X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=ovsdb%2Fjsonrpc-server.c;h=caaf2bf497ad57574adda4ca7f9b7699bcac6fc4;hb=HEAD;hp=379fc524d5eec3c2519e53880552705ca8e53607;hpb=b2fda3effc787f265b5ad5dfa967ac00627bd075;p=cascardo%2Fovs.git

diff --git a/ovsdb/jsonrpc-server.c b/ovsdb/jsonrpc-server.c
index 379fc524d..caaf2bf49 100644
--- a/ovsdb/jsonrpc-server.c
+++ b/ovsdb/jsonrpc-server.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2011 Nicira Networks
+/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,30 +17,38 @@
 
 #include "jsonrpc-server.h"
 
-#include <assert.h>
 #include <errno.h>
 
 #include "bitmap.h"
 #include "column.h"
+#include "dynamic-string.h"
+#include "monitor.h"
 #include "json.h"
 #include "jsonrpc.h"
 #include "ovsdb-error.h"
 #include "ovsdb-parser.h"
 #include "ovsdb.h"
+#include "poll-loop.h"
 #include "reconnect.h"
 #include "row.h"
+#include "server.h"
+#include "simap.h"
 #include "stream.h"
 #include "table.h"
 #include "timeval.h"
 #include "transaction.h"
 #include "trigger.h"
-#include "vlog.h"
+#include "openvswitch/vlog.h"
 
 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
 
 struct ovsdb_jsonrpc_remote;
 struct ovsdb_jsonrpc_session;
 
+/* Set false to defeature monitor2, causing jsonrpc to respond to monitor2
+ * method with an error.  */
+static bool monitor2_enable__ = true;
+
 /* Message rate-limiting. */
 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
 
@@ -49,16 +57,26 @@ static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
+static void ovsdb_jsonrpc_session_get_memory_usage_all(
+    const struct ovsdb_jsonrpc_remote *, struct simap *usage);
 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
 static void ovsdb_jsonrpc_session_set_all_options(
     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
-static void ovsdb_jsonrpc_session_get_status(
+static bool ovsdb_jsonrpc_active_session_get_status(
     const struct ovsdb_jsonrpc_remote *,
-    struct shash *);
+    struct ovsdb_jsonrpc_remote_status *);
+static void ovsdb_jsonrpc_session_get_status(
+    const struct ovsdb_jsonrpc_session *,
+    struct ovsdb_jsonrpc_remote_status *);
+static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
+static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
+static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
+                                       struct jsonrpc_msg *);
 
 /* Triggers. */
 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
+                                         struct ovsdb *,
                                          struct json *id, struct json *params);
 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
@@ -68,19 +86,25 @@ static void ovsdb_jsonrpc_trigger_complete_done(
     struct ovsdb_jsonrpc_session *);
 
 /* Monitors. */
-static struct json *ovsdb_jsonrpc_monitor_create(
-    struct ovsdb_jsonrpc_session *, struct json *params);
+static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
+    struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
+    enum ovsdb_monitor_version, const struct json *request_id);
 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
     struct ovsdb_jsonrpc_session *,
     struct json_array *params,
     const struct json *request_id);
 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
+static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
+static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
+static struct json *ovsdb_jsonrpc_monitor_compose_update(
+    struct ovsdb_jsonrpc_monitor *monitor, bool initial);
+
 
 /* JSON-RPC database server. */
 
 struct ovsdb_jsonrpc_server {
-    struct ovsdb *db;
-    unsigned int n_sessions, max_sessions;
+    struct ovsdb_server up;
+    unsigned int n_sessions;
     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
 };
 
@@ -90,23 +114,65 @@ struct ovsdb_jsonrpc_server {
 struct ovsdb_jsonrpc_remote {
     struct ovsdb_jsonrpc_server *server;
     struct pstream *listener;   /* Listener, if passive. */
-    struct list sessions;       /* List of "struct ovsdb_jsonrpc_session"s. */
+    struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
+    uint8_t dscp;
 };
 
 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
-    struct ovsdb_jsonrpc_server *, const char *name);
+    struct ovsdb_jsonrpc_server *, const char *name,
+    const struct ovsdb_jsonrpc_options *options
+);
 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 
+/* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
+ *
+ * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
+ * which 'server' should provide access. */
 struct ovsdb_jsonrpc_server *
-ovsdb_jsonrpc_server_create(struct ovsdb *db)
+ovsdb_jsonrpc_server_create(void)
 {
     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
-    server->db = db;
-    server->max_sessions = 64;
+    ovsdb_server_init(&server->up);
     shash_init(&server->remotes);
     return server;
 }
 
+/* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
+ * successful, false if 'db''s name is the same as some database already in
+ * 'server'. */
+bool
+ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
+{
+    /* The OVSDB protocol doesn't have a way to notify a client that a
+     * database has been added.  If some client tried to use the database
+     * that we're adding and failed, then forcing it to reconnect seems like
+     * a reasonable way to make it try again.
+     *
+     * If this is too big of a hammer in practice, we could be more selective,
+     * e.g. disconnect only connections that actually tried to use a database
+     * with 'db''s name. */
+    ovsdb_jsonrpc_server_reconnect(svr);
+
+    return ovsdb_server_add_db(&svr->up, db);
+}
+
+/* Removes 'db' from the set of databases served out by 'svr'.  Returns
+ * true if successful, false if there is no database associated with 'db'. */
+bool
+ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
+                               struct ovsdb *db)
+{
+    /* There might be pointers to 'db' from 'svr', such as monitors or
+     * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
+     * accesses to freed memory.
+     *
+     * If this is too big of a hammer in practice, we could be more selective,
+     * e.g. disconnect only connections that actually reference 'db'. */
+    ovsdb_jsonrpc_server_reconnect(svr);
+
+    return ovsdb_server_remove_db(&svr->up, db);
+}
+
 void
 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 {
@@ -116,15 +182,18 @@ ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
         ovsdb_jsonrpc_server_del_remote(node);
     }
     shash_destroy(&svr->remotes);
+    ovsdb_server_destroy(&svr->up);
     free(svr);
 }
 
 struct ovsdb_jsonrpc_options *
-ovsdb_jsonrpc_default_options(void)
+ovsdb_jsonrpc_default_options(const char *target)
 {
     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
-    options->probe_interval = RECONNECT_DEFAULT_PROBE_INTERVAL;
     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
+    options->probe_interval = (stream_or_pstream_needs_probes(target)
+                               ? RECONNECT_DEFAULT_PROBE_INTERVAL
+                               : 0);
     return options;
 }
 
