Sep 4 - Add link relavant issues function

app/utils/sla.py

@@ -110,11 +110,38 @@ def send_sla_alerts():
 
     logger = logging.getLogger(__name__)
 
-    # yield_per streams rows in batches of 100 rather than loading all open
-    # issues into memory at once.  At current scale this is a no-op difference,
-    # but it prevents a memory spike if the issue count grows large.
+    # Narrow to actual CANDIDATES in SQL rather than reading every open issue
+    # and deciding in Python. This runs every 30 minutes forever, so the old
+    # form's cost grew with the whole open-issue backlog even on a quiet night
+    # where nothing was due. Three filters, each mirroring a `continue` below:
+    #
+    #   1. reported_at IS NOT NULL — the column is nullable, and sla_status()
+    #      raises TypeError on a NULL (datetime + timedelta). One such row
+    #      would abort the entire cron run, so exclude it in SQL.
+    #   2. sla_notified <> 'breached' — the highest level is already sent; the
+    #      loop skips these unconditionally.
+    #   3. old enough to be at least at-risk for its OWN severity, i.e.
+    #      reported_at <= now - (window * 0.75). A critical issue qualifies
+    #      after 3h, a low one after 90h.
+    #
+    # Anything this excludes would have hit a `continue` anyway, so the set of
+    # notifications sent is unchanged — only the rows read are.
+    now = now_eastern()
+    age_clauses = [
+        db.and_(
+            Issue.severity == severity,
+            Issue.reported_at <= now - timedelta(hours=hours * AT_RISK_THRESHOLD),
+        )
+        for severity, hours in SLA_HOURS.items()
+    ]
+
+    # yield_per streams the survivors in batches rather than materialising them
+    # all at once.
     open_issues = Issue.query.filter(
-        Issue.status.in_(['open', 'in_progress', 'pending_verification'])
+        Issue.status.in_(['open', 'in_progress', 'pending_verification']),
+        Issue.reported_at.isnot(None),
+        db.or_(Issue.sla_notified.is_(None), Issue.sla_notified != 'breached'),
+        db.or_(*age_clauses),
     ).yield_per(100)
 
     total_sent = 0