Key: posts.like_count DESC, posts.created_at DESC
Sort Method: top-N heapsort Memory: 37kB
Worker 0: Sort Method: top-N heapsort Memory: 37kB
Worker 1: Sort Method: top-N heapsort Memory: 38kB
-> Parallel Hash Join (cost=63000.65..624201.13 rows=22794 width=1278) (actual time=1383.820..1600.913 rows=20578 loops=3)
Hash Cond: (posts.topic_id = topics.id)
-> Parallel Bitmap Heap Scan on posts (cost=1875.97..562899.73 rows=67322 width=783) (actual time=63.310..264.627 rows=20579 loops=3)
Recheck Cond: ((user_id = 7237) AND (deleted_at IS NULL))
Filter: ((post_number > 1) AND (post_type = ANY ('{1,2,3,4}'::integer[])))
Rows Removed by Filter: 39566
Heap Blocks: exact=50390
-> Bitmap Index Scan on idx_posts_user_id_deleted_at (cost=0.00..1835.58 rows=167352 width=0) (actual time=36.507..36.508 rows=180435 loops=1)
Index Cond: (user_id = 7237)
-> Parallel Hash (cost=59504.20..59504.20 rows=129638 width=495) (actual time=1319.362..1319.364 rows=131785 loops=3)
Buckets: 524288 Batches: 1 Memory Usage: 190560kB
-> Parallel Seq Scan on topics (cost=3.81..59504.20 rows=129638 width=495) (actual time=316.007..1204.917 rows=131785 loops=3)
Filter: ((deleted_at IS NULL) AND (deleted_at IS NULL) AND visible AND ((archetype)::text <> 'private_message'::text) AND ((category_id IS NULL) OR (hashed SubPlan 1)))
Rows Removed by Filter: 174529
SubPlan 1
-> Seq Scan on categories (cost=0.00..3.74 rows=28 width=4) (actual time=17.841..17.887 rows=35 loops=3)
Filter: ((NOT read_restricted) OR (id = ANY ('{3,4,5,17,19,25,26,27,28}'::integer[])))
Planning Time: 0.751 ms
JIT:
Functions: 91
Options: Inlining true, Optimization true, Expressions true, Deforming true
Timing: Generation 11.057 ms, Inlining 134.342 ms, Optimization 762.277 ms, Emission 451.708 ms, Total 1359.384 ms
Execution Time: 2204.845 ms
(32 rows)
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=726143.96..726144.66 rows=6 width=1464) (actual time=5250.325..5305.144 rows=6 loops=1)
-> Gather Merge (cost=726143.96..726351.17 rows=1776 width=1464) (actual time=4800.064..4854.881 rows=6 loops=1)
Workers Planned: 2
Workers Launched: 2
-> Sort (cost=725143.93..725146.15 rows=888 width=1464) (actual time=4762.610..4762.615 rows=5 loops=3)
Sort Key: topic_links.clicks DESC, topic_links.created_at DESC
Sort Method: top-N heapsort Memory: 36kB
Worker 0: Sort Method: top-N heapsort Memory: 37kB
Worker 1: Sort Method: top-N heapsort Memory: 32kB
-> Nested Loop (cost=574851.64..725128.02 rows=888 width=1464) (actual time=649.373..4710.853 rows=39385 loops=3)
-> Parallel Hash Join (cost=574847.40..695445.64 rows=2624 width=969) (actual time=630.974..3847.821 rows=336541 loops=3)
Hash Cond: (topic_links.post_id = posts.id)
-> Parallel Bitmap Heap Scan on topic_links (cost=11248.93..130753.84 rows=416505 width=186) (actual time=58.964..3095.540 rows=336541 loops=3)
Recheck Cond: (user_id = 7237)
Filter: ((NOT internal) AND (NOT reflection) AND (NOT quote))
Rows Removed by Filter: 8