@@ -140,9 +209,16 @@ ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
     struct shash_node *node, *next;
 
     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
-        if (!shash_find(new_remotes, node->name)) {
+        struct ovsdb_jsonrpc_remote *remote = node->data;
+        struct ovsdb_jsonrpc_options *options
+            = shash_find_data(new_remotes, node->name);
+
+        if (!options) {
+            VLOG_INFO("%s: remote deconfigured", node->name);
             ovsdb_jsonrpc_server_del_remote(node);
-        }
+        } else if (options->dscp != remote->dscp) {
+            ovsdb_jsonrpc_server_del_remote(node);
+         }
     }
     SHASH_FOR_EACH (node, new_remotes) {
         const struct ovsdb_jsonrpc_options *options = node->data;
@@ -150,7 +226,7 @@ ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 
         remote = shash_find_data(&svr->remotes, node->name);
         if (!remote) {
-            remote = ovsdb_jsonrpc_server_add_remote(svr, node->name);
+            remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
             if (!remote) {
                 continue;
             }
@@ -162,15 +238,16 @@ ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 
 static struct ovsdb_jsonrpc_remote *
 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
-                                const char *name)
+                                const char *name,
+                                const struct ovsdb_jsonrpc_options *options)
 {
     struct ovsdb_jsonrpc_remote *remote;
     struct pstream *listener;
     int error;
 
-    error = jsonrpc_pstream_open(name, &listener);
+    error = jsonrpc_pstream_open(name, &listener, options->dscp);
     if (error && error != EAFNOSUPPORT) {
-        VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
+        VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
         return NULL;
     }
 
@@ -178,10 +255,11 @@ ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
     remote->server = svr;
     remote->listener = listener;
     list_init(&remote->sessions);
+    remote->dscp = options->dscp;
     shash_add(&svr->remotes, name, remote);
 
     if (!listener) {
-        ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
+        ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
     }
     return remote;
 }
@@ -197,19 +275,44 @@ ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
     free(remote);
 }
 
-void
-ovsdb_jsonrpc_server_get_remote_status(const struct ovsdb_jsonrpc_server *svr,
-                                       struct shash *statuses)
+/* Stores status information for the remote named 'target', which should have
+ * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
+ * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
+ * a remote named 'target' or if that remote is an outbound remote that has no
+ * active connections) returns false.  On failure, 'status' will be zeroed.
+ */
+bool
+ovsdb_jsonrpc_server_get_remote_status(
+    const struct ovsdb_jsonrpc_server *svr, const char *target,
+    struct ovsdb_jsonrpc_remote_status *status)
 {
-    struct shash_node *node;
+    const struct ovsdb_jsonrpc_remote *remote;
 
-    shash_init(statuses);
+    memset(status, 0, sizeof *status);
 
-    SHASH_FOR_EACH (node, &svr->remotes) {
-        const struct ovsdb_jsonrpc_remote *remote = node->data;
+    remote = shash_find_data(&svr->remotes, target);
 
-        ovsdb_jsonrpc_session_get_status(remote, statuses);
+    if (!remote) {
+        return false;
+    }
+
+    if (remote->listener) {
+        status->bound_port = pstream_get_bound_port(remote->listener);
+        status->is_connected = !list_is_empty(&remote->sessions);
+        status->n_connections = list_size(&remote->sessions);
+        return true;
     }
+
+    return ovsdb_jsonrpc_active_session_get_status(remote, status);
+}
+
+void
+ovsdb_jsonrpc_server_free_remote_status(
+    struct ovsdb_jsonrpc_remote_status *status)
+{
+    free(status->locks_held);
+    free(status->locks_waiting);
+    free(status->locks_lost);
 }
 
 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
@@ -234,19 +337,20 @@ ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
     SHASH_FOR_EACH (node, &svr->remotes) {
         struct ovsdb_jsonrpc_remote *remote = node->data;
 
-        if (remote->listener && svr->n_sessions < svr->max_sessions) {
+        if (remote->listener) {
             struct stream *stream;
             int error;
 
             error = pstream_accept(remote->listener, &stream);
             if (!error) {
                 struct jsonrpc_session *js;
-                js = jsonrpc_session_open_unreliably(jsonrpc_open(stream));
+                js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
+                                                     remote->dscp);
                 ovsdb_jsonrpc_session_create(remote, js);
             } else if (error != EAGAIN) {
                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
                              pstream_get_name(remote->listener),
-                             strerror(error));
+                             ovs_strerror(error));
             }
         }
 
@@ -262,23 +366,39 @@ ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
     SHASH_FOR_EACH (node, &svr->remotes) {
         struct ovsdb_jsonrpc_remote *remote = node->data;
 
-        if (remote->listener && svr->n_sessions < svr->max_sessions) {
+        if (remote->listener) {
             pstream_wait(remote->listener);
         }
 
         ovsdb_jsonrpc_session_wait_all(remote);
     }
 }
+
+/* Adds some memory usage statistics for 'svr' into 'usage', for use with
+ * memory_report(). */
+void
+ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
+                                      struct simap *usage)
+{
+    struct shash_node *node;
+
+    simap_increase(usage, "sessions", svr->n_sessions);
+    SHASH_FOR_EACH (node, &svr->remotes) {
+        struct ovsdb_jsonrpc_remote *remote = node->data;
+
+        ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
+    }
+}
 
