diff --git a/collects/db/private/generic/common.rkt b/collects/db/private/generic/common.rkt
index 02e575cb63..b1f8d0a583 100644
--- a/collects/db/private/generic/common.rkt
+++ b/collects/db/private/generic/common.rkt
@@ -167,23 +167,28 @@
 
 (define transactions%
   (class locking%
-    (inherit call-with-lock)
-
     #|
     A transaction created via SQL is "unmanaged".
     A transaction created via start-tx, call-with-tx is "managed".
 
-    FIXME: eliminate distinction, if possible.
-      - currently: tx-stack != null means tx-status != #f
-      - would also like: tx-stack = null iff tx-status = #f
+    tx-status : #f, #t, 'invalid
+    Indicates whether in a transaction (managed or unmanaged) and if
+    transaction is valid or invalid.
+
+    tx-stack : (list (cons string boolean) ... (cons #f boolean))
+    Represents the "managed" transaction stack.
+
+    If tx-status = #f, then tx-stack = null (except temporarily,
+    within lock). But it is possible for tx-status != #f and
+    tx-stack = null; that indicates an unmanaged tx.
     |#
 
-    ;; tx-status : #f, #t, 'invalid
-    (field [tx-status #f])
+    (define tx-status #f)
+    (define tx-stack null)
 
-    ;; tx-stack : (list (cons string boolean) ... (cons #f boolean)
-    ;; Represents the "managed" transaction stack.
-    (field [tx-stack null])
+    (define/public (get-tx-status) tx-status)
+    (define/public (set-tx-status! fsym s)
+      (set! tx-status s))
 
     ;; check-valid-tx-status : symbol -> void
     (define/public (check-valid-tx-status fsym)
@@ -192,16 +197,19 @@
 
     ;; ----
 
+    ;; (inherit call-with-lock)
+    (define/override (call-with-lock fsym proc)
+      (super call-with-lock fsym
+             (lambda ()
+               (begin0 (proc)
+                 (when (and (eq? tx-status #f) (not (null? tx-stack)))
+                   (error/internal fsym "managed transaction unexpectedly closed"))))))
+
+    ;; ----
+
     (define/public (transaction-status fsym)
       (call-with-lock fsym (lambda () tx-status)))
 
-    ;; transaction-nesting : -> (U #f 'unmanaged 'top-level 'nested)
-    (define/public (transaction-nesting)
-      (cond [(eq? tx-status #f) #f]
-            [(null? tx-stack) 'unmanaged]
-            [(null? (cdr tx-stack)) 'top-level]
-            [else 'nested]))
-
     (define/public (tx-state->string)
       (string-append (case (transaction-nesting)
                        ((#f) "not in transaction")
@@ -213,6 +221,12 @@
                                           (string-join savepoints ", "))
                            ""))))
 
+    (define/private (transaction-nesting)
+      (cond [(eq? tx-status #f) #f]
+            [(null? tx-stack) 'unmanaged]
+            [(null? (cdr tx-stack)) 'top-level]
+            [else 'nested]))
+
     ;; ----
 
     (define/public (start-transaction fsym isolation cwt?)
@@ -296,8 +310,8 @@
       if in "managed" top-level transaction (no "managed" savepoints):
        - START not allowed
        - COMMIT, ROLLBACK not allowed (for now!)
-       - SAVEPOINT allowed
-       - RELEASE TO, ROLLBACK TO allowed
+       - SAVEPOINT not allowed (for consistency, for ease of stmt cache)
+       - RELEASE TO, ROLLBACK TO not allowed (for consistency, for ease of stmt cache)
        - implicit-commit not allowed
 
       if in nested "managed" transaction (impl as "managed" savepoint):
@@ -321,15 +335,7 @@
          (void))
         ((unmanaged)
          (void))
-        ((top-level)
-         (case stmt-type
-           ((start)
-            (no! " within transaction"))
-           ((commit rollback
-             implicit-commit)
-            (no! " within managed transaction"))
-           (else (void))))
-        ((nested)
+        ((top-level nested)
          (case stmt-type
            ((start)
             (no! " within transaction"))
@@ -337,7 +343,7 @@
              savepoint prepare-transaction
              release-savepoint rollback-savepoint
              implicit-commit)
-            (no! " in managed transaction"))
+            (no! " within managed transaction"))
            (else (void))))))
 
     (super-new)))
diff --git a/collects/db/private/mysql/connection.rkt b/collects/db/private/mysql/connection.rkt
index 8f6ff681b0..57eb5b969c 100644
--- a/collects/db/private/mysql/connection.rkt
+++ b/collects/db/private/mysql/connection.rkt
@@ -26,8 +26,9 @@
              call-with-lock*
              add-delayed-call!
              check-valid-tx-status
+             get-tx-status
+             set-tx-status!
              check-statement/tx)
-    (inherit-field tx-status)
 
     (super-new)
 
@@ -97,15 +98,13 @@
           (eprintf "  << ~s\n" next))
         ;; Update transaction status (see Transactions below)
         (when (ok-packet? next)
-          (set! tx-status
-                (bitwise-bit-set? (ok-packet-server-status next) 0)))
+          (set-tx-status! fsym (bitwise-bit-set? (ok-packet-server-status next) 0)))
         (when (eof-packet? next)
-          (set! tx-status
-                (bitwise-bit-set? (eof-packet-server-status next) 0)))
+          (set-tx-status! fsym (bitwise-bit-set? (eof-packet-server-status next) 0)))
         (when (error-packet? next)
-          (when tx-status
-            (when (member (error-packet-errno next) '(1213 1205))
-              (set! tx-status 'invalid))))
+          (when (member (error-packet-errno next) '(1213 1205))
+            (when (get-tx-status)
+              (set-tx-status! fsym 'invalid))))
         (match next
           [(? handshake-packet?)
            (advance 'handshake)]
diff --git a/collects/db/private/odbc/connection.rkt b/collects/db/private/odbc/connection.rkt
index f32d6eea1e..77b77742ae 100644
--- a/collects/db/private/odbc/connection.rkt
+++ b/collects/db/private/odbc/connection.rkt
@@ -43,9 +43,10 @@
     (inherit call-with-lock
              call-with-lock*
              add-delayed-call!
+             get-tx-status
+             set-tx-status!
              check-valid-tx-status
              check-statement/tx)
-    (inherit-field tx-status)
 
