refactor(migrations): simplify pgmq.meta backfill migration

- Remove verification step as it is not needed
- Add descriptive aliases to improve query readability
- Maintain fully qualified table names in FROM clause
- Remove redundant nested IF EXISTS check

Co-Authored-By: [email protected] <[email protected]>

Author: devin-ai-integration[bot]

migrations/db/migrations/20241215003910_backfill_pgmq_metadata.sql

@@ -1,63 +1,28 @@
 -- migrate:up
 do $$
 begin
-    -- First, verify that pgmq.meta is a regular table with the required structure
+    -- Check if the pgmq.meta table exists
     if exists (
         select 1
-        from pg_catalog.pg_class c
-        join pg_catalog.pg_namespace n on c.relnamespace = n.oid
-        where n.nspname = 'pgmq'
-        and c.relname = 'meta'
-        and c.relkind = 'r'  -- Verify it's a regular table
-        -- Verify the table has exactly these columns and no others
-        and (
-            select count(*)
-            from pg_catalog.pg_attribute a
-            where a.attrelid = c.oid
-            and a.attnum > 0
-            and not a.attisdropped
-        ) = 4  -- Only 4 columns should exist
-        and not exists (
-            select 1
-            from pg_catalog.pg_attribute a
-            where a.attrelid = c.oid
-            and a.attnum > 0
-            and not a.attisdropped
-            and a.attname not in ('queue_name', 'is_partitioned', 'is_unlogged', 'created_at')
-        )  -- No other columns should exist
-        and exists (
-            select 1
-            from pg_catalog.pg_attribute a
-            where a.attrelid = c.oid
-            and a.attnum > 0
-            and not a.attisdropped
-            and a.attname in ('queue_name', 'is_partitioned', 'is_unlogged', 'created_at')
-            having count(*) = 4  -- All required columns must exist
-        )
+        from pg_catalog.pg_class cls
+        join pg_catalog.pg_namespace ns on cls.relnamespace = ns.oid
+        where ns.nspname = 'pgmq' and cls.relname = 'meta'
     ) then
-        -- Check if the pgmq.meta table exists
-        if exists (
-            select 1
-            from pg_catalog.pg_class c
-            join pg_catalog.pg_namespace n on c.relnamespace = n.oid
-            where n.nspname = 'pgmq' and c.relname = 'meta'
-        ) then
-            -- Insert data into pgmq.meta for all tables matching the naming pattern 'pgmq.q_<queue_name>'
-            insert into pgmq.meta (queue_name, is_partitioned, is_unlogged, created_at)
-            select
-                substring(c.relname from 3) as queue_name,
-                false as is_partitioned,
-                case when c.relpersistence = 'u' then true else false end as is_unlogged,
-                now() as created_at
-            from
-                pg_catalog.pg_class c
-                join pg_catalog.pg_namespace n
-                    on c.relnamespace = n.oid
-            where
-                n.nspname = 'pgmq'
-                and c.relname like 'q_%'
-                and c.relkind in ('r', 'p', 'u');
-        end if;
+        -- Insert data into pgmq.meta for all tables matching the naming pattern 'pgmq.q_<queue_name>'
+        insert into pgmq.meta (queue_name, is_partitioned, is_unlogged, created_at)
+        select
+            substring(cls.relname from 3) as queue_name,
+            false as is_partitioned,
+            case when cls.relpersistence = 'u' then true else false end as is_unlogged,
+            now() as created_at
+        from
+            pg_catalog.pg_class cls
+            join pg_catalog.pg_namespace ns
+                on cls.relnamespace = ns.oid
+        where
+            ns.nspname = 'pgmq'
+            and cls.relname like 'q_%'
+            and cls.relkind in ('r', 'p', 'u');
     end if;
 end $$;