 /* JSON-RPC database server session. */
 
 struct ovsdb_jsonrpc_session {
+    struct ovs_list node;       /* Element in remote's sessions list. */
+    struct ovsdb_session up;
     struct ovsdb_jsonrpc_remote *remote;
-    struct list node;           /* Element in remote's sessions list. */
 
     /* Triggers. */
     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
-    struct list completions;    /* Completed triggers. */
 
     /* Monitors. */
     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
@@ -291,8 +411,8 @@ struct ovsdb_jsonrpc_session {
 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
-static void ovsdb_jsonrpc_session_set_options(
-    struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *);
+static void ovsdb_jsonrpc_session_get_memory_usage(
+    const struct ovsdb_jsonrpc_session *, struct simap *usage);
 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
                                              struct jsonrpc_msg *);
 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
@@ -305,11 +425,11 @@ ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
     struct ovsdb_jsonrpc_session *s;
 
     s = xzalloc(sizeof *s);
+    ovsdb_session_init(&s->up, &remote->server->up);
     s->remote = remote;
     list_push_back(&remote->sessions, &s->node);
     hmap_init(&s->triggers);
     hmap_init(&s->monitors);
-    list_init(&s->completions);
     s->js = js;
     s->js_seqno = jsonrpc_session_get_seqno(js);
 
@@ -322,9 +442,16 @@ static void
 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 {
     ovsdb_jsonrpc_monitor_remove_all(s);
+    ovsdb_jsonrpc_session_unlock_all(s);
+    ovsdb_jsonrpc_trigger_complete_all(s);
+
+    hmap_destroy(&s->monitors);
+    hmap_destroy(&s->triggers);
+
     jsonrpc_session_close(s->js);
     list_remove(&s->node);
     s->remote->server->n_sessions--;
+    ovsdb_session_destroy(&s->up);
     free(s);
 }
 
@@ -336,12 +463,17 @@ ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
         s->js_seqno = jsonrpc_session_get_seqno(s->js);
         ovsdb_jsonrpc_trigger_complete_all(s);
         ovsdb_jsonrpc_monitor_remove_all(s);
+        ovsdb_jsonrpc_session_unlock_all(s);
     }
 
     ovsdb_jsonrpc_trigger_complete_done(s);
 
     if (!jsonrpc_session_get_backlog(s->js)) {
-        struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
+        struct jsonrpc_msg *msg;
+
+        ovsdb_jsonrpc_monitor_flush_all(s);
+
+        msg = jsonrpc_session_recv(s->js);
         if (msg) {
             if (msg->type == JSONRPC_REQUEST) {
                 ovsdb_jsonrpc_session_got_request(s, msg);
@@ -365,6 +497,7 @@ ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 {
     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
+    jsonrpc_session_set_dscp(session->js, options->dscp);
 }
 
 static void
@@ -385,7 +518,11 @@ ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 {
     jsonrpc_session_wait(s->js);
     if (!jsonrpc_session_get_backlog(s->js)) {
-        jsonrpc_session_recv_wait(s->js);
+        if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
+            poll_immediate_wake();
+        } else {
+            jsonrpc_session_recv_wait(s->js);
+        }
     }
 }
 
@@ -399,6 +536,26 @@ ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
     }
 }
 
+static void
+ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
+                                       struct simap *usage)
+{
+    simap_increase(usage, "triggers", hmap_count(&s->triggers));
+    simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
+}
+
+static void
+ovsdb_jsonrpc_session_get_memory_usage_all(
+    const struct ovsdb_jsonrpc_remote *remote,
+    struct simap *usage)
+{
+    struct ovsdb_jsonrpc_session *s;
+
+    LIST_FOR_EACH (s, node, &remote->sessions) {
+        ovsdb_jsonrpc_session_get_memory_usage(s, usage);
+    }
+}
+
 static void
 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 {
@@ -425,7 +582,10 @@ ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 }
 
 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
- * 'options'. */
+ * 'options'.
+ *
+ * (The dscp value can't be changed directly; the caller must instead close and
+ * re-open the session.) */
 static void
 ovsdb_jsonrpc_session_set_all_options(
     struct ovsdb_jsonrpc_remote *remote,
@@ -438,32 +598,38 @@ ovsdb_jsonrpc_session_set_all_options(
     }
 }
 
-static void
-ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
-                                 struct shash *shash)
+/* Sets the 'status' of for the 'remote' with an outgoing connection.   */
+static bool
+ovsdb_jsonrpc_active_session_get_status(
+    const struct ovsdb_jsonrpc_remote *remote,
+    struct ovsdb_jsonrpc_remote_status *status)
 {
+    const struct ovs_list *sessions = &remote->sessions;
     const struct ovsdb_jsonrpc_session *s;
+
+    if (list_is_empty(sessions)) {
+        return false;
+    }
+
+    ovs_assert(list_is_singleton(sessions));
+    s = CONTAINER_OF(list_front(sessions), struct ovsdb_jsonrpc_session, node);
+    ovsdb_jsonrpc_session_get_status(s, status);
+    status->n_connections = 1;
+
+    return true;
+}
+
+static void
+ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_session *session,
+                                 struct ovsdb_jsonrpc_remote_status *status)
+{
+    const struct ovsdb_jsonrpc_session *s = session;
     const struct jsonrpc_session *js;
-    const char *name;
-    struct ovsdb_jsonrpc_remote_status *status;
+    struct ovsdb_lock_waiter *waiter;
     struct reconnect_stats rstats;
+    struct ds locks_held, locks_waiting, locks_lost;
 
