FTS speedup

src/tribler/core/components/metadata_store/db/store.py

@@ -579,7 +579,7 @@ def torrent_exists_in_personal_channel(self, infohash):
         )
 
     # pylint: disable=unused-argument
-    def search_keyword(self, query):
+    def search_keyword(self, query, origin_id=None):
         # Requires FTS5 table "FtsIndex" to be generated and populated.
         # FTS table is maintained automatically by SQL triggers.
         # BM25 ranking is embedded in FTS5.
@@ -588,16 +588,44 @@ def search_keyword(self, query):
         if not query or query == "*":
             return []
 
-        fts_ids = raw_sql("""
-            SELECT fts.rowid
-            FROM (
-                SELECT rowid FROM FtsIndex WHERE FtsIndex MATCH $query ORDER BY rowid DESC LIMIT 10000
-            ) fts
-            LEFT JOIN ChannelNode cn on fts.rowid = cn.rowid
-            LEFT JOIN main.TorrentState ts on cn.health = ts.rowid
-            ORDER BY coalesce(ts.seeders, 0) DESC, fts.rowid DESC  
-            LIMIT 1000
-        """)
+        if origin_id is not None:
+            # When filtering a specific channel folder, we want to return all matching results
+            fts_ids = raw_sql("""
+                SELECT rowid FROM ChannelNode
+                WHERE origin_id = $origin_id
+                  AND rowid IN (SELECT rowid FROM FtsIndex WHERE FtsIndex MATCH $query)
+            """)
+        else:
+            # When searching through an entire database for some text queries, the database can contain hundreds
+            # of thousands of matching torrents. The ranking of this number of torrents may be very expensive: we need
+            # to retrieve each matching torrent info and the torrent state from the database for proper ordering.
+            # They are scattered randomly through the entire database file, so fetching all these torrents is slow.
+            # Also, the torrent_rank function used inside the final ORDER BY section is written in Python. It is about
+            # 30 times slower than a possible similar function written in C due to SQLite-Python communication cost.
+            #
+            # To speed up the query, we limit and filter search results in several iterations, and each time apply
+            # a more expensive ranking algorithm:
+            #   * First, we quickly fetch at most 10000 of the most recent torrents that match the search criteria
+            #     and ignore older torrents. This way, we avoid sorting all hundreds of thousands of matching torrents
+            #     in degenerative cases. In typical cases, when the text query is specific enough, the number of
+            #     matching torrents is not that big.
+            #   * Then, we sort these 10000 torrents to prioritize torrents with seeders and restrict the number
+            #     of torrents to just 1000.
+            #   * Finally, in the main query, we apply a slow ranking function to these 1000 torrents to show the most
+            #     relevant torrents at the top of the search result list.
+            #
+            # This multistep sort+limit sequence allows speedup queries up to two orders of magnitude. To further
+            # speed up full-text search queries, we can rewrite the torrent_rank function to C one day.
+            fts_ids = raw_sql("""
+                SELECT fts.rowid
+                FROM (
+                    SELECT rowid FROM FtsIndex WHERE FtsIndex MATCH $query ORDER BY rowid DESC LIMIT 10000
+                ) fts
+                LEFT JOIN ChannelNode cn on fts.rowid = cn.rowid
+                LEFT JOIN main.TorrentState ts on cn.health = ts.rowid
+                ORDER BY coalesce(ts.seeders, 0) DESC, fts.rowid DESC  
+                LIMIT 1000
+            """)
         return left_join(g for g in self.MetadataNode if g.rowid in fts_ids)  # pylint: disable=E1135
 
     @db_session
@@ -633,7 +661,12 @@ def get_entries_query(
 
         if cls is None:
             cls = self.ChannelNode
-        pony_query = self.search_keyword(txt_filter) if txt_filter else left_join(g for g in cls)
+
+        if txt_filter:
+            pony_query = self.search_keyword(txt_filter, origin_id=origin_id)
+        else:
+            pony_query = left_join(g for g in cls)
+
         infohash_set = infohash_set or ({infohash} if infohash else None)
         if popular:
             if metadata_type != REGULAR_TORRENT:

src/tribler/core/components/metadata_store/restapi/tests/test_search_endpoint.py

@@ -147,21 +147,21 @@ async def test_search_with_space(rest_api, metadata_store):
         metadata_store.TorrentMetadata(title='abc defxyz', infohash=random_infohash())
 
