Merge pull request #359 from matrix-org/markjh/incremental_indexing

Incremental background updates for db indexes

6 files changed, 413 insertions, 77 deletions

diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index a77535a4ee..cd7a52ec07 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -439,6 +439,7 @@ def setup(config_options):
     hs.get_pusherpool().start()
     hs.get_state_handler().start_caching()
     hs.get_datastore().start_profiling()
+    hs.get_datastore().start_doing_background_updates()
     hs.get_replication_layer().start_get_pdu_cache()
 
     return hs
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
new file mode 100644
index 0000000000..45fccc2e5e
--- /dev/null
+++ b/synapse/storage/background_updates.py
@@ -0,0 +1,256 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014, 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import SQLBaseStore
+
+from twisted.internet import defer
+
+import ujson as json
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class BackgroundUpdatePerformance(object):
+    """Tracks the how long a background update is taking to update its items"""
+
+    def __init__(self, name):
+        self.name = name
+        self.total_item_count = 0
+        self.total_duration_ms = 0
+        self.avg_item_count = 0
+        self.avg_duration_ms = 0
+
+    def update(self, item_count, duration_ms):
+        """Update the stats after doing an update"""
+        self.total_item_count += item_count
+        self.total_duration_ms += duration_ms
+
+        # Exponential moving averages for the number of items updated and
+        # the duration.
+        self.avg_item_count += 0.1 * (item_count - self.avg_item_count)
+        self.avg_duration_ms += 0.1 * (duration_ms - self.avg_duration_ms)
+
+    def average_items_per_ms(self):
+        """An estimate of how long it takes to do a single update.
+        Returns:
+            A duration in ms as a float
+        """
+        if self.total_item_count == 0:
+            return None
+        else:
+            # Use the exponential moving average so that we can adapt to
+            # changes in how long the update process takes.
+            return float(self.avg_item_count) / float(self.avg_duration_ms)
+
+    def total_items_per_ms(self):
+        """An estimate of how long it takes to do a single update.
+        Returns:
+            A duration in ms as a float
+        """
+        if self.total_item_count == 0:
+            return None
+        else:
+            return float(self.total_item_count) / float(self.total_duration_ms)
+
+
+class BackgroundUpdateStore(SQLBaseStore):
+    """ Background updates are updates to the database that run in the
+    background. Each update processes a batch of data at once. We attempt to
+    limit the impact of each update by monitoring how long each batch takes to
+    process and autotuning the batch size.
+    """
+
+    MINIMUM_BACKGROUND_BATCH_SIZE = 100
+    DEFAULT_BACKGROUND_BATCH_SIZE = 100
+    BACKGROUND_UPDATE_INTERVAL_MS = 1000
+    BACKGROUND_UPDATE_DURATION_MS = 100
+
+    def __init__(self, hs):
+        super(BackgroundUpdateStore, self).__init__(hs)
+        self._background_update_performance = {}
+        self._background_update_queue = []
+        self._background_update_handlers = {}
+        self._background_update_timer = None
+
+    @defer.inlineCallbacks
+    def start_doing_background_updates(self):
+        while True:
+            if self._background_update_timer is not None:
+                return
+
+            sleep = defer.Deferred()
+            self._background_update_timer = self._clock.call_later(
+                self.BACKGROUND_UPDATE_INTERVAL_MS / 1000., sleep.callback, None
+            )
+            try:
+                yield sleep
+            finally:
+                self._background_update_timer = None
+
+            try:
+                result = yield self.do_background_update(
+                    self.BACKGROUND_UPDATE_DURATION_MS
+                )
+            except:
+                logger.exception("Error doing update")
+
+            if result is None:
+                logger.info(
+                    "No more background updates to do."
+                    " Unscheduling background update task."
+                )
+                return
+
+    @defer.inlineCallbacks
+    def do_background_update(self, desired_duration_ms):
+        """Does some amount of work on a background update
+        Args:
+            desired_duration_ms(float): How long we want to spend
+                updating.
+        Returns:
+            A deferred that completes once some amount of work is done.
+            The deferred will have a value of None if there is currently
+            no more work to do.
+        """
+        if not self._background_update_queue:
+            updates = yield self._simple_select_list(
+                "background_updates",
+                keyvalues=None,
+                retcols=("update_name",),
+            )
+            for update in updates:
+                self._background_update_queue.append(update['update_name'])
+
+        if not self._background_update_queue:
+            defer.returnValue(None)
+
+        update_name = self._background_update_queue.pop(0)
