SQLAlchemy ORM によって生成されたクエリがあります。特定のコースの stream_items を、そのすべての部分 (リソース、コンテンツ テキスト ブロックなど)、およびそれらを投稿したユーザーと共に取得することになっています。ただし、このクエリは非常に遅いようで、データベースに 20,000 人程度のユーザーがいて、コースに 25 程度の stream_items があり、stream_item ごとにいくつかのコンテンツ テキスト ブロックがある実稼働データベースでは数分かかります。多数のユーザーをインポートしましたが、コンテンツはほとんどないため、データベースにはユーザー以外のレコードがほとんどないことに注意してください。
編集: すべてのオブジェクト ID は franklin_object テーブルへの外部キーであることに注意してください。
私はクエリを調べてみましたが、いくつかの厄介なビットを特定しました (EXPLAIN 出力を見てください)。
- ルックアップの 1 つは、'Using temporary;' です。ファイルソート」を使用します。
- インデックスなしでユーザー テーブルが 2 回ヒットする
- インデックスなしでコンテンツ テキスト ブロック テーブルが 2 回ヒットする
しかし、特に後者の 2 つの問題については、どうすればよいかわかりません。
クエリは次のとおりです。
SELECT stream_item.id AS stream_item_id,
franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
stream_item.parent_id AS stream_item_parent_id,
stream_item.shown_at AS stream_item_shown_at,
stream_item.author_id AS stream_item_author_id,
stream_item.stream_sort_at AS stream_item_stream_sort_at,
stream_item.PUBLIC AS stream_item_public,
stream_item.created_at AS stream_item_created_at,
stream_item.updated_at AS stream_item_updated_at,
anon_1.content_text_block_text AS anon_1_content_text_block_text,
anon_2.resource_id AS anon_2_resource_id,
anon_2.franklin_object_id AS anon_2_franklin_object_id,
anon_2.franklin_object_type AS anon_2_franklin_object_type,
anon_2.franklin_object_uuid AS anon_2_franklin_object_uuid,
anon_2.resource_top_parent_resource AS anon_2_resource_top_parent_resource,
anon_2.resource_top_parent_id AS anon_2_resource_top_parent_id,
anon_2.resource_title AS anon_2_resource_title,
anon_2.resource_url AS anon_2_resource_url,
anon_2.resource_image AS anon_2_resource_image,
anon_2.resource_created_at AS anon_2_resource_created_at,
anon_2.resource_updated_at AS anon_2_resource_updated_at,
franklin_object_1.id AS franklin_object_1_id,
franklin_object_1.type AS franklin_object_1_type,
franklin_object_1.uuid AS franklin_object_1_uuid,
anon_1.content_text_block_id AS anon_1_content_text_block_id,
anon_1.franklin_object_id AS anon_1_franklin_object_id,
anon_1.franklin_object_type AS anon_1_franklin_object_type,
anon_1.franklin_object_uuid AS anon_1_franklin_object_uuid,
anon_1.content_text_block_position AS anon_1_content_text_block_position,
anon_1.content_text_block_franklin_object_id AS anon_1_content_text_block_franklin_object_id,
anon_1.content_text_block_created_at AS anon_1_content_text_block_created_at,
anon_1.content_text_block_updated_at AS anon_1_content_text_block_updated_at,
anon_3.user_password AS anon_3_user_password,
anon_3.user_auth_token AS anon_3_user_auth_token,
anon_3.user_id AS anon_3_user_id,
anon_3.franklin_object_id AS anon_3_franklin_object_id,
anon_3.franklin_object_type AS anon_3_franklin_object_type,
anon_3.franklin_object_uuid AS anon_3_franklin_object_uuid,
anon_3.user_email AS anon_3_user_email,
anon_3.user_auth_token_expiration AS anon_3_user_auth_token_expiration,
anon_3.user_active AS anon_3_user_active,
anon_3.user_activation_token AS anon_3_user_activation_token,
anon_3.user_first_name AS anon_3_user_first_name,
anon_3.user_last_name AS anon_3_user_last_name,
anon_3.user_image AS anon_3_user_image,
anon_3.user_bio AS anon_3_user_bio,
anon_3.user_aspirations AS anon_3_user_aspirations,
anon_3.user_website AS anon_3_user_website,
anon_3.user_resume AS anon_3_user_resume,
anon_3.user_resume_name AS anon_3_user_resume_name,
anon_3.user_primary_role AS anon_3_user_primary_role,
anon_3.user_institution_id AS anon_3_user_institution_id,
anon_3.user_birth_date AS anon_3_user_birth_date,
anon_3.user_gender AS anon_3_user_gender,
anon_3.user_graduation_year AS anon_3_user_graduation_year,
anon_3.user_complete AS anon_3_user_complete,
anon_3.user_masthead_y_position AS anon_3_user_masthead_y_position,
anon_3.user_masthead AS anon_3_user_masthead,
