Add indices for HistoryAtimeIndex and CompletionHistoryAtimeIndex

before
------

sqlite> SELECT * FROM History where not redirect and not url like "qute://%" and atime > ? and atime <= ? ORDER BY atime desc;
Run Time: real 0.072 user 0.063334 sys 0.010000

sqlite> explain query plan SELECT * FROM History where not redirect and not url like "qute://%" and atime > ? and atime <= ? ORDER BY atime desc;
0|0|0|SCAN TABLE History
0|0|0|USE TEMP B-TREE FOR ORDER BY

sqlite> explain query plan select url, title, strftime('%Y-%m-%d', last_atime, 'unixepoch') from CompletionHistory where (url like "%qute%" or title like "%qute%") order by last_atime desc;
0|0|0|SCAN TABLE CompletionHistory
0|0|0|USE TEMP B-TREE FOR ORDER BY

after
-----

sqlite> SELECT * FROM History where not redirect and not url like "qute://%" and atime > ? and atime <= ? ORDER BY atime desc;
Run Time: real 0.000 user 0.000000 sys 0.000000

sqlite> explain query plan SELECT * FROM History where not redirect and not url like "qute://%" and atime > ? and atime <= ? ORDER BY atime desc;
0|0|0|SEARCH TABLE History USING INDEX AtimeIndex (atime>? AND atime<?)

sqlite> explain query plan select url, title, strftime('%Y-%m-%d', last_atime, 'unixepoch') from CompletionHistory where (url like "%qute%" or title like "%qute%") order by last_atime desc;
0|0|0|SCAN TABLE CompletionHistory USING INDEX CompletionAtimeIndex

qutebrowser/browser/history.py

@@ -79,6 +79,7 @@ class CompletionHistory(sql.SqlTable):
     def __init__(self, parent=None):
         super().__init__("CompletionHistory", ['url', 'title', 'last_atime'],
                          constraints={'url': 'PRIMARY KEY'}, parent=parent)
+        self.create_index('CompletionHistoryAtimeIndex', 'last_atime')
 
 
 class WebHistory(sql.SqlTable):
@@ -90,6 +91,7 @@ def __init__(self, parent=None):
                          parent=parent)
         self.completion = CompletionHistory(parent=self)
         self.create_index('HistoryIndex', 'url')
+        self.create_index('HistoryAtimeIndex', 'atime')
         self._contains_query = self.contains_query('url')
         self._between_query = sql.Query('SELECT * FROM History '
                                         'where not redirect '