-    /* We only look at the first session in the list. There should be only one
-     * node in the list for outbound connections. We don't track status for
-     * each individual inbound connection if someone configures the DB that
-     * way. Since outbound connections are the norm, this is fine. */
-    if (list_is_empty(&remote->sessions)) {
-        return;
-    }
-    s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
     js = s->js;
-    if (!js) {
-        return;
-    }
-    name = jsonrpc_session_get_name(js);
-
-    status = xzalloc(sizeof *status);
-    shash_add(shash, name, status);
 
     status->is_connected = jsonrpc_session_is_connected(js);
     status->last_error = jsonrpc_session_get_status(js);
@@ -475,24 +641,41 @@ ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 
-    return;
-}
-
-static const char *
-get_db_name(const struct ovsdb_jsonrpc_session *s)
-{
-    return s->remote->server->db->schema->name;
+    ds_init(&locks_held);
+    ds_init(&locks_waiting);
+    ds_init(&locks_lost);
+    HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
+        struct ds *string;
+
+        string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
+                  : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
+                  : &locks_lost);
+        if (string->length) {
+            ds_put_char(string, ' ');
+        }
+        ds_put_cstr(string, waiter->lock_name);
+    }
+    status->locks_held = ds_steal_cstr(&locks_held);
+    status->locks_waiting = ds_steal_cstr(&locks_waiting);
+    status->locks_lost = ds_steal_cstr(&locks_lost);
 }
 
-static struct jsonrpc_msg *
-ovsdb_jsonrpc_check_db_name(const struct ovsdb_jsonrpc_session *s,
-                            const struct jsonrpc_msg *request)
+/* Examines 'request' to determine the database to which it relates, and then
+ * searches 's' to find that database:
+ *
+ *    - If successful, returns the database and sets '*replyp' to NULL.
+ *
+ *    - If no such database exists, returns NULL and sets '*replyp' to an
+ *      appropriate JSON-RPC error reply, owned by the caller. */
+static struct ovsdb *
+ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
+                        const struct jsonrpc_msg *request,
+                        struct jsonrpc_msg **replyp)
 {
     struct json_array *params;
-    const char *want_db_name;
-    const char *have_db_name;
     struct ovsdb_error *error;
-    struct jsonrpc_msg *reply;
+    const char *db_name;
+    struct ovsdb *db;
 
     params = json_array(request->params);
     if (!params->n || params->elems[0]->type != JSON_STRING) {
@@ -502,29 +685,168 @@ ovsdb_jsonrpc_check_db_name(const struct ovsdb_jsonrpc_session *s,
         goto error;
     }
 
-    want_db_name = params->elems[0]->u.string;
-    have_db_name = get_db_name(s);
-    if (strcmp(want_db_name, have_db_name)) {
+    db_name = params->elems[0]->u.string;
+    db = shash_find_data(&s->up.server->dbs, db_name);
+    if (!db) {
         error = ovsdb_syntax_error(
             request->params, "unknown database",
             "%s request specifies unknown database %s",
-            request->method, want_db_name);
+            request->method, db_name);
         goto error;
     }
 
+    *replyp = NULL;
+    return db;
+
+error:
+    *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
+    ovsdb_error_destroy(error);
     return NULL;
+}
+
+static struct ovsdb_error *
+ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
+                                      const char **lock_namep)
+{
+    const struct json_array *params;
+
+    params = json_array(request->params);
+    if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
+        !ovsdb_parser_is_id(json_string(params->elems[0]))) {
+        *lock_namep = NULL;
+        return ovsdb_syntax_error(request->params, NULL,
+                                  "%s request params must be <id>",
+                                  request->method);
+    }
+
+    *lock_namep = json_string(params->elems[0]);
+    return NULL;
+}
+
+static void
+ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
+                             const char *lock_name,
+                             const char *method)
+{
+    struct ovsdb_jsonrpc_session *s;
+    struct json *params;
+
+    s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
+    params = json_array_create_1(json_string_create(lock_name));
+    ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
+}
+
+static struct jsonrpc_msg *
+ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
+                           struct jsonrpc_msg *request,
+                           enum ovsdb_lock_mode mode)
+{
+    struct ovsdb_lock_waiter *waiter;
+    struct jsonrpc_msg *reply;
+    struct ovsdb_error *error;
+    struct ovsdb_session *victim;
+    const char *lock_name;
+    struct json *result;
+
+    error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
+    if (error) {
+        goto error;
+    }
+
+    /* Report error if this session has issued a "lock" or "steal" without a
+     * matching "unlock" for this lock. */
+    waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
+    if (waiter) {
+        error = ovsdb_syntax_error(
+            request->params, NULL,
+            "must issue \"unlock\" before new \"%s\"", request->method);
+        goto error;
+    }
+
+    /* Get the lock, add us as a waiter. */
+    waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
+                               &victim);
+    if (victim) {
+        ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
+    }
+
+    result = json_object_create();
+    json_object_put(result, "locked",
+                    json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
+
+    return jsonrpc_create_reply(result, request->id);
 
 error:
-    reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
+    reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
     ovsdb_error_destroy(error);
     return reply;
 }
 
