WIP

backend/resources/migrations/postgres/20260709000000_freeze_config.down.sql

@@ -0,0 +1,16 @@
+-- Recreate the standalone config table with the same schema it had before it was frozen
+CREATE TABLE app_config_variables
+(
+    key   VARCHAR(100) NOT NULL PRIMARY KEY,
+    value TEXT NOT NULL
+);
+
+-- Populate it from the frozen JSON document stored in the "kv" table
+-- json_each expands the JSON object back into one row per key/value pair.
+INSERT INTO app_config_variables (key, value)
+SELECT je.key, je.value
+FROM kv, json_each_text(kv."value"::json) AS je(key, value)
+WHERE kv."key" = 'config_migrated';
+
+-- Remove the frozen config from the "kv" table
+DELETE FROM kv WHERE "key" = 'config_migrated';

backend/resources/migrations/postgres/20260709000000_freeze_config.up.sql

@@ -0,0 +1,12 @@
+-- Freeze the app configuration
+-- Encode every row of the standalone config table as a single JSON object (mapping key -> value) and store it in the "kv" table under the "config_migrated" key
+--
+-- json_object_agg aggregates all rows into a JSON object
+-- The "HAVING count(*) > 0" clause ensures that nothing is written to the "kv" table when the config table is empty
+INSERT INTO kv ("key", "value")
+SELECT 'config_migrated', json_object_agg("key", "value")::text
+FROM app_config_variables
+HAVING count(*) > 0;
+
+-- Drop the now-frozen standalone config table
+DROP TABLE app_config_variables;