     s1 = to_fts_query("abc")
-    assert s1 == '"abc"*'
+    assert s1 == '"abc"'
 
     s2 = to_fts_query("abc def")
-    assert s2 == '"abc" "def"*'
+    assert s2 == '"abc" "def"'
 
     ss2 = to_fts_query(s2)
     assert ss2 == s2
 
     parsed = await do_request(rest_api, f'search?txt_filter={s1}', expected_code=200)
     results = {item["name"] for item in parsed["results"]}
-    assert results == {'abc', 'abc.def', 'abc def', 'abc defxyz', 'abcxyz def'}
+    assert results == {'abc', 'abc.def', 'abc def', 'abc defxyz'}
 
     parsed = await do_request(rest_api, f'search?txt_filter={s2}', expected_code=200)
     results = {item["name"] for item in parsed["results"]}
-    assert results == {'abc.def', 'abc def', 'abc defxyz'}  # but not 'abcxyz def'
+    assert results == {'abc.def', 'abc def'}  # but not 'abcxyz def'
 
 
 async def test_single_snippet_in_search(rest_api, metadata_store, knowledge_db):

src/tribler/core/components/metadata_store/utils.py

@@ -86,16 +86,16 @@ def _add_operation(_obj, _op, _key, _predicate=ResourceType.TAG):
 
 
 @db_session
-def generate_torrent(metadata_store, tags_db, parent):
+def generate_torrent(metadata_store, tags_db, parent, title=None):
     infohash = random_infohash()
 
     # Give each torrent some health information. For now, we assume all torrents are healthy.
     now = int(time.time())
     last_check = now - random.randint(3600, 24 * 3600)
     category = random.choice(["Video", "Audio", "Documents", "Compressed", "Books", "Science"])
     torrent_state = metadata_store.TorrentState(infohash=infohash, seeders=10, last_check=last_check)
-    metadata_store.TorrentMetadata(title=generate_title(words_count=4), infohash=infohash, origin_id=parent.id_,
-                                   health=torrent_state, tags=category)
+    metadata_store.TorrentMetadata(title=title or generate_title(words_count=4), infohash=infohash,
+                                   origin_id=parent.id_, health=torrent_state, tags=category)
 
     tag_torrent(infohash, tags_db)
 
@@ -114,7 +114,7 @@ def generate_channel(metadata_store: MetadataStore, tags_db: KnowledgeDatabase,
 
     metadata_store.ChannelNode._my_key = default_eccrypto.generate_key('low')
     chan = metadata_store.ChannelMetadata(
-        title=generate_title(words_count=5), subscribed=subscribed, infohash=random_infohash()
+        title=title or generate_title(words_count=5), subscribed=subscribed, infohash=random_infohash()
     )
 
     # add some collections to the channel
@@ -131,13 +131,15 @@ def generate_test_channels(metadata_store, tags_db) -> None:
         generate_channel(metadata_store, tags_db, subscribed=ind % 2 == 0)
 
     # This one is necessary to test filters, etc
-    generate_channel(metadata_store, tags_db, title="non-random channel name")
+    generate_channel(metadata_store, tags_db, title="nonrandom unsubscribed channel name")
 
     # The same, but subscribed
-    generate_channel(metadata_store, tags_db, title="non-random subscribed channel name", subscribed=True)
+    generate_channel(metadata_store, tags_db, title="nonrandom subscribed channel name", subscribed=True)
 
     # Now generate a couple of personal channels
-    chan1 = metadata_store.ChannelMetadata.create_channel(title="personal channel with non-random name")
+    chan1 = metadata_store.ChannelMetadata.create_channel(title="personal channel with nonrandom name")
+    generate_torrent(metadata_store, tags_db, chan1, title='Some torrent with nonrandom name')
+    generate_torrent(metadata_store, tags_db, chan1, title='Another torrent with nonrandom name')
 
     with open(PNG_FILE, "rb") as f:
         pic_bytes = f.read()

src/tribler/core/utilities/tests/test_utilities.py

@@ -135,9 +135,9 @@ def test_to_fts_query():
     assert to_fts_query(None) is None
     assert to_fts_query('') is None
     assert to_fts_query('   ') is None
-    assert to_fts_query('  abc') == '"abc"*'
-    assert to_fts_query('abc def') == '"abc" "def"*'
-    assert to_fts_query('[abc, def]: xyz?!') == '"abc" "def" "xyz"*'
+    assert to_fts_query('  abc') == '"abc"'
+    assert to_fts_query('abc def') == '"abc" "def"'
+    assert to_fts_query('[abc, def]: xyz?!') == '"abc" "def" "xyz"'
 
 
 def test_extract_tags():

src/tribler/core/utilities/utilities.py

@@ -253,7 +253,7 @@ def to_fts_query(text):
     if not words:
         return None
 
