relay: skip TTL deadline bump for known-permanent channels (T1a write-amp) (#2125)

Signed-off-by: Tyler Longwell <tlongwell@block.xyz>
Signed-off-by: npub12gtutshhh76rx0jx697f32f9tffd4hhp3hx58fp4x6u4uemkm7sqf8f757 <5217c5c2f7bfb4333e46d17c98a9255a52dadee18dcd43a43536b95e6776dfa0@sprout-oss.stage.blox.sqprod.co>
Co-authored-by: npub1qyvc0c5kl4gqv2fd97fsk46tu378sqgy35vc83rvgfwne90sel7s0ed67d <011987e296fd5006292d2f930b574be47c7801048d1983c46c425d3c95f0cffd@sprout-oss.stage.blox.sqprod.co>
Co-authored-by: Tyler Longwell <tlongwell@block.xyz>
Co-authored-by: npub12gtutshhh76rx0jx697f32f9tffd4hhp3hx58fp4x6u4uemkm7sqf8f757 <5217c5c2f7bfb4333e46d17c98a9255a52dadee18dcd43a43536b95e6776dfa0@sprout-oss.stage.blox.sqprod.co>

migrations/0022_event_ttl_refresh.sql

@@ -0,0 +1,40 @@
+-- Refresh ephemeral-channel expiry in the transaction that makes a
+-- channel-scoped event durable. Deferring to COMMIT closes the stale-prefetch
+-- race: the UPDATE sees a TTL transition committed while ingest was in flight,
+-- or waits on its row lock and rechecks after it commits, without restoring a
+-- separate hot-path transaction.
+CREATE FUNCTION refresh_channel_ttl_after_event_insert() RETURNS trigger
+LANGUAGE plpgsql AS $$
+BEGIN
+    -- Kind 9007 creates the channel and initializes its deadline itself.
+    IF NEW.channel_id IS NOT NULL AND NEW.kind <> 9007 THEN
+        BEGIN
+            -- Lock by identity before testing ttl_seconds. If a concurrent TTL
+            -- transition is uncommitted, this waits and follows its updated row
+            -- version instead of treating the old permanent version as final.
+            PERFORM 1 FROM channels
+            WHERE community_id = NEW.community_id AND id = NEW.channel_id
+            FOR UPDATE;
+
+            UPDATE channels
+            SET ttl_deadline = clock_timestamp() + make_interval(secs => ttl_seconds)
+            WHERE community_id = NEW.community_id
+              AND id = NEW.channel_id
+              AND ttl_seconds IS NOT NULL
+              AND archived_at IS NULL
+              AND deleted_at IS NULL;
+        EXCEPTION WHEN OTHERS THEN
+            -- Preserve the existing best-effort contract: a TTL refresh failure
+            -- must not reject an otherwise valid durable event.
+            RAISE WARNING 'channel TTL refresh failed for community %, channel %: %',
+                NEW.community_id, NEW.channel_id, SQLERRM;
+        END;
+    END IF;
+    RETURN NULL;
+END
+$$;
+
+CREATE CONSTRAINT TRIGGER events_refresh_channel_ttl
+AFTER INSERT ON events
+DEFERRABLE INITIALLY DEFERRED
+FOR EACH ROW EXECUTE FUNCTION refresh_channel_ttl_after_event_insert();