Refactor code structure for improved readability and maintainability

sql/diagnotics/monitor-query-performance.sql

@@ -19,51 +19,51 @@ ORDER BY duration DESC;
 -- 2. Show index usage statistics for BaseItems table
 SELECT
     schemaname,
-    reltablename,
-    indexname,
+    relname,
+    indexrelname,
     idx_scan AS index_scans,
     idx_tup_read AS tuples_read,
     idx_tup_fetch AS tuples_fetched,
     pg_size_pretty(pg_relation_size(indexrelid)) AS index_size,
-    CASE 
+    CASE
         WHEN idx_scan = 0 THEN 'UNUSED'
         WHEN idx_scan < 10 THEN 'RARELY USED'
         WHEN idx_scan < 100 THEN 'OCCASIONALLY USED'
         ELSE 'FREQUENTLY USED'
     END AS usage_level
 FROM pg_stat_user_indexes
-WHERE tablename = 'BaseItems'
+WHERE relname = 'BaseItems'
   AND schemaname = 'library'
-ORDER BY idx_scan DESC, indexname;
+ORDER BY idx_scan DESC, indexrelname;
 
 -- 3. Find missing indexes (sequential scans on BaseItems)
 SELECT
     schemaname,
-    reltablename,
+    relname,
     seq_scan AS sequential_scans,
     seq_tup_read AS rows_read_sequentially,
     idx_scan AS index_scans,
     n_tup_ins AS rows_inserted,
     n_tup_upd AS rows_updated,
     n_tup_del AS rows_deleted,
-    CASE 
+    CASE
         WHEN seq_scan > 0 AND idx_scan = 0 THEN 'INDEX NEEDED'
         WHEN seq_scan > idx_scan THEN 'MORE INDEXES MAY HELP'
         ELSE 'INDEXES WORKING WELL'
     END AS recommendation
 FROM pg_stat_user_tables
-WHERE tablename = 'BaseItems'
+WHERE relname = 'BaseItems'
   AND schemaname = 'library';
 
 -- 4. Show table and index sizes
 SELECT
     schemaname,
-    reltablename,
-    pg_size_pretty(pg_total_relation_size(schemaname||'.'||tablename)) AS total_size,
-    pg_size_pretty(pg_relation_size(schemaname||'.'||tablename)) AS table_size,
-    pg_size_pretty(pg_total_relation_size(schemaname||'.'||tablename) - pg_relation_size(schemaname||'.'||tablename)) AS indexes_size
+    relname,
+    pg_size_pretty(pg_total_relation_size(schemaname||'.'||relname)) AS total_size,
+    pg_size_pretty(pg_relation_size(schemaname||'.'||relname)) AS table_size,
+    pg_size_pretty(pg_total_relation_size(schemaname||'.'||relname) - pg_relation_size(schemaname||'.'||relname)) AS indexes_size
 FROM pg_stat_user_tables
-WHERE tablename = 'BaseItems'
+WHERE relname = 'BaseItems'
   AND schemaname = 'library';
 
 -- 5. Show query statistics from pg_stat_statements (if extension is enabled)