+static void
+ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
+{
+    struct ovsdb_lock_waiter *waiter, *next;
+
+    HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
+        ovsdb_jsonrpc_session_unlock__(waiter);
+    }
+}
+
+static void
+ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
+{
+    struct ovsdb_lock *lock = waiter->lock;
+
+    if (lock) {
+        struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
+        if (new_owner) {
+            ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
+        } else {
+            /* ovsdb_server_lock() might have freed 'lock'. */
+        }
+    }
+
+    ovsdb_lock_waiter_destroy(waiter);
+}
+
 static struct jsonrpc_msg *
-execute_transaction(struct ovsdb_jsonrpc_session *s,
+ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
+                             struct jsonrpc_msg *request)
+{
+    struct ovsdb_lock_waiter *waiter;
+    struct jsonrpc_msg *reply;
+    struct ovsdb_error *error;
+    const char *lock_name;
+
+    error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
+    if (error) {
+        goto error;
+    }
+
+    /* Report error if this session has not issued a "lock" or "steal" for this
+     * lock. */
+    waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
+    if (!waiter) {
+        error = ovsdb_syntax_error(
+            request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
+        goto error;
+    }
+
+    ovsdb_jsonrpc_session_unlock__(waiter);
+
+    return jsonrpc_create_reply(json_object_create(), request->id);
+
+error:
+    reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
+    ovsdb_error_destroy(error);
+    return reply;
+}
+
+static struct jsonrpc_msg *
+execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
                     struct jsonrpc_msg *request)
 {
-    ovsdb_jsonrpc_trigger_create(s, request->id, request->params);
+    ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
     request->id = NULL;
     request->params = NULL;
     jsonrpc_msg_destroy(request);
@@ -538,30 +860,48 @@ ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
     struct jsonrpc_msg *reply;
 
     if (!strcmp(request->method, "transact")) {
-        reply = ovsdb_jsonrpc_check_db_name(s, request);
+        struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
         if (!reply) {
-            reply = execute_transaction(s, request);
+            reply = execute_transaction(s, db, request);
         }
-    } else if (!strcmp(request->method, "monitor")) {
-        reply = ovsdb_jsonrpc_check_db_name(s, request);
+    } else if (!strcmp(request->method, "monitor") ||
+               (monitor2_enable__ && !strcmp(request->method, "monitor2"))) {
+        struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
         if (!reply) {
-            reply = jsonrpc_create_reply(
-                ovsdb_jsonrpc_monitor_create(s, request->params), request->id);
+            int l = strlen(request->method) - strlen("monitor");
+            enum ovsdb_monitor_version version = l ? OVSDB_MONITOR_V2
+                                                   : OVSDB_MONITOR_V1;
+            reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
+                                                 version, request->id);
         }
     } else if (!strcmp(request->method, "monitor_cancel")) {
         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
                                              request->id);
     } else if (!strcmp(request->method, "get_schema")) {
-        reply = ovsdb_jsonrpc_check_db_name(s, request);
+        struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
         if (!reply) {
-            reply = jsonrpc_create_reply(
-                ovsdb_schema_to_json(s->remote->server->db->schema),
-                request->id);
+            reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
+                                         request->id);
         }
     } else if (!strcmp(request->method, "list_dbs")) {
-        reply = jsonrpc_create_reply(
-            json_array_create_1(json_string_create(get_db_name(s))),
-            request->id);
+        size_t n_dbs = shash_count(&s->up.server->dbs);
+        struct shash_node *node;
+        struct json **dbs;
+        size_t i;
+
+        dbs = xmalloc(n_dbs * sizeof *dbs);
+        i = 0;
+        SHASH_FOR_EACH (node, &s->up.server->dbs) {
+            dbs[i++] = json_string_create(node->name);
+        }
+        reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
+                                     request->id);
+    } else if (!strcmp(request->method, "lock")) {
+        reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
+    } else if (!strcmp(request->method, "steal")) {
+        reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
+    } else if (!strcmp(request->method, "unlock")) {
+        reply = ovsdb_jsonrpc_session_unlock(s, request);
     } else if (!strcmp(request->method, "echo")) {
         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
     } else {
@@ -571,7 +911,7 @@ ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 
     if (reply) {
         jsonrpc_msg_destroy(request);
-        jsonrpc_session_send(s->js, reply);
+        ovsdb_jsonrpc_session_send(s, reply);
     }
 }
 
@@ -599,6 +939,14 @@ ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
     }
     jsonrpc_msg_destroy(request);
 }
+
+static void
+ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
+                           struct jsonrpc_msg *msg)
+{
+    ovsdb_jsonrpc_monitor_flush_all(s);
+    jsonrpc_session_send(s->js, msg);
+}
 
 /* JSON-RPC database server triggers.
  *
@@ -607,13 +955,12 @@ ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 
 struct ovsdb_jsonrpc_trigger {
     struct ovsdb_trigger trigger;
-    struct ovsdb_jsonrpc_session *session;
     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
     struct json *id;
 };
 
 static void
-ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
+ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
                              struct json *id, struct json *params)
 {
     struct ovsdb_jsonrpc_trigger *t;
@@ -627,7 +974,7 @@ ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
 
         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
                                    id);
-        jsonrpc_session_send(s->js, msg);
+        ovsdb_jsonrpc_session_send(s, msg);
         json_destroy(id);
         json_destroy(params);
         return;
@@ -635,10 +982,7 @@ ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
 
     /* Insert into trigger table. */
     t = xmalloc(sizeof *t);
-    ovsdb_trigger_init(s->remote->server->db,
-                       &t->trigger, params, &s->completions,
-                       time_msec());
-    t->session = s;
+    ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
     t->id = id;
     hmap_insert(&s->triggers, &t->hmap_node, hash);
 
@@ -666,7 +1010,9 @@ ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 static void
 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 {
-    struct ovsdb_jsonrpc_session *s = t->session;
+    struct ovsdb_jsonrpc_session *s;
+
+    s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 
     if (jsonrpc_session_is_connected(s->js)) {
         struct jsonrpc_msg *reply;
@@ -679,7 +1025,7 @@ ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
             reply = jsonrpc_create_error(json_string_create("canceled"),
                                          t->id);
         }
-        jsonrpc_session_send(s->js, reply);
+        ovsdb_jsonrpc_session_send(s, reply);
     }
 
     json_destroy(t->id);
@@ -700,70 +1046,27 @@ ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 static void
 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 {
-    while (!list_is_empty(&s->completions)) {
+    while (!list_is_empty(&s->up.completions)) {
         struct ovsdb_jsonrpc_trigger *t
-            = CONTAINER_OF(s->completions.next,
+            = CONTAINER_OF(s->up.completions.next,
                            struct ovsdb_jsonrpc_trigger, trigger.node);
         ovsdb_jsonrpc_trigger_complete(t);
     }
 }
 
