[ovs-dev,v4,2/4] ovn-ic: Introduce incremental processing.

diff --git a/ic/automake.mk b/ic/automake.mk
index 8e71bc334..a69b1030d 100644
--- a/ic/automake.mk
+++ b/ic/automake.mk
@@ -1,6 +1,11 @@ 
 # ovn-ic
 bin_PROGRAMS += ic/ovn-ic
-ic_ovn_ic_SOURCES = ic/ovn-ic.c
+ic_ovn_ic_SOURCES = ic/ovn-ic.c \
+	ic/ovn-ic.h \
+	ic/en-ic.c \
+	ic/en-ic.h \
+	ic/inc-proc-ic.c \
+	ic/inc-proc-ic.h
 ic_ovn_ic_LDADD = \
 	lib/libovn.la \
 	$(OVSDB_LIBDIR)/libovsdb.la \
diff --git a/ic/en-ic.c b/ic/en-ic.c
new file mode 100644
index 000000000..2db9d3b84
--- /dev/null
+++ b/ic/en-ic.c
@@ -0,0 +1,50 @@ 
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+
+#include <config.h>
+
+#include <getopt.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "en-ic.h"
+#include "lib/inc-proc-eng.h"
+#include "lib/stopwatch-names.h"
+#include "ovn-ic.h"
+#include "openvswitch/vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(en_ic);
+
+enum engine_node_state
+en_ic_run(struct engine_node *node OVS_UNUSED, void *data OVS_UNUSED)
+{
+    const struct engine_context *eng_ctx = engine_get_context();
+    struct ic_context *ctx = eng_ctx->client_ctx;
+
+    ovn_db_run(ctx);
+
+    return EN_UPDATED;
+}
+
+void *
+en_ic_init(struct engine_node *node OVS_UNUSED,
+            struct engine_arg *arg OVS_UNUSED)
+{
+    return NULL;
+}
+
+void
+en_ic_cleanup(void *data OVS_UNUSED)
+{
+}
diff --git a/ic/en-ic.h b/ic/en-ic.h
new file mode 100644
index 000000000..a4b75bb0e
--- /dev/null
+++ b/ic/en-ic.h
@@ -0,0 +1,18 @@ 
+#ifndef EN_IC_H
+#define EN_IC_H 1
+
+#include <config.h>
+
+#include <getopt.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "lib/inc-proc-eng.h"
+
+enum engine_node_state en_ic_run(struct engine_node *node OVS_UNUSED,
+                                 void *data OVS_UNUSED);
+void *en_ic_init(struct engine_node *node OVS_UNUSED,
+                 struct engine_arg *arg);
+void en_ic_cleanup(void *data);
+
+#endif /* EN_IC_H */
diff --git a/ic/inc-proc-ic.c b/ic/inc-proc-ic.c
new file mode 100644
index 000000000..ba9fdeb9e
--- /dev/null
+++ b/ic/inc-proc-ic.c
@@ -0,0 +1,269 @@ 
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+
+#include <getopt.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "lib/inc-proc-eng.h"
+#include "lib/ovn-nb-idl.h"
+#include "lib/ovn-sb-idl.h"
+#include "lib/ovn-ic-nb-idl.h"
+#include "lib/ovn-ic-sb-idl.h"
+#include "openvswitch/poll-loop.h"
+#include "openvswitch/vlog.h"
+#include "inc-proc-ic.h"
+#include "en-ic.h"
+#include "unixctl.h"
+#include "util.h"
+
+VLOG_DEFINE_THIS_MODULE(inc_proc_ic);
+
+#define NB_NODES \
+    NB_NODE(nb_global, "nb_global") \
+    NB_NODE(logical_router_static_route, "logical_router_static_route") \
+    NB_NODE(logical_router, "logical_router") \
+    NB_NODE(logical_router_port, "logical_router_port") \
+    NB_NODE(logical_switch, "logical_switch") \