+        self._background_update_queue.append(update_name)
+
+        update_handler = self._background_update_handlers[update_name]
+
+        performance = self._background_update_performance.get(update_name)
+
+        if performance is None:
+            performance = BackgroundUpdatePerformance(update_name)
+            self._background_update_performance[update_name] = performance
+
+        items_per_ms = performance.average_items_per_ms()
+
+        if items_per_ms is not None:
+            batch_size = int(desired_duration_ms * items_per_ms)
+            # Clamp the batch size so that we always make progress
+            batch_size = max(batch_size, self.MINIMUM_BACKGROUND_BATCH_SIZE)
+        else:
+            batch_size = self.DEFAULT_BACKGROUND_BATCH_SIZE
+
+        progress_json = yield self._simple_select_one_onecol(
+            "background_updates",
+            keyvalues={"update_name": update_name},
+            retcol="progress_json"
+        )
+
+        progress = json.loads(progress_json)
+
+        time_start = self._clock.time_msec()
+        items_updated = yield update_handler(progress, batch_size)
+        time_stop = self._clock.time_msec()
+
+        duration_ms = time_stop - time_start
+
+        logger.info(
+            "Updating %r. Updated %r items in %rms."
+            " (total_rate=%r/ms, current_rate=%r/ms, total_updated=%r)",
+            update_name, items_updated, duration_ms,
+            performance.total_items_per_ms(),
+            performance.average_items_per_ms(),
+            performance.total_item_count,
+        )
+
+        performance.update(items_updated, duration_ms)
+
+        defer.returnValue(len(self._background_update_performance))
+
+    def register_background_update_handler(self, update_name, update_handler):
+        """Register a handler for doing a background update.
+
+        The handler should take two arguments:
+
+        * A dict of the current progress
+        * An integer count of the number of items to update in this batch.
+
+        The handler should return a deferred integer count of items updated.
+        The hander is responsible for updating the progress of the update.
+
+        Args:
+            update_name(str): The name of the update that this code handles.
+            update_handler(function): The function that does the update.
+        """
+        self._background_update_handlers[update_name] = update_handler
+
+    def start_background_update(self, update_name, progress):
+        """Starts a background update running.
+
+        Args:
+            update_name: The update to set running.
+            progress: The initial state of the progress of the update.
+
+        Returns:
+            A deferred that completes once the task has been added to the
+            queue.
+        """
+        # Clear the background update queue so that we will pick up the new
+        # task on the next iteration of do_background_update.
+        self._background_update_queue = []
+        progress_json = json.dumps(progress)
+
+        return self._simple_insert(
+            "background_updates",
+            {"update_name": update_name, "progress_json": progress_json}
+        )
+
+    def _end_background_update(self, update_name):
+        """Removes a completed background update task from the queue.
+
+        Args:
+            update_name(str): The name of the completed task to remove
+        Returns:
+            A deferred that completes once the task is removed.
+        """
+        self._background_update_queue = [
+            name for name in self._background_update_queue if name != update_name
+        ]
+        return self._simple_delete_one(
+            "background_updates", keyvalues={"update_name": update_name}
+        )
+
+    def _background_update_progress_txn(self, txn, update_name, progress):
+        """Update the progress of a background update
+
+        Args:
+            txn(cursor): The transaction.
+            update_name(str): The name of the background update task
+            progress(dict): The progress of the update.
+        """
+
+        progress_json = json.dumps(progress)
+
+        self._simple_update_one_txn(
+            txn,
+            "background_updates",
+            keyvalues={"update_name": update_name},
+            updatevalues={"progress_json": progress_json},
+        )
diff --git a/synapse/storage/schema/delta/25/00background_updates.sql b/synapse/storage/schema/delta/25/00background_updates.sql
new file mode 100644
index 0000000000..41a9b59b1b
--- /dev/null
+++ b/synapse/storage/schema/delta/25/00background_updates.sql
@@ -0,0 +1,21 @@
+/* Copyright 2015 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+CREATE TABLE IF NOT EXISTS background_updates(
+    update_name TEXT NOT NULL, -- The name of the background update.
+    progress_json TEXT NOT NULL, -- The current progress of the update as JSON.
+    CONSTRAINT background_updates_uniqueness UNIQUE (update_name)
+);
diff --git a/synapse/storage/schema/delta/25/fts.py b/synapse/storage/schema/delta/25/fts.py
index b7cd0ce3b8..5239d69073 100644
--- a/synapse/storage/schema/delta/25/fts.py
+++ b/synapse/storage/schema/delta/25/fts.py
@@ -22,7 +22,7 @@ import ujson
 logger = logging.getLogger(__name__)
 