-/* JSON-RPC database table monitors. */
-
-enum ovsdb_jsonrpc_monitor_selection {
-    OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
-    OJMS_INSERT = 1 << 1,       /* New rows. */
-    OJMS_DELETE = 1 << 2,       /* Deleted rows. */
-    OJMS_MODIFY = 1 << 3        /* Modified rows. */
-};
-
-/* A particular column being monitored. */
-struct ovsdb_jsonrpc_monitor_column {
-    const struct ovsdb_column *column;
-    enum ovsdb_jsonrpc_monitor_selection select;
-};
-
-/* A particular table being monitored. */
-struct ovsdb_jsonrpc_monitor_table {
-    const struct ovsdb_table *table;
-
-    /* This is the union (bitwise-OR) of the 'select' values in all of the
-     * members of 'columns' below. */
-    enum ovsdb_jsonrpc_monitor_selection select;
-
-    /* Columns being monitored. */
-    struct ovsdb_jsonrpc_monitor_column *columns;
-    size_t n_columns;
-};
-
-/* A collection of tables being monitored. */
+/* Jsonrpc front end monitor. */
 struct ovsdb_jsonrpc_monitor {
-    struct ovsdb_replica replica;
     struct ovsdb_jsonrpc_session *session;
+    struct ovsdb *db;
     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
-
     struct json *monitor_id;
-    struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
+    struct ovsdb_monitor *dbmon;
+    uint64_t unflushed;         /* The first transaction that has not been
+                                       flushed to the jsonrpc remote client. */
+    enum ovsdb_monitor_version version;
 };
 
-static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
-
-struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
-    struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
-static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
-static struct json *ovsdb_jsonrpc_monitor_get_initial(
-    const struct ovsdb_jsonrpc_monitor *);
-
-static bool
-parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
-{
-    const struct json *json;
-
-    json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
-    return json ? json_boolean(json) : default_value;
-}
-
-struct ovsdb_jsonrpc_monitor *
+static struct ovsdb_jsonrpc_monitor *
 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
                            const struct json *monitor_id)
 {
@@ -778,40 +1081,23 @@ ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
     return NULL;
 }
 
-static void
-ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
-                                 const struct ovsdb_column *column,
-                                 enum ovsdb_jsonrpc_monitor_selection select,
-                                 size_t *allocated_columns)
-{
-    struct ovsdb_jsonrpc_monitor_column *c;
-
-    if (mt->n_columns >= *allocated_columns) {
-        mt->columns = x2nrealloc(mt->columns, allocated_columns,
-                                 sizeof *mt->columns);
-    }
-
-    c = &mt->columns[mt->n_columns++];
-    c->column = column;
-    c->select = select;
-}
-
-static int
-compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
+static bool
+parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
 {
-    const struct ovsdb_jsonrpc_monitor_column *a = a_;
-    const struct ovsdb_jsonrpc_monitor_column *b = b_;
+    const struct json *json;
 
-    return a->column < b->column ? -1 : a->column > b->column;
+    json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
+    return json ? json_boolean(json) : default_value;
 }
 
-static struct ovsdb_error * WARN_UNUSED_RESULT
-ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
+static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
+ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_monitor *dbmon,
+                                    const struct ovsdb_table *table,
                                     const struct json *monitor_request,
                                     size_t *allocated_columns)
 {
-    const struct ovsdb_table_schema *ts = mt->table->schema;
-    enum ovsdb_jsonrpc_monitor_selection select;
+    const struct ovsdb_table_schema *ts = table->schema;
+    enum ovsdb_monitor_selection select;
     const struct json *columns, *select_json;
     struct ovsdb_parser parser;
     struct ovsdb_error *error;
@@ -847,8 +1133,8 @@ ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
     } else {
         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
     }
-    mt->select |= select;
 
+    ovsdb_monitor_table_add_select(dbmon, table, select);
     if (columns) {
         size_t i;
 
@@ -867,13 +1153,13 @@ ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
             }
 
             s = columns->u.array.elems[i]->u.string;
-            column = shash_find_data(&mt->table->schema->columns, s);
+            column = shash_find_data(&table->schema->columns, s);
             if (!column) {
                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
                                           "column name", s);
             }
-            ovsdb_jsonrpc_add_monitor_column(mt, column, select,
-                                             allocated_columns);
+            ovsdb_monitor_add_column(dbmon, table, column, select,
+                                     allocated_columns);
         }
     } else {
         struct shash_node *node;
@@ -881,8 +1167,8 @@ ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
         SHASH_FOR_EACH (node, &ts->columns) {
             const struct ovsdb_column *column = node->data;
             if (column->index != OVSDB_COL_UUID) {
-                ovsdb_jsonrpc_add_monitor_column(mt, column, select,
-                                                 allocated_columns);
+                ovsdb_monitor_add_column(dbmon, table, column, select,
+                                         allocated_columns);
             }
         }
     }
@@ -890,11 +1176,14 @@ ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
     return NULL;
 }
 
-static struct json *
-ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
-                             struct json *params)
+static struct jsonrpc_msg *
+ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
+                             struct json *params,
+                             enum ovsdb_monitor_version version,
+                             const struct json *request_id)
 {
     struct ovsdb_jsonrpc_monitor *m = NULL;
+    struct ovsdb_monitor *dbmon = NULL;
     struct json *monitor_id, *monitor_requests;
     struct ovsdb_error *error = NULL;
     struct shash_node *node;
@@ -918,30 +1207,29 @@ ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
     }
 
     m = xzalloc(sizeof *m);
-    ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
-    ovsdb_add_replica(s->remote->server->db, &m->replica);
     m->session = s;
+    m->db = db;
+    m->dbmon = ovsdb_monitor_create(db, m);
+    m->unflushed = 0;
+    m->version = version;
     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
     m->monitor_id = json_clone(monitor_id);
-    shash_init(&m->tables);
 
