Index: src/db.c
==================================================================
--- src/db.c
+++ src/db.c
@@ -1276,10 +1276,13 @@
   if( g.fSqlTrace ) sqlite3_trace_v2(db, SQLITE_TRACE_PROFILE, db_sql_trace, 0);
   db_add_aux_functions(db);
   re_add_sql_func(db);  /* The REGEXP operator */
   foci_register(db);    /* The "files_of_checkin" virtual table */
   sqlite3_exec(db, "PRAGMA foreign_keys=OFF;", 0, 0, 0);
+#if USE_SYSTEM_SQLITE+0==1
+  sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, g.maxWorkerThreads);
+#endif
   return db;
 }
 
 
 /*
@@ -1766,10 +1769,14 @@
   sqlite3_file_control(g.db, "repository", SQLITE_FCNTL_DATA_VERSION,
                        &g.iRepoDataVers);
   /* Cache "allow-symlinks" option, because we'll need it on every stat call */
   g.allowSymlinks = db_get_boolean("allow-symlinks",
                                    db_allow_symlinks_by_default());
+  /* Cache "max-wthreads" option */
+#if USE_SYSTEM_SQLITE+0==1
+  g.maxWorkerThreads = db_get_int("max-wthreads", 0);
+#endif
   g.zAuxSchema = db_get("aux-schema","");
   g.eHashPolicy = db_get_int("hash-policy",-1);
   if( g.eHashPolicy<0 ){
     g.eHashPolicy = hname_default_policy();
     db_set_int("hash-policy", g.eHashPolicy, 0);
@@ -3540,10 +3547,19 @@
 */
 /*
 ** SETTING: max-upload       width=25 default=250000
 ** A limit on the size of uplink HTTP requests.
 */
+#if USE_SYSTEM_SQLITE+0==1
+/*
+** SETTING: max-wthreads     width=16 default=0
+** The maximum number of auxiliary worker threads that a
+** single prepared statement may start.  Only works when
+** using the system SQLite library and when that library
+** was compiled with support for threading.
+*/
+#endif
 /*
 ** SETTING: mimetypes        width=40 versionable block-text
 ** A list of file extension-to-mimetype mappings, one per line. e.g.
 ** "foo application/x-foo". File extensions are compared
 ** case-insensitively in the order listed in this setting.  A leading

Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -312,10 +312,13 @@
     } reqPayload;              /* request payload object (if any) */
     cson_array *warnings;      /* response warnings */
     int timerId;               /* fetched from fossil_timer_start() */
   } json;
 #endif /* FOSSIL_ENABLE_JSON */
+#if USE_SYSTEM_SQLITE+0==1
+  int maxWorkerThreads;          /* Cached "max-wthreads" option */
+#endif
 };
 
 /*
 ** Macro for debugging:
 */

Index: src/sqlcmd.c
==================================================================
--- src/sqlcmd.c
+++ src/sqlcmd.c
@@ -165,10 +165,13 @@
   sqlite3 *db,
   const char **pzErrMsg,
   const void *notUsed
 ){
   int mTrace = SQLITE_TRACE_CLOSE;
+#if USE_SYSTEM_SQLITE+0==1
+  sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, g.maxWorkerThreads);
+#endif
   add_content_sql_commands(db);
   db_add_aux_functions(db);
   re_add_sql_func(db);
   search_sql_setup(db);
   foci_register(db);