fix(candles): serve chart from cache and stabilize any-source

kustomize/base/initdb/001_init.sql

@@ -162,27 +162,52 @@ RETURNS SETOF public.drift_candles
 LANGUAGE sql
 STABLE
 AS $$
-  WITH base AS (
+  WITH src AS (
+    SELECT COALESCE(p_source, '') AS source_key
+  ),
+  cached AS (
+    SELECT
+      c.bucket,
+      c.open,
+      c.high,
+      c.low,
+      c.close,
+      c.oracle_close,
+      c.ticks
+    FROM public.drift_candles_cache c, src
+    WHERE c.symbol = p_symbol
+      AND c.bucket_seconds = p_bucket_seconds
+      AND c.source = src.source_key
+    ORDER BY c.bucket DESC
+    LIMIT p_limit
+  ),
+  fallback AS (
     SELECT
       time_bucket(make_interval(secs => p_bucket_seconds), ts) AS bucket,
       ts,
       COALESCE(mark_price, oracle_price) AS px,
       oracle_price AS oracle_px
-    FROM public.drift_ticks
+    FROM public.drift_ticks, src
     WHERE symbol = p_symbol
-      AND (p_source IS NULL OR source = p_source)
+      AND (src.source_key = '' OR source = src.source_key)
       AND ts >= now() - make_interval(secs => (p_bucket_seconds * p_limit * 2))
+  ),
+  computed AS (
+    SELECT
+      bucket,
+      (array_agg(px ORDER BY ts ASC))[1] AS open,
+      max(px) AS high,
+      min(px) AS low,
+      (array_agg(px ORDER BY ts DESC))[1] AS close,
+      (array_agg(oracle_px ORDER BY ts DESC))[1] AS oracle_close,
+      count(*) AS ticks
+    FROM fallback
+    GROUP BY bucket
   )
-  SELECT
-    bucket,
-    (array_agg(px ORDER BY ts ASC))[1] AS open,
-    max(px) AS high,
-    min(px) AS low,
-    (array_agg(px ORDER BY ts DESC))[1] AS close,
-    (array_agg(oracle_px ORDER BY ts DESC))[1] AS oracle_close,
-    count(*) AS ticks
-  FROM base
-  GROUP BY bucket
+  SELECT * FROM cached
+  UNION ALL
+  SELECT * FROM computed
+  WHERE NOT EXISTS (SELECT 1 FROM cached)
   ORDER BY bucket DESC
   LIMIT p_limit;
 $$;