 
-POSTGRES_SQL = """
+POSTGRES_TABLE = """
 CREATE TABLE IF NOT EXISTS event_search (
     event_id TEXT,
     room_id TEXT,
@@ -31,22 +31,6 @@ CREATE TABLE IF NOT EXISTS event_search (
     vector tsvector
 );
 
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.body',
-    to_tsvector('english', json::json->'content'->>'body')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.message';
-
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.name',
-    to_tsvector('english', json::json->'content'->>'name')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.name';
-
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.topic',
-    to_tsvector('english', json::json->'content'->>'topic')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.topic';
-
-
 CREATE INDEX event_search_fts_idx ON event_search USING gin(vector);
 CREATE INDEX event_search_ev_idx ON event_search(event_id);
 CREATE INDEX event_search_ev_ridx ON event_search(room_id);
@@ -61,67 +45,34 @@ SQLITE_TABLE = (
 
 def run_upgrade(cur, database_engine, *args, **kwargs):
     if isinstance(database_engine, PostgresEngine):
-        run_postgres_upgrade(cur)
-        return
+        for statement in get_statements(POSTGRES_TABLE.splitlines()):
+            cur.execute(statement)
+    elif isinstance(database_engine, Sqlite3Engine):
+        cur.execute(SQLITE_TABLE)
+    else:
+        raise Exception("Unrecognized database engine")
 
-    if isinstance(database_engine, Sqlite3Engine):
-        run_sqlite_upgrade(cur)
-        return
+    cur.execute("SELECT MIN(stream_ordering) FROM events")
+    rows = cur.fetchall()
+    min_stream_id = rows[0][0]
 
+    cur.execute("SELECT MAX(stream_ordering) FROM events")
+    rows = cur.fetchall()
+    max_stream_id = rows[0][0]
 
-def run_postgres_upgrade(cur):
-    for statement in get_statements(POSTGRES_SQL.splitlines()):
-        cur.execute(statement)
+    if min_stream_id is not None and max_stream_id is not None:
+        progress = {
+            "target_min_stream_id_inclusive": min_stream_id,
+            "max_stream_id_exclusive": max_stream_id + 1,
+            "rows_inserted": 0,
+        }
+        progress_json = ujson.dumps(progress)
 
+        sql = (
+            "INSERT into background_updates (update_name, progress_json)"
+            " VALUES (?, ?)"
+        )
 
-def run_sqlite_upgrade(cur):
-        cur.execute(SQLITE_TABLE)
+        sql = database_engine.convert_param_style(sql)
 
-        rowid = -1
-        while True:
-            cur.execute(
-                "SELECT rowid, json FROM event_json"
-                " WHERE rowid > ?"
-                " ORDER BY rowid ASC LIMIT 100",
-                (rowid,)
-            )
-
-            res = cur.fetchall()
-
-            if not res:
-                break
-
-            events = [
-                ujson.loads(js)
-                for _, js in res
-            ]
-
-            rowid = max(rid for rid, _ in res)
-
-            rows = []
-            for ev in events:
-                content = ev.get("content", {})
-                body = content.get("body", None)
-                name = content.get("name", None)
-                topic = content.get("topic", None)
-                sender = ev.get("sender", None)
-                if ev["type"] == "m.room.message" and body:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.body", body
-                    ))
-                if ev["type"] == "m.room.name" and name:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.name", name
-                    ))
-                if ev["type"] == "m.room.topic" and topic:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.topic", topic
-                    ))
-
-            if rows:
-                logger.info(rows)
-                cur.executemany(
-                    "INSERT INTO event_search (event_id, room_id, sender, key, value)"
-                    " VALUES (?,?,?,?,?)",
-                    rows
-                )
+        cur.execute(sql, ("event_search", progress_json))
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 91a96d2a83..2e88c51ad0 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -15,7 +15,7 @@
 