+    NB_NODE(logical_switch_port, "logical_switch_port") \
+    NB_NODE(load_balancer, "load_balancer") \
+    NB_NODE(load_balancer_group, "load_balancer_group")
+
+    enum nb_engine_node {
+#define NB_NODE(NAME, NAME_STR) NB_##NAME,
+    NB_NODES
+#undef NB_NODE
+    };
+
+/* Define engine node functions for nodes that represent NB tables
+ *
+ * en_nb_<TABLE_NAME>_run()
+ * en_nb_<TABLE_NAME>_init()
+ * en_nb_<TABLE_NAME>_cleanup()
+ */
+#define NB_NODE(NAME, NAME_STR) ENGINE_FUNC_NB(NAME);
+    NB_NODES
+#undef NB_NODE
+
+#define SB_NODES \
+    SB_NODE(sb_global, "sb_global") \
+    SB_NODE(chassis, "chassis") \
+    SB_NODE(encap, "encap") \
+    SB_NODE(datapath_binding, "datapath_binding") \
+    SB_NODE(port_binding, "port_binding") \
+    SB_NODE(service_monitor, "service_monitor")
+
+    enum sb_engine_node {
+#define SB_NODE(NAME, NAME_STR) SB_##NAME,
+    SB_NODES
+#undef SB_NODE
+};
+
+/* Define engine node functions for nodes that represent SB tables
+ *
+ * en_sb_<TABLE_NAME>_run()
+ * en_sb_<TABLE_NAME>_init()
+ * en_sb_<TABLE_NAME>_cleanup()
+ */
+#define SB_NODE(NAME, NAME_STR) ENGINE_FUNC_SB(NAME);
+    SB_NODES
+#undef SB_NODE
+
+#define ICNB_NODES \
+    ICNB_NODE(ic_nb_global, "ic_nb_global") \
+    ICNB_NODE(transit_switch, "transit_switch") \
+    ICNB_NODE(transit_router, "transit_router") \
+    ICNB_NODE(transit_router_port, "transit_router_port")
+
+    enum icnb_engine_node {
+#define ICNB_NODE(NAME, NAME_STR) ICNB_##NAME,
+    ICNB_NODES
+#undef ICNB_NODE
+    };
+
+/* Define engine node functions for nodes that represent ICNB tables
+ *
+ * en_icnb_<TABLE_NAME>_run()
+ * en_icnb_<TABLE_NAME>_init()
+ * en_icnb_<TABLE_NAME>_cleanup()
+ */
+#define ICNB_NODE(NAME, NAME_STR) ENGINE_FUNC_ICNB(NAME);
+    ICNB_NODES
+#undef ICNB_NODE
+
+#define ICSB_NODES \
+    ICSB_NODE(ic_sb_global, "ic_sb_global") \
+    ICSB_NODE(availability_zone, "availability_zone") \
+    ICSB_NODE(service_monitor, "service_monitor") \
+    ICSB_NODE(route, "route") \
+    ICSB_NODE(datapath_binding, "datapath_binding") \
+    ICSB_NODE(encap, "encap") \
+    ICSB_NODE(gateway, "gateway") \
+    ICSB_NODE(port_binding, "port_binding")
+
+    enum icsb_engine_node {
+#define ICSB_NODE(NAME, NAME_STR) ICSB_##NAME,
+    ICSB_NODES
+#undef ICSB_NODE
+    };
+
+/* Define engine node functions for nodes that represent ICSB tables
+ *
+ * en_icsb_<TABLE_NAME>_run()
+ * en_icsb_<TABLE_NAME>_init()
+ * en_icsb_<TABLE_NAME>_cleanup()
+ */
+#define ICSB_NODE(NAME, NAME_STR) ENGINE_FUNC_ICSB(NAME);
+    ICSB_NODES
+#undef ICSB_NODE
+
+/* Define engine nodes for NB, SB, ICNB and ICSB tables
+ *
+ * struct engine_node en_nb_<TABLE_NAME>
+ * struct engine_node en_sb_<TABLE_NAME>
+ * struct engine_node en_icnb_<TABLE_NAME>
+ * struct engine_node en_icsb_<TABLE_NAME>
+ *
+ * Define nodes as static to avoid sparse errors.