     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
         const struct ovsdb_table *table;
-        struct ovsdb_jsonrpc_monitor_table *mt;
+        const char *column_name;
         size_t allocated_columns;
         const struct json *mr_value;
         size_t i;
 
-        table = ovsdb_get_table(s->remote->server->db, node->name);
+        table = ovsdb_get_table(m->db, node->name);
         if (!table) {
             error = ovsdb_syntax_error(NULL, NULL,
                                        "no table named %s", node->name);
             goto error;
         }
 
-        mt = xzalloc(sizeof *mt);
-        mt->table = table;
-        shash_add(&m->tables, table->schema->name, mt);
+        ovsdb_monitor_add_table(m->dbmon, table);
 
         /* Parse columns. */
         mr_value = node->data;
@@ -951,42 +1239,50 @@ ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
 
             for (i = 0; i < array->n; i++) {
                 error = ovsdb_jsonrpc_parse_monitor_request(
-                    mt, array->elems[i], &allocated_columns);
+                    m->dbmon, table, array->elems[i], &allocated_columns);
                 if (error) {
                     goto error;
                 }
             }
         } else {
             error = ovsdb_jsonrpc_parse_monitor_request(
-                mt, mr_value, &allocated_columns);
+                m->dbmon, table, mr_value, &allocated_columns);
             if (error) {
                 goto error;
             }
         }
 
-        /* Check for duplicate columns. */
-        qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
-              compare_ovsdb_jsonrpc_monitor_column);
-        for (i = 1; i < mt->n_columns; i++) {
-            if (mt->columns[i].column == mt->columns[i - 1].column) {
-                error = ovsdb_syntax_error(mr_value, NULL, "column %s "
-                                           "mentioned more than once",
-                                           mt->columns[i].column->name);
-                goto error;
-            }
+        column_name = ovsdb_monitor_table_check_duplicates(m->dbmon, table);
+
+        if (column_name) {
+            error = ovsdb_syntax_error(mr_value, NULL, "column %s "
+                                       "mentioned more than once",
+                                        column_name);
+            goto error;
         }
     }
 
-    return ovsdb_jsonrpc_monitor_get_initial(m);
+    dbmon = ovsdb_monitor_add(m->dbmon);
+    if (dbmon != m->dbmon) {
+        /* Found an exisiting dbmon, reuse the current one. */
+        ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
+        ovsdb_monitor_add_jsonrpc_monitor(dbmon, m);
+        m->dbmon = dbmon;
+    }
+
+    ovsdb_monitor_get_initial(m->dbmon);
+    json = ovsdb_jsonrpc_monitor_compose_update(m, true);
+    json = json ? json : json_object_create();
+    return jsonrpc_create_reply(json, request_id);
 
 error:
     if (m) {
-        ovsdb_remove_replica(s->remote->server->db, &m->replica);
+        ovsdb_jsonrpc_monitor_destroy(m);
     }
 
     json = ovsdb_error_to_json(error);
     ovsdb_error_destroy(error);
-    return json;
+    return jsonrpc_create_error(json, request_id);
 }
 
 static struct jsonrpc_msg *
@@ -1005,7 +1301,7 @@ ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
             return jsonrpc_create_error(json_string_create("unknown monitor"),
                                         request_id);
         } else {
-            ovsdb_remove_replica(s->remote->server->db, &m->replica);
+            ovsdb_jsonrpc_monitor_destroy(m);
             return jsonrpc_create_reply(json_object_create(), request_id);
         }
     }
@@ -1017,219 +1313,89 @@ ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
     struct ovsdb_jsonrpc_monitor *m, *next;
 
     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
-        ovsdb_remove_replica(s->remote->server->db, &m->replica);
+        ovsdb_jsonrpc_monitor_destroy(m);
     }
 }
 
-static struct ovsdb_jsonrpc_monitor *
-ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
-{
-    assert(replica->class == &ovsdb_jsonrpc_replica_class);
-    return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
-}
-
-struct ovsdb_jsonrpc_monitor_aux {
-    bool initial;               /* Sending initial contents of table? */
-    const struct ovsdb_jsonrpc_monitor *monitor;
-    struct json *json;          /* JSON for the whole transaction. */
-
-    /* Current table.  */
-    struct ovsdb_jsonrpc_monitor_table *mt;
-    struct json *table_json;    /* JSON for table's transaction. */
-};
-
-static bool
-any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
-                      const unsigned long int *changed)
+static struct json *
+ovsdb_jsonrpc_monitor_compose_update(struct ovsdb_jsonrpc_monitor *m,
+                                     bool initial)
 {
-    size_t i;
-
-    for (i = 0; i < mt->n_columns; i++) {
-        const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
-        unsigned int idx = c->column->index;
-
-        if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
-            return true;
-        }
+    if (!ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
+        return NULL;
     }
 
