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Add SIGHUP deprecation notice

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steve-chavez
2018-09-20 10:47:52 -05:00
committed by Steve Chávez
parent 7052446abf
commit efb39e5e12
2 changed files with 10 additions and 5 deletions
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admin.rst
+9 -5
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@@ -187,11 +187,11 @@ Schema Reloading
Users are often confused by PostgREST's database schema cache. It is present because detecting foreign key relationships between tables (including how those relationships pass through views) is necessary, but costly. API requests consult the schema cache as part of :ref:`resource_embedding`. However if the schema changes while the server is running it results in a stale cache and leads to errors claiming that no relations are detected between tables. Users are often confused by PostgREST's database schema cache. It is present because detecting foreign key relationships between tables (including how those relationships pass through views) is necessary, but costly. API requests consult the schema cache as part of :ref:`resource_embedding`. However if the schema changes while the server is running it results in a stale cache and leads to errors claiming that no relations are detected between tables.
To refresh the cache without restarting the PostgREST server, send the server process a SIGHUP signal: To refresh the cache without restarting the PostgREST server, send the server process a SIGUSR1 signal:
.. code:: bash .. code:: bash
killall -HUP postgrest killall -SIGUSR1 postgrest
The above is the manual way to do it. To automate the schema reloads, use a database trigger like this: The above is the manual way to do it. To automate the schema reloads, use a database trigger like this:
@@ -209,14 +209,18 @@ The above is the manual way to do it. To automate the schema reloads, use a data
CREATE EVENT TRIGGER ddl_postgrest ON ddl_command_end CREATE EVENT TRIGGER ddl_postgrest ON ddl_command_end
EXECUTE PROCEDURE public.notify_ddl_postgrest(); EXECUTE PROCEDURE public.notify_ddl_postgrest();
Then run the `pg_listen <https://github.com/begriffs/pg_listen>`_ utility to monitor for that event and send a SIGHUP when it occurs: Then run the `pg_listen <https://github.com/begriffs/pg_listen>`_ utility to monitor for that event and send a SIGUSR1 when it occurs:
.. code-block:: bash .. code-block:: bash
pg_listen <db-uri> ddl_command_end "killall -HUP postgrest" pg_listen <db-uri> ddl_command_end "killall -SIGUSR1 postgrest"
Now, whenever the structure of the database schema changes, PostgreSQL will notify the ``ddl_command_end`` channel, which will cause ``pg_listen`` to send PostgREST the signal to reload its cache. Now, whenever the structure of the database schema changes, PostgreSQL will notify the ``ddl_command_end`` channel, which will cause ``pg_listen`` to send PostgREST the signal to reload its cache.
.. important::
As of PostgREST v5.1 reloading with SIGHUP is deprecated, it's still supported but will be removed in v6.0
Daemonizing Daemonizing
=========== ===========
@@ -246,7 +250,7 @@ Then create the systemd service file in ``/etc/systemd/system/postgrest.service`
[Service] [Service]
ExecStart=/bin/postgrest /etc/postgrest/config ExecStart=/bin/postgrest /etc/postgrest/config
ExecReload=/bin/kill -HUP $MAINPID ExecReload=/bin/kill -SIGUSR1 $MAINPID
[Install] [Install]
WantedBy=multi-user.target WantedBy=multi-user.target
postgrest.dict
+1
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@@ -46,6 +46,7 @@ RabbitMQ
RestSharp RestSharp
SHA SHA
SIGHUP SIGHUP
SIGUSR1
SNS SNS
SQL SQL
SSL SSL