Index: cache.rkt
==================================================================
--- cache.rkt
+++ cache.rkt
@@ -18,10 +18,12 @@
          (schema-out cache:note)
          (schema-out cache:index-entry)
          (schema-out listing)
          delete-article!
          delete-notes!
+         delete-index-entries!
+         save-index-entries!
          articles
          articles+notes
          listing-htmls
          fenced-listing
          unfence)
@@ -99,10 +101,19 @@
   (query-exec (cache-conn)
               (~> (from cache:note #:as n)
                   (where (= n.page ,(format "~a" page)))
                   delete)))
 
+(define (delete-index-entries! page)
+  (query-exec (cache-conn)
+              (~> (from cache:index-entry #:as e)
+                  (where (= e.page ,(format "~a" page)))
+                  delete)))
+
+(define (save-index-entries! es)
+  (void (apply insert! (cache-conn) es)))
+
 ;;
 ;;  ~~~ Fetching articles and notes ~~~
 ;;
 
 ;; (Private use) Conveniece function for the WHERE `series-page` clause

Index: crystalize.rkt
==================================================================
--- crystalize.rkt
+++ crystalize.rkt
@@ -239,18 +239,28 @@
      (make-cache:index-entry
       #:entry main
       #:subentry sub
       #:page pagenode
       #:html-anchor (attr-ref tx 'id))]))
+
+;; Get index entries out of metas
+(define (current-metas-keyword-entries pagenode)
+  (for/list ([kw (in-list (string-split (maybe-meta 'keywords "") #px",\\s*"))])
+    (match (split-entry kw)
+      [(list main sub)
+       (make-cache:index-entry
+        #:entry main
+        #:subentry sub
+        #:page pagenode
+        #:html-anchor "")])))
 
 ;; Save any index entries in doc to the SQLite cache.
 ;; Sub-entries are specified by "!" in the index key
 (define (cache-index-entries! pagenode doc)
   (define-values (_ entry-txs) (splitf-txexpr doc index-entry-txpr?))
-  ; Naive idempotence: delete and re-insert all index entries every time doc is rendered.
-  (query-exec (cache-conn) (delete (~> (from cache:index-entry #:as entry)
-                                       (where (= entry.page ,(symbol->string pagenode))))))
-  (unless (null? entry-txs)
-    (void
-     (apply insert! (cache-conn)
-            (for/list ([etx (in-list entry-txs)])
-              (txexpr->index-entry etx pagenode))))))
+  (define all-entries
+    (append (for/list ([etx (in-list entry-txs)]) (txexpr->index-entry etx pagenode))
+            (current-metas-keyword-entries pagenode)))
+  
+  (delete-index-entries! pagenode)
+  (save-index-entries! all-entries))
+