Add a worker store for search insertion. (matrix-org#7516)

This is required as both event persistence and the background update needs access to this function. It should be perfectly safe for two workers to write to that table at the same time.

changelog.d/7516.misc

@@ -0,0 +1 @@
+Add a worker store for search insertion, required for moving event persistence off master.

synapse/app/generic_worker.py

@@ -122,6 +122,7 @@
     MonthlyActiveUsersWorkerStore,
 )
 from synapse.storage.data_stores.main.presence import UserPresenceState
+from synapse.storage.data_stores.main.search import SearchWorkerStore
 from synapse.storage.data_stores.main.ui_auth import UIAuthWorkerStore
 from synapse.storage.data_stores.main.user_directory import UserDirectoryStore
 from synapse.types import ReadReceipt
@@ -451,6 +452,7 @@ class GenericWorkerSlavedStore(
     SlavedFilteringStore,
     MonthlyActiveUsersWorkerStore,
     MediaRepositoryStore,
+    SearchWorkerStore,
     BaseSlavedStore,
 ):
     def __init__(self, database, db_conn, hs):

synapse/storage/data_stores/main/search.py

@@ -37,7 +37,55 @@
 )
 
 
-class SearchBackgroundUpdateStore(SQLBaseStore):
+class SearchWorkerStore(SQLBaseStore):
+    def store_search_entries_txn(self, txn, entries):
+        """Add entries to the search table
+
+        Args:
+            txn (cursor):
+            entries (iterable[SearchEntry]):
+                entries to be added to the table
+        """
+        if not self.hs.config.enable_search:
+            return
+        if isinstance(self.database_engine, PostgresEngine):
+            sql = (
+                "INSERT INTO event_search"
+                " (event_id, room_id, key, vector, stream_ordering, origin_server_ts)"
+                " VALUES (?,?,?,to_tsvector('english', ?),?,?)"
+            )
+
+            args = (
+                (
+                    entry.event_id,
+                    entry.room_id,
+                    entry.key,
+                    entry.value,
+                    entry.stream_ordering,
+                    entry.origin_server_ts,
+                )
+                for entry in entries
+            )
+
+            txn.executemany(sql, args)
+
+        elif isinstance(self.database_engine, Sqlite3Engine):
+            sql = (
+                "INSERT INTO event_search (event_id, room_id, key, value)"
+                " VALUES (?,?,?,?)"
+            )
+            args = (
+                (entry.event_id, entry.room_id, entry.key, entry.value)
+                for entry in entries
+            )
+
+            txn.executemany(sql, args)
+        else:
+            # This should be unreachable.
+            raise Exception("Unrecognized database engine")
+
+
+class SearchBackgroundUpdateStore(SearchWorkerStore):
 
     EVENT_SEARCH_UPDATE_NAME = "event_search"
     EVENT_SEARCH_ORDER_UPDATE_NAME = "event_search_order"
@@ -296,52 +344,6 @@ def reindex_search_txn(txn):
 
         return num_rows
 
-    def store_search_entries_txn(self, txn, entries):
-        """Add entries to the search table
-
-        Args:
-            txn (cursor):
-            entries (iterable[SearchEntry]):
-                entries to be added to the table
-        """
-        if not self.hs.config.enable_search:
-            return
-        if isinstance(self.database_engine, PostgresEngine):
-            sql = (
-                "INSERT INTO event_search"
-                " (event_id, room_id, key, vector, stream_ordering, origin_server_ts)"
-                " VALUES (?,?,?,to_tsvector('english', ?),?,?)"
-            )
-
-            args = (
-                (
-                    entry.event_id,
-                    entry.room_id,
-                    entry.key,
-                    entry.value,
-                    entry.stream_ordering,
-                    entry.origin_server_ts,
-                )
-                for entry in entries
-            )
-
-            txn.executemany(sql, args)
-
-        elif isinstance(self.database_engine, Sqlite3Engine):
-            sql = (
-                "INSERT INTO event_search (event_id, room_id, key, value)"
-                " VALUES (?,?,?,?)"
-            )
-            args = (
-                (entry.event_id, entry.room_id, entry.key, entry.value)
-                for entry in entries
-            )
-
-            txn.executemany(sql, args)
-        else:
-            # This should be unreachable.
-            raise Exception("Unrecognized database engine")
-
 
 class SearchStore(SearchBackgroundUpdateStore):
     def __init__(self, database: Database, db_conn, hs):