anon_3.user_fb_access_token AS anon_3_user_fb_access_token,
anon_3.user_fb_user_id AS anon_3_user_fb_user_id,
anon_3.user_location AS anon_3_user_location,
anon_3.user_created_at AS anon_3_user_created_at,
anon_3.user_updated_at AS anon_3_user_updated_at,
anon_4.content_text_block_text AS anon_4_content_text_block_text,
anon_4.content_text_block_id AS anon_4_content_text_block_id,
anon_4.franklin_object_id AS anon_4_franklin_object_id,
anon_4.franklin_object_type AS anon_4_franklin_object_type,
anon_4.franklin_object_uuid AS anon_4_franklin_object_uuid,
anon_4.content_text_block_position AS anon_4_content_text_block_position,
anon_4.content_text_block_franklin_object_id AS anon_4_content_text_block_franklin_object_id,
anon_4.content_text_block_created_at AS anon_4_content_text_block_created_at,
anon_4.content_text_block_updated_at AS anon_4_content_text_block_updated_at,
anon_5.user_password AS anon_5_user_password,
anon_5.user_auth_token AS anon_5_user_auth_token,
anon_5.user_id AS anon_5_user_id,
anon_5.franklin_object_id AS anon_5_franklin_object_id,
anon_5.franklin_object_type AS anon_5_franklin_object_type,
anon_5.franklin_object_uuid AS anon_5_franklin_object_uuid,
anon_5.user_email AS anon_5_user_email,
anon_5.user_auth_token_expiration AS anon_5_user_auth_token_expiration,
anon_5.user_active AS anon_5_user_active,
anon_5.user_activation_token AS anon_5_user_activation_token,
anon_5.user_first_name AS anon_5_user_first_name,
anon_5.user_last_name AS anon_5_user_last_name,
anon_5.user_image AS anon_5_user_image,
anon_5.user_bio AS anon_5_user_bio,
anon_5.user_aspirations AS anon_5_user_aspirations,
anon_5.user_website AS anon_5_user_website,
anon_5.user_resume AS anon_5_user_resume,
anon_5.user_resume_name AS anon_5_user_resume_name,
anon_5.user_primary_role AS anon_5_user_primary_role,
anon_5.user_institution_id AS anon_5_user_institution_id,
anon_5.user_birth_date AS anon_5_user_birth_date,
anon_5.user_gender AS anon_5_user_gender,
anon_5.user_graduation_year AS anon_5_user_graduation_year,
anon_5.user_complete AS anon_5_user_complete,
anon_5.user_masthead_y_position AS anon_5_user_masthead_y_position,
anon_5.user_masthead AS anon_5_user_masthead,
anon_5.user_fb_access_token AS anon_5_user_fb_access_token,
anon_5.user_fb_user_id AS anon_5_user_fb_user_id,
anon_5.user_location AS anon_5_user_location,
anon_5.user_created_at AS anon_5_user_created_at,
anon_5.user_updated_at AS anon_5_user_updated_at,
anon_6.stream_item_id AS anon_6_stream_item_id,
anon_6.franklin_object_id AS anon_6_franklin_object_id,
anon_6.franklin_object_type AS anon_6_franklin_object_type,
anon_6.franklin_object_uuid AS anon_6_franklin_object_uuid,
anon_6.stream_item_parent_id AS anon_6_stream_item_parent_id,
anon_6.stream_item_shown_at AS anon_6_stream_item_shown_at,
anon_6.stream_item_author_id AS anon_6_stream_item_author_id,
anon_6.stream_item_stream_sort_at AS anon_6_stream_item_stream_sort_at,
anon_6.stream_item_public AS anon_6_stream_item_public,
anon_6.stream_item_created_at AS anon_6_stream_item_created_at,
anon_6.stream_item_updated_at AS anon_6_stream_item_updated_at
FROM franklin_object
INNER JOIN stream_item
ON franklin_object.id = stream_item.id
INNER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
content_text_block.id AS content_text_block_id,
content_text_block.text AS content_text_block_text,
content_text_block.position AS content_text_block_position,
content_text_block.franklin_object_id AS content_text_block_franklin_object_id,
content_text_block.created_at AS content_text_block_created_at,
content_text_block.updated_at AS content_text_block_updated_at
FROM franklin_object
INNER JOIN content_text_block
ON franklin_object.id = content_text_block.id) AS anon_1