Heap Blocks: exact=23544
-> Bitmap Index Scan on index_topic_links_on_user_id (cost=0.00..10999.02 rows=1000879 width=0) (actual time=45.320..45.322 rows=1009648 loops=1)
Index Cond: (user_id = 7237)
-> Parallel Hash (cost=562726.85..562726.85 rows=69730 width=783) (actual time=571.264..571.266 rows=60145 loops=3)
Buckets: 262144 Batches: 1 Memory Usage: 71264kB
-> Parallel Bitmap Heap Scan on posts (cost=1877.42..562726.85 rows=69730 width=783) (actual time=377.440..481.561 rows=60145 loops=3)
Recheck Cond: ((user_id = 7237) AND (deleted_at IS NULL))
Filter: (post_type = ANY ('{1,2,3,4}'::integer[]))
Heap Blocks: exact=141396
-> Bitmap Index Scan on idx_posts_user_id_deleted_at (cost=0.00..1835.58 rows=167352 width=0) (actual time=29.225..29.226 rows=180435 loops=1)
Index Cond: (user_id = 7237)
-> Index Scan using topics_pkey on topics (cost=4.24..11.31 rows=1 width=495) (actual time=0.002..0.002 rows=0 loops=1009624)
Index Cond: (id = topic_links.topic_id)
Filter: ((deleted_at IS NULL) AND (deleted_at IS NULL) AND visible AND ((archetype)::text <> 'private_message'::text) AND ((category_id IS NULL) OR (hashed SubPlan 1)))
Rows Removed by Filter: 1
SubPlan 1
-> Seq Scan on categories (cost=0.00..3.74 rows=28 width=4) (actual time=17.793..17.835 rows=35 loops=3)
Filter: ((NOT read_restricted) OR (id = ANY ('{3,4,5,17,19,25,26,27,28}'::integer[])))
Planning Time: 4.526 ms
JIT:
Functions: 118
Options: Inlining true, Optimization true, Expressions true, Deforming true
Timing: Generation 14.724 ms, Inlining 94.921 ms, Optimization 934.359 ms, Emission 525.383 ms, Total 1569.387 ms
Execution Time: 5309.478 ms
(40 rows)
لقد أضفت الفهارس التي توصلت إليها سابقًا للمساعدة في هذه المشكلة (Slow Page Loads on User Profiles - #2 by Ghan)، وقد أدى ذلك إلى تقليل أوقات التحميل بشكل كبير.
خطة الاستعلام بعد إضافة الفهارس:
QUERY PLAN
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=1004.13..25136.02 rows=6 width=1473) (actual time=84.592..96.171 rows=6 loops=1)
-> Gather Merge (cost=1004.13..9649737.42 rows=2399 width=1473) (actual time=84.591..96.168 rows=6 loops=1)
Workers Planned: 2
Workers Launched: 2
-> Nested Loop (cost=4.11..9648460.49 rows=1000 width=1473) (actual time=60.452..60.471 rows=4 loops=3)
-> Nested Loop (cost=0.87..9619828.27 rows=2943 width=977) (actual time=0.115..47.798 rows=6058 loops=3)
-> Parallel Index Scan using index_topic_links_on_clicks_and_created_desc on topic_links (cost=0.43..6728256.06 rows=403188 width=186) (actual time=0.051..30.428 rows=6058 loops=3)
Filter: ((NOT internal) AND (NOT reflection) AND (NOT quote) AND (user_id = 7237))
Rows Removed by Filter: 54345
-> Index Scan using posts_pkey on posts (cost=0.44..7.17 rows=1 width=791) (actual time=0.002..0.002 rows=1 loops=18173)
Index Cond: (id = topic_links.post_id)
Filter: ((deleted_at IS NULL) AND (user_id = 7237) AND (post_type = ANY ('{1,2,3,4}'::integer[])))