 from twisted.internet import defer
 
-from _base import SQLBaseStore
+from .background_updates import BackgroundUpdateStore
 from synapse.api.errors import SynapseError
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 
@@ -25,7 +25,106 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-class SearchStore(SQLBaseStore):
+class SearchStore(BackgroundUpdateStore):
+
+    EVENT_SEARCH_UPDATE_NAME = "event_search"
+
+    def __init__(self, hs):
+        super(SearchStore, self).__init__(hs)
+        self.register_background_update_handler(
+            self.EVENT_SEARCH_UPDATE_NAME, self._background_reindex_search
+        )
+
+    @defer.inlineCallbacks
+    def _background_reindex_search(self, progress, batch_size):
+        target_min_stream_id = progress["target_min_stream_id_inclusive"]
+        max_stream_id = progress["max_stream_id_exclusive"]
+        rows_inserted = progress.get("rows_inserted", 0)
+
+        INSERT_CLUMP_SIZE = 1000
+        TYPES = ["m.room.name", "m.room.message", "m.room.topic"]
+
+        def reindex_search_txn(txn):
+            sql = (
+                "SELECT stream_ordering, event_id FROM events"
+                " WHERE ? <= stream_ordering AND stream_ordering < ?"
+                " AND (%s)"
+                " ORDER BY stream_ordering DESC"
+                " LIMIT ?"
+            ) % (" OR ".join("type = '%s'" % (t,) for t in TYPES),)
+
+            txn.execute(sql, (target_min_stream_id, max_stream_id, batch_size))
+
+            rows = txn.fetchall()
+            if not rows:
+                return 0
+
+            min_stream_id = rows[-1][0]
+            event_ids = [row[1] for row in rows]
+
+            events = self._get_events_txn(txn, event_ids)
+
+            event_search_rows = []
+            for event in events:
+                try:
+                    event_id = event.event_id
+                    room_id = event.room_id
+                    content = event.content
+                    if event.type == "m.room.message":
+                        key = "content.body"
+                        value = content["body"]
+                    elif event.type == "m.room.topic":
+                        key = "content.topic"
+                        value = content["topic"]
+                    elif event.type == "m.room.name":
+                        key = "content.name"
+                        value = content["name"]
+                except (KeyError, AttributeError):
+                    # If the event is missing a necessary field then
+                    # skip over it.
+                    continue
+
+                event_search_rows.append((event_id, room_id, key, value))
+
+            if isinstance(self.database_engine, PostgresEngine):
+                sql = (
+                    "INSERT INTO event_search (event_id, room_id, key, vector)"
+                    " VALUES (?,?,?,to_tsvector('english', ?))"
+                )
+            elif isinstance(self.database_engine, Sqlite3Engine):
+                sql = (
+                    "INSERT INTO event_search (event_id, room_id, key, value)"
+                    " VALUES (?,?,?,?)"
+                )
+            else:
+                # This should be unreachable.
+                raise Exception("Unrecognized database engine")
+
+            for index in range(0, len(event_search_rows), INSERT_CLUMP_SIZE):
+                clump = event_search_rows[index:index + INSERT_CLUMP_SIZE]
+                txn.executemany(sql, clump)
+
+            progress = {
+                "target_min_stream_id_inclusive": target_min_stream_id,
+                "max_stream_id_exclusive": min_stream_id,
+                "rows_inserted": rows_inserted + len(event_search_rows)
+            }
+
+            self._background_update_progress_txn(
+                txn, self.EVENT_SEARCH_UPDATE_NAME, progress
+            )
+
+            return len(event_search_rows)
+
+        result = yield self.runInteraction(
+            self.EVENT_SEARCH_UPDATE_NAME, reindex_search_txn
+        )
+
+        if not result:
+            yield self._end_background_update(self.EVENT_SEARCH_UPDATE_NAME)
+
+        defer.returnValue(result)
+
     @defer.inlineCallbacks
     def search_msgs(self, room_ids, search_term, keys):
         """Performs a full text search over events with given keys.
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 1d123ccefc..d69c7cb991 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -53,6 +53,14 @@ class Clock(object):
         loop.stop()
 
     def call_later(self, delay, callback, *args, **kwargs):
+        """Call something later
+
+        Args:
+            delay(float): How long to wait in seconds.
+            callback(function): Function to call
+            *args: Postional arguments to pass to function.
+            **kwargs: Key arguments to pass to function.
+        """
         current_context = LoggingContext.current_context()
 
         def wrapped_callback(*args, **kwargs):