Add some warnings and notes about slow upgrade (#7275)

Fixes #7144.
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Richard van der Hoff 2020-04-15 12:40:43 +01:00 committed by GitHub
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2 changed files with 74 additions and 2 deletions

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@ -34,12 +34,19 @@ Bugfixes
Synapse 1.12.0 (2020-03-23)
===========================
No significant changes since 1.12.0rc1.
Debian packages and Docker images are rebuilt using the latest versions of
dependency libraries, including Twisted 20.3.0. **Please see security advisory
below**.
Potential slow database update during upgrade
---------------------------------------------
Synapse 1.12.0 includes a database update which is run as part of the upgrade,
and which may take some time (several hours in the case of a large
server). Synapse will not respond to HTTP requests while this update is taking
place. For imformation on seeing if you are affected, and workaround if you
are, see the [upgrade notes](UPGRADE.rst#upgrading-to-v1120).
Security advisory
-----------------

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@ -75,6 +75,71 @@ for example:
wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
Upgrading to v1.12.0
====================
This version includes a database update which is run as part of the upgrade,
and which may take some time (several hours in the case of a large
server). Synapse will not respond to HTTP requests while this update is taking
place.
This is only likely to be a problem in the case of a server which is
participating in many rooms.
0. As with all upgrades, it is recommended that you have a recent backup of
your database which can be used for recovery in the event of any problems.
1. As an initial check to see if you will be affected, you can try running the
following query from the `psql` or `sqlite3` console. It is safe to run it
while Synapse is still running.
.. code:: sql
SELECT MAX(q.v) FROM (
SELECT (
SELECT ej.json AS v
FROM state_events se INNER JOIN event_json ej USING (event_id)
WHERE se.room_id=rooms.room_id AND se.type='m.room.create' AND se.state_key=''
LIMIT 1
) FROM rooms WHERE rooms.room_version IS NULL
) q;
This query will take about the same amount of time as the upgrade process: ie,
if it takes 5 minutes, then it is likely that Synapse will be unresponsive for
5 minutes during the upgrade.
If you consider an outage of this duration to be acceptable, no further
action is necessary and you can simply start Synapse 1.12.0.
If you would prefer to reduce the downtime, continue with the steps below.
2. The easiest workaround for this issue is to manually
create a new index before upgrading. On PostgreSQL, his can be done as follows:
.. code:: sql
CREATE INDEX CONCURRENTLY tmp_upgrade_1_12_0_index
ON state_events(room_id) WHERE type = 'm.room.create';
The above query may take some time, but is also safe to run while Synapse is
running.
We assume that no SQLite users have databases large enough to be
affected. If you *are* affected, you can run a similar query, omitting the
``CONCURRENTLY`` keyword. Note however that this operation may in itself cause
Synapse to stop running for some time. Synapse admins are reminded that
`SQLite is not recommended for use outside a test
environment <https://github.com/matrix-org/synapse/blob/master/README.rst#using-postgresql>`_.
3. Once the index has been created, the ``SELECT`` query in step 1 above should
complete quickly. It is therefore safe to upgrade to Synapse 1.12.0.
4. Once Synapse 1.12.0 has successfully started and is responding to HTTP
requests, the temporary index can be removed:
.. code:: sql
DROP INDEX tmp_upgrade_1_12_0_index;
Upgrading to v1.10.0
====================