-> Index Scan using topics_pkey on topics (cost=3.24..9.73 rows=1 width=496) (actual time=0.002..0.002 rows=0 loops=18173)
Index Cond: (id = topic_links.topic_id)
Filter: ((deleted_at IS NULL) AND (deleted_at IS NULL) AND visible AND ((archetype)::text <> 'private_message'::text) AND ((category_id IS NULL) OR (hashed SubPlan 1)))
Rows Removed by Filter: 1
SubPlan 1
-> Seq Scan on categories (cost=0.00..2.74 rows=28 width=4) (actual time=0.031..0.049 rows=35 loops=3)
Filter: ((NOT read_restricted) OR (id = ANY ('{3,4,5,17,19,25,26,27,28}'::integer[])))
Planning Time: 1.205 ms
Execution Time: 96.258 ms
(21 rows)
إليك الفهارس في حال أراد أي شخص إضافتها:
CREATE INDEX index_topic_links_on_clicks_and_created ON public.topic_links USING btree (clicks, created_at);
CREATE INDEX index_posts_on_like_count_and_created ON public.posts USING btree (like_count, created_at);
CREATE INDEX index_topic_links_on_clicks_and_created_desc ON public.topic_links USING btree (clicks DESC, created_at DESC);
CREATE INDEX index_posts_on_like_count_and_created_desc ON public.posts USING btree (like_count DESC, created_at DESC, user_id) WHERE deleted_at IS NULL AND post_number > 1 AND (post_type = ANY ('{1,2,3,4}'::integer[]));
إعجاب واحد (1)
هنا وهنا سألت عما إذا كانت هذه الفهارس مفقودة. مجرد إضافة هذه الفهارس يُحدث فرقًا هائلاً في سرعة تحميل الملفات الشخصية. يجب بالتأكيد النظر في هذه الفهارس.
من الصحيح أن ذاكرة التخزين المؤقت المضافة هنا: Slow Page Loads on User Profiles - #12 by codinghorror أحدثت فرقًا كبيرًا، لكن هذا ينطبق فقط على التحميلات اللاحقة، بينما تحسّن الفهارس التجربة الأولية بشكل عام. لا ينبغي تعريض المستخدمين لأوقات تحميل بطيئة حتى لو تحسنت لاحقًا بفضل ذاكرة التخزين المؤقت خلال الفترة التي تكون فيها البيانات مخزنة. كان الهدف تحسين التحميل الأولي (عند انتهاء صلاحية ذاكرة التخزين المؤقت)، وهذا الإنجاز يحقق ذلك بشكل كبير.
4 إعجابات
أنا غير واضح حول كيفية ضرورة وجود فهرس في كل صف مفرد مرتب حسب عدد النقرات/عدد الإعجابات لصفحة مستخدم محصورة بمعرف مستخدم واحد.
إعجابَين (2)
بخصوص النقرات، يبدو في حالتنا أن المكسب الرئيسي يكمن هنا:
-> Sort (cost=725143.93..725146.15 rows=888 width=1464) (actual time=4762.610..4762.615 rows=5 loops=3)
Sort Key: topic_links.clicks DESC, topic_links.created_at DESC
تستغرق عملية الفرز هذه 4 ثوانٍ، وهو ما يفسر جزئيًا سبب بطء تحميل الصفحات الشخصية. هذه مجرد استعلام واحد من بين العديد في صفحة الملف الشخصي (وإن كان أحد أكثر الاستعلامات تكلفة من حيث السرعة). بعد إضافة الفهرس، يلتقط مخطط الاستعلامه هنا، مما يقلل وقت تنفيذ الاستعلام لهذا الفرع إلى حوالي 30 مللي ثانية:
-> Parallel Index Scan using index_topic_links_on_clicks_and_created_desc on topic_links (cost=0.43..6728256.06 rows=403188 width=186) (actual time=0.051..30.428 rows=6058 loops=3)
من الواضح أن خطة الاستعلام تتغير بطرق أخرى أيضًا، لكن الفهرس يُستشهد به بالتأكيد هنا، مما يجعل تنفيذ الاستعلام أسرع بكثير.
إعجاب واحد (1)
لكن من الناحية المفاهيمية، كل ما نهتم به هو الروابط المحددة بالنطاق الخاص بالمستخدم، فلماذا لا تكون الفهارس المقترحة الجديدة محدودة بالنطاق الخاص بالمستخدمين؟
إعجاب واحد (1)