Index: ext/rbu/rbuprogress.test
==================================================================
--- ext/rbu/rbuprogress.test
+++ ext/rbu/rbuprogress.test
@@ -411,8 +411,40 @@
       set R(vtab) $r2
       do_sp_test 5.$tn.$bReopen.$tn2.1 $bReopen test.db rbu.db $R($tn)
     }
   }
 }
+
+#-------------------------------------------------------------------------
+# Test that sqlite3_bp_progress() works with an RBU vacuum if there
+# is an rbu_count table in the db being vacuumed.
+#
+reset_db
+do_execsql_test 6.0 {
+  CREATE TABLE t1(a, b, c);
+  CREATE INDEX i1 ON t1(a);
+  CREATE INDEX i2 ON t1(b);
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
+  )
+  INSERT INTO t1 SELECT i, i, i FROM s;
+  CREATE TABLE rbu_count(tbl TEXT PRIMARY KEY, cnt INTEGER) WITHOUT ROWID;
+  INSERT INTO rbu_count VALUES('t1', (SELECT count(*) FROM t1));
+  INSERT INTO rbu_count VALUES('rbu_count', 2);
+}
+
+forcedelete state.db
+do_test 6.1 {
+  set maxA 0
+  set maxB 0
+  sqlite3rbu_vacuum rbu test.db state.db
+  while {[rbu step]=="SQLITE_OK"} {
+    foreach {a b} [rbu bp_progress] {
+      if {$a > $maxA} { set maxA $a }
+      if {$b > $maxB} { set maxB $b }
+    }
+  }
+  list [rbu close] $maxA $maxB
+} {SQLITE_DONE 10000 10000}
 
 
 finish_test

Index: ext/rbu/sqlite3rbu.c
==================================================================
--- ext/rbu/sqlite3rbu.c
+++ ext/rbu/sqlite3rbu.c
@@ -942,12 +942,12 @@
   assert( argc==1 || argc==2 );
 
   zIn = (const char*)sqlite3_value_text(argv[0]);
   if( zIn ){
     if( rbuIsVacuum(p) ){
-      assert( argc==2 );
-      if( 0==sqlite3_value_int(argv[1]) ){
+      assert( argc==2 || argc==1 );
+      if( argc==1 || 0==sqlite3_value_int(argv[1]) ){
         sqlite3_result_text(pCtx, zIn, -1, SQLITE_STATIC);
       }
     }else{
       if( strlen(zIn)>4 && memcmp("data", zIn, 4)==0 ){
         int i;
@@ -3858,14 +3858,15 @@
 ){
   sqlite3rbu *p = (sqlite3rbu*)sqlite3_user_data(pCtx);
   sqlite3_stmt *pStmt = 0;
   char *zErrmsg = 0;
   int rc;
+  sqlite3 *db = (rbuIsVacuum(p) ? p->dbRbu : p->dbMain);
 
   assert( nVal==1 );
   
-  rc = prepareFreeAndCollectError(p->dbMain, &pStmt, &zErrmsg, 
+  rc = prepareFreeAndCollectError(db, &pStmt, &zErrmsg, 
       sqlite3_mprintf("SELECT count(*) FROM sqlite_master "
         "WHERE type='index' AND tbl_name = %Q", sqlite3_value_text(apVal[0]))
   );
   if( rc!=SQLITE_OK ){
     sqlite3_result_error(pCtx, zErrmsg, -1);
@@ -3876,11 +3877,11 @@
     }
     rc = sqlite3_finalize(pStmt);
     if( rc==SQLITE_OK ){
       sqlite3_result_int(pCtx, nIndex);
     }else{
-      sqlite3_result_error(pCtx, sqlite3_errmsg(p->dbMain), -1);
+      sqlite3_result_error(pCtx, sqlite3_errmsg(db), -1);
     }
   }
 
   sqlite3_free(zErrmsg);
 }