diff --git a/collects/db/private/sqlite3/connection.rkt b/collects/db/private/sqlite3/connection.rkt
index 3d9a4b5657..c181dd5d3b 100644
--- a/collects/db/private/sqlite3/connection.rkt
+++ b/collects/db/private/sqlite3/connection.rkt
@@ -135,13 +135,13 @@
       (let*-values ([(db) (get-db fsym)]
                     [(prep-status stmt)
                      (HANDLE fsym
-                      (let-values ([(prep-status stmt tail)
+                      (let-values ([(prep-status stmt tail?)
                                     (sqlite3_prepare_v2 db sql)])
                         (define (free!) (when stmt (sqlite3_finalize stmt)))
-                        (when (string=? sql tail)
-                          (free!) (uerror fsym "SQL syntax error in ~e" tail))
-                        (when (not (zero? (string-length tail)))
-                          (free!) (uerror fsym "multiple SQL statements given: ~e" tail))
+                        (unless stmt
+                          (uerror fsym "SQL syntax error in ~e" sql))
+                        (when tail?
+                          (free!) (uerror fsym "multiple SQL statements given: ~e" sql))
                         (values prep-status stmt)))])
         (unless stmt (error/internal fsym "prepare failed"))
         (let* ([param-typeids
diff --git a/collects/db/private/sqlite3/ffi.rkt b/collects/db/private/sqlite3/ffi.rkt
index 8fd7e8ce78..af7260cfbb 100644
--- a/collects/db/private/sqlite3/ffi.rkt
+++ b/collects/db/private/sqlite3/ffi.rkt
@@ -36,13 +36,25 @@
 
 ;; -- Stmt --
 
+(define (copy-buffer buffer)
+  (let* ([buffer (string->bytes/utf-8 buffer)]
+         [n (bytes-length buffer)]
+         [rawcopy (malloc (add1 n) 'atomic-interior)]
+         [copy (make-sized-byte-string rawcopy n)])
+    (memcpy copy buffer n)
+    (ptr-set! rawcopy _byte n 0)
+    copy))
+
 (define-sqlite sqlite3_prepare_v2
-  (_fun (db zsql) ::
-        (db : _sqlite3_database) (zsql : _string) ((string-utf-8-length zsql) : _int)
+  (_fun (db sql) ::
+        (db : _sqlite3_database)
+        (sql-buffer : _bytes = (copy-buffer sql))
+        ((bytes-length sql-buffer) : _int)
         ;; bad prepare statements set statement to NULL, with no error reported
-        (statement : (_ptr o _sqlite3_statement/null)) (tail : (_ptr o _string))
+        (statement : (_ptr o _sqlite3_statement/null))
+        (tail : (_ptr o _bytes)) ;; points into sql-buffer (atomic-interior)
         -> (result : _int)
-        -> (values result statement tail)))
+        -> (values result statement (and tail (positive? (bytes-length tail))))))
 
 (define-sqlite sqlite3_finalize
   (_fun _sqlite3_statement