ON stream_item.id = anon_1.content_text_block_franklin_object_id
LEFT OUTER JOIN contents_resources AS contents_resources_1
ON anon_1.content_text_block_id = contents_resources_1.content_id
LEFT OUTER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
resource.id AS resource_id,
resource.top_parent_resource AS resource_top_parent_resource,
resource.top_parent_id AS resource_top_parent_id,
resource.title AS resource_title,
resource.url AS resource_url,
resource.image AS resource_image,
resource.created_at AS resource_created_at,
resource.updated_at AS resource_updated_at
FROM franklin_object
INNER JOIN resource
ON franklin_object.id = resource.id) AS anon_2
ON anon_2.resource_id = contents_resources_1.resource_id
LEFT OUTER JOIN contents_franklin_objects AS contents_franklin_objects_1
ON anon_1.content_text_block_id = contents_franklin_objects_1.content_id
LEFT OUTER JOIN franklin_object AS franklin_object_1
ON franklin_object_1.id = contents_franklin_objects_1.franklin_object_id
LEFT OUTER JOIN likers AS likers_1
ON stream_item.id = likers_1.post_id
LEFT OUTER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
USER.id AS user_id,
USER.email AS user_email,
USER.password AS user_password,
USER.auth_token AS user_auth_token,
USER.auth_token_expiration AS user_auth_token_expiration,
USER.active AS user_active,
USER.activation_token AS user_activation_token,
USER.first_name AS user_first_name,
USER.last_name AS user_last_name,
USER.image AS user_image,
USER.bio AS user_bio,
USER.aspirations AS user_aspirations,
USER.website AS user_website,
USER.resume AS user_resume,
USER.resume_name AS user_resume_name,
USER.primary_role AS user_primary_role,
USER.institution_id AS user_institution_id,
USER.birth_date AS user_birth_date,
USER.gender AS user_gender,
USER.graduation_year AS user_graduation_year,
USER.complete AS user_complete,
USER.masthead_y_position AS user_masthead_y_position,
USER.masthead AS user_masthead,
USER.fb_access_token AS user_fb_access_token,
USER.fb_user_id AS user_fb_user_id,
USER.location AS user_location,
USER.created_at AS user_created_at,
USER.updated_at AS user_updated_at
FROM franklin_object
INNER JOIN USER
ON franklin_object.id = USER.id) AS anon_3
ON anon_3.user_id = likers_1.user_id
LEFT OUTER JOIN contents_franklin_objects AS contents_franklin_objects_2
ON franklin_object.id = contents_franklin_objects_2.franklin_object_id
LEFT OUTER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
content_text_block.id AS content_text_block_id,
content_text_block.text AS content_text_block_text,
content_text_block.position AS content_text_block_position,
content_text_block.franklin_object_id AS content_text_block_franklin_object_id,
content_text_block.created_at AS content_text_block_created_at,
content_text_block.updated_at AS content_text_block_updated_at
FROM franklin_object
INNER JOIN content_text_block
ON franklin_object.id = content_text_block.id) AS anon_4
ON anon_4.content_text_block_id = contents_franklin_objects_2.content_id
LEFT OUTER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
stream_item.id AS stream_item_id,
stream_item.parent_id AS stream_item_parent_id,
stream_item.shown_at AS stream_item_shown_at,
stream_item.author_id AS stream_item_author_id,
stream_item.stream_sort_at AS stream_item_stream_sort_at,
stream_item.PUBLIC AS stream_item_public,
stream_item.created_at AS stream_item_created_at,
stream_item.updated_at AS stream_item_updated_at
FROM franklin_object
INNER JOIN stream_item
ON franklin_object.id = stream_item.id) AS anon_6
ON anon_6.stream_item_parent_id = franklin_object.id
LEFT OUTER JOIN likers AS likers_2
ON anon_6.stream_item_id = likers_2.post_id
LEFT OUTER JOIN (SELECT franklin_object.id AS franklin_object_id,
franklin_object.type AS franklin_object_type,