-    return ' '.join(words) + '*'
+    return ' '.join(words)
 
 
 def show_system_popup(title, text):

src/tribler/gui/tests/test_gui.py

@@ -217,17 +217,21 @@ def tst_channels_widget(window, widget, widget_name, sort_column=1, test_filter=
     widget.content_table.sortByColumn(sort_column, 1)
     wait_for_list_populated(widget.content_table)
     screenshot(window, name=f"{widget_name}-sorted")
-    max_items = min(widget.content_table.model().channel_info["total"], 50)
-    assert widget.content_table.verticalHeader().count() <= max_items
+    total = widget.content_table.model().channel_info.get("total")
+    if total is not None:
+        max_items = min(total, 50)
+        assert widget.content_table.verticalHeader().count() <= max_items
 
     # Filter
     if test_filter:
         old_num_items = widget.content_table.verticalHeader().count()
-        QTest.keyClick(widget.channel_torrents_filter_input, 'r')
+        widget.channel_torrents_filter_input.setText("nonrandom")
+        widget.controller.on_filter_input_return_pressed()
         wait_for_list_populated(widget.content_table)
         screenshot(window, name=f"{widget_name}-filtered")
         assert widget.content_table.verticalHeader().count() <= old_num_items
-        QTest.keyPress(widget.channel_torrents_filter_input, Qt.Key_Backspace)
+        widget.channel_torrents_filter_input.setText("")
+        widget.controller.on_filter_input_return_pressed()
         wait_for_list_populated(widget.content_table)
 
     if test_subscribe:
@@ -380,14 +384,14 @@ def test_download_details(window):
 @pytest.mark.guitest
 def test_search_suggestions(window):
     QTest.keyClick(window.top_search_bar, 't')
-    QTest.keyClick(window.top_search_bar, 'r')
+    QTest.keyClick(window.top_search_bar, 'o')
     wait_for_signal(window.received_search_completions)
     screenshot(window, name="search_suggestions")
 
 
 @pytest.mark.guitest
 def test_search(window):
-    window.top_search_bar.setText("a")  # This is likely to trigger some search results
+    window.top_search_bar.setText("torrent")  # This is likely to trigger some search results
     QTest.keyClick(window.top_search_bar, Qt.Key_Enter)
     QTest.qWait(100)
     screenshot(window, name="search_loading_page")

src/tribler/gui/widgets/tablecontentmodel.py

@@ -343,6 +343,14 @@ def perform_query(self, **kwargs):
         txt_filter = to_fts_query(self.text_filter)
         if txt_filter:
             kwargs.update({"txt_filter": txt_filter})
+            # Global full-text search queries should not request the total number of rows for several reasons:
+            # * The total number of rows is useful for paginated queries, and FTS queries in Tribler are not paginated.
+            # * Our goal is to display the most relevant results for the user at the top of the search result list.
+            #   The user doesn't need to see that the database has exactly 300001 results for the "MP3" search.
+            #   In other words, we should search like Google, not Altavista.
+            # * The result list also integrates the results from remote peers that are not from the local database.
+            if 'origin_id' not in kwargs:
+                kwargs.pop("include_total", None)
 
         if self.max_rowid is not None:
             kwargs["max_rowid"] = self.max_rowid

src/tribler/gui/widgets/triblertablecontrollers.py

@@ -40,7 +40,7 @@ def __init__(self, table_view, *args, filter_input=None, **kwargs):
 
         self.filter_input = filter_input
         if self.filter_input:
-            connect(self.filter_input.textChanged, self._on_filter_input_change)
+            connect(self.filter_input.returnPressed, self.on_filter_input_return_pressed)
 
     def set_model(self, model):
         self.model = model
@@ -71,7 +71,7 @@ def _get_sort_parameters(self):
         sort_asc = self.table_view.horizontalHeader().sortIndicatorOrder()
         return sort_by, sort_asc
 
-    def _on_filter_input_change(self, _):
+    def on_filter_input_return_pressed(self):
         self.model.text_filter = self.filter_input.text().lower()
         self.model.reset()