     (define/public (get-db fsym)
       (unless db
@@ -539,7 +540,7 @@
           (handle-status fsym status db)))
       (let ([status (SQLSetConnectAttr db SQL_ATTR_AUTOCOMMIT SQL_AUTOCOMMIT_OFF)])
         (handle-status fsym status db)
-        (set! tx-status #t)
+        (set-tx-status! fsym #t)
         (void)))
 
     (define/override (end-transaction* fsym mode _savepoint)
@@ -553,7 +554,7 @@
         (let ([status (SQLSetConnectAttr db SQL_ATTR_AUTOCOMMIT SQL_AUTOCOMMIT_ON)])
           (handle-status fsym status db)
           ;; commit/rollback can fail; don't change status until possible error handled
-          (set! tx-status #f)
+          (set-tx-status! fsym #f)
           (void))))
 
     ;; GetTables
@@ -637,8 +638,8 @@
         ;; if the driver does one-statement rollback.
         (let ([db db])
           (when db
-            (when tx-status
-              (set! tx-status 'invalid))))
+            (when (get-tx-status)
+              (set-tx-status! who 'invalid))))
         (raise e))
       ;; Be careful: shouldn't do rollback before we call handle-status*
       ;; just in case rollback destroys statement with diagnostic records.
diff --git a/collects/db/private/postgresql/connection.rkt b/collects/db/private/postgresql/connection.rkt
index cedd379b82..efe2ccf843 100644
--- a/collects/db/private/postgresql/connection.rkt
+++ b/collects/db/private/postgresql/connection.rkt
@@ -34,11 +34,11 @@
     (inherit call-with-lock
              call-with-lock*
              add-delayed-call!
+             get-tx-status
+             set-tx-status!
              check-valid-tx-status
              check-statement/tx
-             transaction-nesting
              tx-state->string)
-    (inherit-field tx-status)
 
     (super-new)
 
@@ -105,10 +105,11 @@
       (let ([r (recv-message fsym)])
         (cond [(ReadyForQuery? r)
                ;; Update transaction status
-               (case (ReadyForQuery-transaction-status r)
-                 ((idle) (set! tx-status #f))
-                 ((transaction) (set! tx-status #t))
-                 ((failed) (set! tx-status 'invalid)))]
+               (set-tx-status! fsym
+                               (case (ReadyForQuery-transaction-status r)
+                                 ((idle) #f)
+                                 ((transaction) #t)
+                                 ((failed) 'invalid)))]
               [(and or-eof? (eof-object? r)) (void)]
               [else (error/comm fsym "expected ready")])))
 
diff --git a/collects/db/private/sqlite3/connection.rkt b/collects/db/private/sqlite3/connection.rkt
index a084c29040..edcc0a5c91 100644
--- a/collects/db/private/sqlite3/connection.rkt
+++ b/collects/db/private/sqlite3/connection.rkt
@@ -25,12 +25,13 @@
 
     (inherit call-with-lock*
              add-delayed-call!
+             get-tx-status
+             set-tx-status!
              check-valid-tx-status
              check-statement/tx)
-    (inherit-field tx-status)
 
     (define/override (call-with-lock fsym proc)
-      (call-with-lock* fsym (lambda () (set! saved-tx-status tx-status) (proc)) #f #t))
+      (call-with-lock* fsym (lambda () (set! saved-tx-status (get-tx-status)) (proc)) #f #t))
 
     (define/private (get-db fsym)
       (or -db (error/not-connected fsym)))
@@ -63,8 +64,8 @@
                 [result
                  (or cursor?
                      (step* fsym db stmt #f +inf.0))])
-            (unless (eq? tx-status 'invalid)
-              (set! tx-status (get-tx-status)))
+            (unless (eq? (get-tx-status) 'invalid)
+              (set-tx-status! fsym (read-tx-status)))
             (unless cursor? (send pst after-exec #f))
             (cond [(and (pair? info) (not cursor?))
                    (rows-result info result)]
@@ -223,7 +224,7 @@
 
     ;; http://www.sqlite.org/lang_transaction.html
 
-    (define/private (get-tx-status)
+    (define/private (read-tx-status)
       (not (sqlite3_get_autocommit -db)))
 
     (define/override (start-transaction* fsym isolation)
@@ -252,7 +253,7 @@
                [else
                 (internal-query1 fsym "ROLLBACK TRANSACTION")])
          ;; remove 'invalid status, if necessary
-         (set! tx-status (get-tx-status))))
+         (set-tx-status! fsym (read-tx-status))))
       (void))
 
     ;; name-counter : number
@@ -295,8 +296,8 @@
     ;; Can't figure out how to test...
     (define/private (handle-status who s)
       (when (memv s maybe-rollback-status-list)
-        (when (and saved-tx-status -db (not (get-tx-status))) ;; was in trans, now not
-          (set! tx-status 'invalid)))
+        (when (and saved-tx-status -db (not (read-tx-status))) ;; was in trans, now not
+          (set-tx-status! who 'invalid)))
       (handle-status* who s -db))
 
     ;; ----