franklin_object.uuid AS franklin_object_uuid,
USER.id AS user_id,
USER.email AS user_email,
USER.password AS user_password,
USER.auth_token AS user_auth_token,
USER.auth_token_expiration AS user_auth_token_expiration,
USER.active AS user_active,
USER.activation_token AS user_activation_token,
USER.first_name AS user_first_name,
USER.last_name AS user_last_name,
USER.image AS user_image,
USER.bio AS user_bio,
USER.aspirations AS user_aspirations,
USER.website AS user_website,
USER.resume AS user_resume,
USER.resume_name AS user_resume_name,
USER.primary_role AS user_primary_role,
USER.institution_id AS user_institution_id,
USER.birth_date AS user_birth_date,
USER.gender AS user_gender,
USER.graduation_year AS user_graduation_year,
USER.complete AS user_complete,
USER.masthead_y_position AS user_masthead_y_position,
USER.masthead AS user_masthead,
USER.fb_access_token AS user_fb_access_token,
USER.fb_user_id AS user_fb_user_id,
USER.location AS user_location,
USER.created_at AS user_created_at,
USER.updated_at AS user_updated_at
FROM franklin_object
INNER JOIN USER
ON franklin_object.id = USER.id) AS anon_5
ON anon_5.user_id = likers_2.user_id
WHERE stream_item.parent_id = 11
ORDER BY stream_item.stream_sort_at DESC,
anon_1.content_text_block_position,
anon_6.stream_item_stream_sort_at DESC
EXPLAIN 出力:
ID SELECT_TYPE TABLE POSSIBLY_KEYS KEY KEY_LEN REF ROWS EXTRA
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 599 Using temporary; Using filesort
1 PRIMARY stream_item eq_ref PRIMARY,parent_id PRIMARY 4 anon_1.content_text_block_franklin_object_id 1 Using where
1 PRIMARY contents_resources_1 ref content_id content_id 5 anon_1.content_text_block_id 2
1 PRIMARY <derived3> ALL NULL NULL NULL NULL 7
1 PRIMARY contents_franklin_objects_1 ref content_id content_id 5 anon_1.content_text_block_id 1
1 PRIMARY franklin_object eq_ref PRIMARY PRIMARY 4 franklin.stream_item.id 1 Using where
1 PRIMARY franklin_object_1 eq_ref PRIMARY PRIMARY 4 franklin.contents_franklin_objects_1.franklin_object_id 1
1 PRIMARY likers_1 ref post_id post_id 5 franklin.stream_item.id 1
1 PRIMARY <derived4> ALL NULL NULL NULL NULL 136
1 PRIMARY contents_franklin_objects_2 ref franklin_object_id franklin_object_id 5 franklin.stream_item.id 1
1 PRIMARY <derived5> ALL NULL NULL NULL NULL 599
1 PRIMARY <derived6> ALL NULL NULL NULL NULL 608
1 PRIMARY likers_2 ref post_id post_id 5 anon_6.stream_item_id 1
1 PRIMARY <derived7> ALL NULL NULL NULL NULL 136
7 DERIVED user ALL PRIMARY NULL NULL NULL 133
7 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.user.id 1
6 DERIVED stream_item ALL PRIMARY NULL NULL NULL 709
6 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.stream_item.id 1
5 DERIVED content_text_block ALL PRIMARY NULL NULL NULL 666
5 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.content_text_block.id 1
4 DERIVED user ALL PRIMARY NULL NULL NULL 133
4 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.user.id 1
3 DERIVED resource ALL PRIMARY NULL NULL NULL 7
3 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.resource.id 1
2 DERIVED content_text_block ALL PRIMARY NULL NULL NULL 666
2 DERIVED franklin_object eq_ref PRIMARY PRIMARY 4 franklin.content_text_block.id 1
ALLクエリをより高速なものに減らすにはどうすればよいですか? これを高速化する他の方法は何ですか?
franklin_objects の設定方法はアンチパターンですか? franklin_object テーブルには id と type の 2 つの列があります。次に、各タイプはテーブルであり、主キーは franklin_object への外部キーです。
SQL を生成するコードは、次のようなものです。
stream_item_query = StreamItem.query.options(db.joinedload('stream_items'),db.joinedload('contents_included_in'),db.joinedload('contents.resources'),db.joinedload('contents.objects'),db.subqueryload('likers'))
stream_items = stream_item_query.filter(StreamItem.parent_id == community_id).order_by(db.desc(StreamItem.stream_sort_at)).all()