ovsdb: Add support for online schema conversion.

With this change, "ovsdb-client convert" can be used to convert a database
from one schema to another without taking the database offline.

This can be useful to minimize downtime for a database during a software
upgrade.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/ovsdb/monitor.c b/ovsdb/monitor.c
index 8c3053722..dd06e265e 100644
--- a/ovsdb/monitor.c
+++ b/ovsdb/monitor.c
@@ -1612,7 +1612,7 @@ ovsdb_monitors_remove(struct ovsdb *db)
         /* Delete all front-end monitors.  Removing the last front-end monitor
          * will also destroy the corresponding ovsdb_monitor. */
         LIST_FOR_EACH_SAFE (jm, next_jm, node, &m->jsonrpc_monitors) {
-            ovsdb_jsonrpc_monitor_destroy(jm->jsonrpc_monitor);
+            ovsdb_jsonrpc_monitor_destroy(jm->jsonrpc_monitor, false);
         }
     }
 }
@@ -1629,3 +1629,19 @@ ovsdb_monitor_get_memory_usage(struct simap *usage)
         simap_increase(usage, "json-caches", hmap_count(&dbmon->json_cache));
     }
 }
+
+void
+ovsdb_monitor_prereplace_db(struct ovsdb *db)
+{
+    struct ovsdb_monitor *m, *next_m;
+
+    LIST_FOR_EACH_SAFE (m, next_m, list_node, &db->monitors) {
+        struct jsonrpc_monitor_node *jm, *next_jm;
+
+        /* Delete all front-end monitors.  Removing the last front-end monitor
+         * will also destroy the corresponding ovsdb_monitor. */
+        LIST_FOR_EACH_SAFE (jm, next_jm, node, &m->jsonrpc_monitors) {
+            ovsdb_jsonrpc_monitor_destroy(jm->jsonrpc_monitor, true);
+        }
+    }
+}