-    return false;
+    return ovsdb_monitor_get_update(m->dbmon, initial, &m->unflushed,
+                                    m->version);
 }
 
 static bool
-ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
-                                const struct ovsdb_row *new,
-                                const unsigned long int *changed,
-                                void *aux_)
+ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
 {
-    struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
-    const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
-    struct ovsdb_table *table = new ? new->table : old->table;
-    enum ovsdb_jsonrpc_monitor_selection type;
-    struct json *old_json, *new_json;
-    struct json *row_json;
-    char uuid[UUID_LEN + 1];
-    size_t i;
-
-    if (!aux->mt || table != aux->mt->table) {
-        aux->mt = shash_find_data(&m->tables, table->schema->name);
-        aux->table_json = NULL;
-        if (!aux->mt) {
-            /* We don't care about rows in this table at all.  Tell the caller
-             * to skip it.  */
-            return false;
-        }
-    }
-
-    type = (aux->initial ? OJMS_INITIAL
-            : !old ? OJMS_INSERT
-            : !new ? OJMS_DELETE
-            : OJMS_MODIFY);
-    if (!(aux->mt->select & type)) {
-        /* We don't care about this type of change (but do want to be called
-         * back for changes to other rows in the same table). */
-        return true;
-    }
-
-    if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
-        /* Nothing of interest changed. */
-        return true;
-    }
-
-    old_json = new_json = NULL;
-    if (type & (OJMS_DELETE | OJMS_MODIFY)) {
-        old_json = json_object_create();
-    }
-    if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
-        new_json = json_object_create();
-    }
-    for (i = 0; i < aux->mt->n_columns; i++) {
-        const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
-        const struct ovsdb_column *column = c->column;
-        unsigned int idx = c->column->index;
-
-        if (!(type & c->select)) {
-            /* We don't care about this type of change for this particular
-             * column (but we will care about it for some other column). */
-            continue;
-        }
+    struct ovsdb_jsonrpc_monitor *m;
 
-        if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
-            || type == OJMS_DELETE) {
-            json_object_put(old_json, column->name,
-                            ovsdb_datum_to_json(&old->fields[idx],
-                                                &column->type));
-        }
-        if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
-            json_object_put(new_json, column->name,
-                            ovsdb_datum_to_json(&new->fields[idx],
-                                                &column->type));
+    HMAP_FOR_EACH (m, node, &s->monitors) {
+        if (ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
+            return true;
         }
     }
 
-    /* Create JSON object for transaction overall. */
-    if (!aux->json) {
-        aux->json = json_object_create();
-    }
-
-    /* Create JSON object for transaction on this table. */
-    if (!aux->table_json) {
-        aux->table_json = json_object_create();
-        json_object_put(aux->json, aux->mt->table->schema->name,
-                        aux->table_json);
-    }
-
-    /* Create JSON object for transaction on this row. */
-    row_json = json_object_create();
-    if (old_json) {
-        json_object_put(row_json, "old", old_json);
-    }
-    if (new_json) {
-        json_object_put(row_json, "new", new_json);
-    }
-
-    /* Add JSON row to JSON table. */
-    snprintf(uuid, sizeof uuid,
-             UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
-    json_object_put(aux->table_json, uuid, row_json);
-
-    return true;
+    return false;
 }
 
-static void
-ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
-                               const struct ovsdb_jsonrpc_monitor *m,
-                               bool initial)
+void
+ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
 {
-    aux->initial = initial;
-    aux->monitor = m;
-    aux->json = NULL;
-    aux->mt = NULL;
-    aux->table_json = NULL;
+    json_destroy(m->monitor_id);
+    hmap_remove(&m->session->monitors, &m->node);
+    ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
+    free(m);
 }
 
-static struct ovsdb_error *
-ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
-                             const struct ovsdb_txn *txn,
-                             bool durable OVS_UNUSED)
+static struct jsonrpc_msg *
+ovsdb_jsonrpc_create_notify(const struct ovsdb_jsonrpc_monitor *m,
+                            struct json *params)
 {
-    struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
-    struct ovsdb_jsonrpc_monitor_aux aux;
-
-    ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
-    ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
-    if (aux.json) {
-        struct jsonrpc_msg *msg;
-        struct json *params;
-
-        params = json_array_create_2(json_clone(aux.monitor->monitor_id),
-                                     aux.json);
-        msg = jsonrpc_create_notify("update", params);
-        jsonrpc_session_send(aux.monitor->session->js, msg);
+    const char *method;
+
+    switch(m->version) {
+    case OVSDB_MONITOR_V1:
+        method = "update";
+        break;
+    case OVSDB_MONITOR_V2:
+        method = "update2";
+        break;
+    case OVSDB_MONITOR_VERSION_MAX:
+    default:
+        OVS_NOT_REACHED();
     }
 
-    return NULL;
+    return jsonrpc_create_notify(method, params);
 }
 
-static struct json *
-ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
+static void
+ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
 {
-    struct ovsdb_jsonrpc_monitor_aux aux;
-    struct shash_node *node;
+    struct ovsdb_jsonrpc_monitor *m;
 
-    ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
-    SHASH_FOR_EACH (node, &m->tables) {
-        struct ovsdb_jsonrpc_monitor_table *mt = node->data;
+    HMAP_FOR_EACH (m, node, &s->monitors) {
+        struct json *json;
 
-        if (mt->select & OJMS_INITIAL) {
-            struct ovsdb_row *row;
+        json = ovsdb_jsonrpc_monitor_compose_update(m, false);
+        if (json) {
+            struct jsonrpc_msg *msg;
+            struct json *params;
 
-            HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
-                ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
-            }
+            params = json_array_create_2(json_clone(m->monitor_id), json);
+            msg = ovsdb_jsonrpc_create_notify(m, params);
+            jsonrpc_session_send(s->js, msg);
         }
     }
-    return aux.json ? aux.json : json_object_create();
 }
 
-static void
-ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
+void
+ovsdb_jsonrpc_disable_monitor2(void)
 {
-    struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
-    struct shash_node *node;
-
-    json_destroy(m->monitor_id);
-    SHASH_FOR_EACH (node, &m->tables) {
-        struct ovsdb_jsonrpc_monitor_table *mt = node->data;
-        free(mt->columns);
-        free(mt);
-    }
-    shash_destroy(&m->tables);
-    hmap_remove(&m->session->monitors, &m->node);
-    free(m);
+    /* Once disabled, it is not possible to re-enable it. */
+    monitor2_enable__ = false;
 }
-
-static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
-    ovsdb_jsonrpc_monitor_commit,
-    ovsdb_jsonrpc_monitor_destroy
-};