Stop populating events.content
This field is no longer read from, so we should stop populating it. Once we're
happy that this doesn't break everything, and a rollback is unlikely, we can
think about dropping the column.
1 files changed, 93 insertions, 0 deletions
diff --git a/synapse/storage/schema/delta/50/make_event_content_nullable.py b/synapse/storage/schema/delta/50/make_event_content_nullable.py
new file mode 100644
index 0000000000..fa4a289514
--- /dev/null
+++ b/synapse/storage/schema/delta/50/make_event_content_nullable.py
@@ -0,0 +1,93 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector 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.
+
+"""
+We want to stop populating 'event.content', so we need to make it nullable.
+
+If this has to be rolled back, then the following should populate the missing data:
+
+Postgres:
+
+ UPDATE events SET content=(ej.json::json)->'content' FROM event_json ej
+ WHERE ej.event_id = events.event_id AND
+ stream_ordering < (
+ SELECT stream_ordering FROM events WHERE content IS NOT NULL
+ ORDER BY stream_ordering LIMIT 1
+ );
+
+ UPDATE events SET content=(ej.json::json)->'content' FROM event_json ej
+ WHERE ej.event_id = events.event_id AND
+ stream_ordering > (
+ SELECT stream_ordering FROM events WHERE content IS NOT NULL
+ ORDER BY stream_ordering DESC LIMIT 1
+ );
+
+SQLite:
+
+ UPDATE events SET content=(
+ SELECT json_extract(json,'$.content') FROM event_json ej
+ WHERE ej.event_id = events.event_id
+ )
+ WHERE
+ stream_ordering < (
+ SELECT stream_ordering FROM events WHERE content IS NOT NULL
+ ORDER BY stream_ordering LIMIT 1
+ )
+ OR stream_ordering > (
+ SELECT stream_ordering FROM events WHERE content IS NOT NULL
+ ORDER BY stream_ordering DESC LIMIT 1
+ );
+
+"""
+
+import logging
+
+from synapse.storage.engines import PostgresEngine
+
+logger = logging.getLogger(__name__)
+
+
+def run_create(cur, database_engine, *args, **kwargs):
+ if isinstance(database_engine, PostgresEngine):
+ cur.execute("""
+ ALTER TABLE events ALTER COLUMN content DROP NOT NULL;
+ """)
+ return
+
+ # sqlite is an arse about this. ref: https://www.sqlite.org/lang_altertable.html
+ cur.execute("PRAGMA schema_version")
+ (oldver,) = cur.fetchone()
+
+ cur.execute("SELECT sql FROM sqlite_master WHERE tbl_name='events' AND type='table'")
+ (oldsql,) = cur.fetchone()
+ sql = oldsql.replace("content TEXT NOT NULL", "content TEXT")
+ if sql == oldsql:
+ raise Exception("Couldn't find null constraint to drop in %s" % oldsql)
+
+ logger.info("Replacing definition of 'events' with: %s", sql)
+
+ cur.execute("PRAGMA writable_schema=ON")
+
+ cur.execute(
+ "UPDATE sqlite_master SET sql=? WHERE tbl_name='events' AND type='table'",
+ (sql, ),
+ )
+
+ cur.execute("PRAGMA schema_version=%i" % (oldver+1,))
+ cur.execute("PRAGMA writable_schema=OFF")
+
+
+def run_upgrade(*args, **kwargs):
+ pass
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