Add better indexes and delete redundant ones.

utilities/database_upgrader.py

@@ -154,10 +154,31 @@ def upgrade_6_to_7(ycdldb):
     ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_author_download')
     ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_download')
     ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_download_published')
-    ycdldb.sql.execute('CREATE INDEX index_video_author_state on videos(author_id, state)')
+    # /videos/state?orderby=published
-    ycdldb.sql.execute('CREATE INDEX index_video_state on videos(state)')
     ycdldb.sql.execute('CREATE INDEX index_video_state_published on videos(state, published)')
 
+def upgrade_7_to_8(ycdldb):
+    '''
+    In this version, indexes were optimized by adding indexes that satisfy the
+    major use cases, and deleting indexes that are redundant in the presence of
+    another multi-column index.
+    '''
+    # /channel?orderby=published
+    ycdldb.sql.execute('''
+        CREATE INDEX IF NOT EXISTS index_video_author_published on videos(author_id, published);
+    ''')
+    # /channel/state?orderby=published
+    ycdldb.sql.execute('''
+        CREATE INDEX IF NOT EXISTS index_video_author_state_published
+        on videos(author_id, state, published);
+    ''')
+    # Redundant due to (author, published)
+    ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_author')
+    # Redundant due to (author, state, published)
+    ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_author_state')
+    # Redundant due to (state, published)
+    ycdldb.sql.execute('DROP INDEX IF EXISTS index_video_state')
+
 def upgrade_all(data_directory):
     '''
     Given the directory containing a ycdl database, apply all of the

ycdl/constants.py

@@ -1,6 +1,6 @@
 from voussoirkit import sqlhelpers
 
-DATABASE_VERSION = 7
+DATABASE_VERSION = 8
 DB_VERSION_PRAGMA = f'''
 PRAGMA user_version = {DATABASE_VERSION};
 '''
@@ -36,11 +36,10 @@ CREATE TABLE IF NOT EXISTS videos(
 );
 
 CREATE INDEX IF NOT EXISTS index_channel_id on channels(id);
-CREATE INDEX IF NOT EXISTS index_video_author on videos(author_id);
+CREATE INDEX IF NOT EXISTS index_video_author_published on videos(author_id, published);
-CREATE INDEX IF NOT EXISTS index_video_author_state on videos(author_id, state);
+CREATE INDEX IF NOT EXISTS index_video_author_state_published on videos(author_id, state, published);
 CREATE INDEX IF NOT EXISTS index_video_id on videos(id);
 CREATE INDEX IF NOT EXISTS index_video_published on videos(published);
-CREATE INDEX IF NOT EXISTS index_video_state on videos(state);
 CREATE INDEX IF NOT EXISTS index_video_state_published on videos(state, published);
 ----------------------------------------------------------------------------------------------------
 COMMIT;