+ */
+#define NB_NODE(NAME, NAME_STR) static ENGINE_NODE_NB(NAME);
+    NB_NODES
+#undef NB_NODE
+
+#define SB_NODE(NAME, NAME_STR) static ENGINE_NODE_SB(NAME);
+    SB_NODES
+#undef SB_NODE
+
+#define ICNB_NODE(NAME, NAME_STR) static ENGINE_NODE_ICNB(NAME);
+    ICNB_NODES
+#undef ICNB_NODE
+
+#define ICSB_NODE(NAME, NAME_STR) static ENGINE_NODE_ICSB(NAME);
+    ICSB_NODES
+#undef ICSB_NODE
+
+/* Define engine nodes for other nodes. They should be defined as static to
+ * avoid sparse errors. */
+static ENGINE_NODE(ic);
+
+void inc_proc_ic_init(struct ovsdb_idl_loop *nb,
+                      struct ovsdb_idl_loop *sb,
+                      struct ovsdb_idl_loop *icnb,
+                      struct ovsdb_idl_loop *icsb)
+{
+    /* Define relationships between nodes where first argument is dependent
+     * on the second argument */
+    engine_add_input(&en_ic, &en_nb_nb_global, NULL);
+    engine_add_input(&en_ic, &en_nb_logical_router_static_route, NULL);
+    engine_add_input(&en_ic, &en_nb_logical_router, NULL);
+    engine_add_input(&en_ic, &en_nb_logical_router_port, NULL);
+    engine_add_input(&en_ic, &en_nb_logical_switch, NULL);
+    engine_add_input(&en_ic, &en_nb_logical_switch_port, NULL);
+    engine_add_input(&en_ic, &en_nb_load_balancer, NULL);
+    engine_add_input(&en_ic, &en_nb_load_balancer_group, NULL);
+
+    engine_add_input(&en_ic, &en_sb_sb_global, NULL);
+    engine_add_input(&en_ic, &en_sb_chassis, NULL);
+    engine_add_input(&en_ic, &en_sb_encap, NULL);
+    engine_add_input(&en_ic, &en_sb_datapath_binding, NULL);
+    engine_add_input(&en_ic, &en_sb_port_binding, NULL);
+    engine_add_input(&en_ic, &en_sb_service_monitor, NULL);
+
+    engine_add_input(&en_ic, &en_icnb_ic_nb_global, NULL);
+    engine_add_input(&en_ic, &en_icnb_transit_switch, NULL);
+    engine_add_input(&en_ic, &en_icnb_transit_router, NULL);
+    engine_add_input(&en_ic, &en_icnb_transit_router_port, NULL);
+
+    engine_add_input(&en_ic, &en_icsb_encap, NULL);
+    engine_add_input(&en_ic, &en_icsb_service_monitor, NULL);
+    engine_add_input(&en_ic, &en_icsb_ic_sb_global, NULL);
+    engine_add_input(&en_ic, &en_icsb_port_binding, NULL);
+    engine_add_input(&en_ic, &en_icsb_availability_zone, NULL);
+    engine_add_input(&en_ic, &en_icsb_gateway, NULL);
+    engine_add_input(&en_ic, &en_icsb_route, NULL);
+    engine_add_input(&en_ic, &en_icsb_datapath_binding, NULL);
+
+    struct engine_arg engine_arg = {
+        .nb_idl = nb->idl,
+        .sb_idl = sb->idl,
+        .icnb_idl = icnb->idl,
+        .icsb_idl = icsb->idl,
+    };
+
+    engine_init(&en_ic, &engine_arg);
+}
+
+/* Returns true if the incremental processing ended up updating nodes. */
+bool
+inc_proc_ic_run(struct ic_context *ctx,
+                struct ic_engine_context *ic_eng_ctx)
+{
+    ovs_assert(ctx->ovnnb_txn && ctx->ovnsb_txn &&
+               ctx->ovninb_txn && ctx->ovnisb_txn);
+
+    int64_t start = time_msec();
+    engine_init_run();
+
+    struct engine_context eng_ctx = {
+        .client_ctx = ctx,
+    };
+
+    engine_set_context(&eng_ctx);
+    engine_run(true);
+
+    if (!engine_has_run()) {
+        if (engine_need_run()) {
+            VLOG_DBG("engine did not run, force recompute next time.");
+            engine_set_force_recompute_immediate();
+        } else {
+            VLOG_DBG("engine did not run, and it was not needed");
+        }
+    } else if (engine_canceled()) {
+        VLOG_DBG("engine was canceled, force recompute next time.");
+        engine_set_force_recompute_immediate();
+    } else {
+        engine_clear_force_recompute();
+    }
+
+    int64_t now = time_msec();
+    /* Postpone the next run by length of current run with maximum capped
+     * by "northd-backoff-interval-ms" interval. */
+    ic_eng_ctx->next_run_ms = now + MIN(now - start, ic_eng_ctx->backoff_ms);
+
+    return engine_has_updated();
+}
+
+void
+inc_proc_ic_cleanup(void)
+{
+    engine_cleanup();
+    engine_set_context(NULL);
+}
+
+bool
+inc_proc_ic_can_run(struct ic_engine_context *ctx)
+{
+    if (engine_get_force_recompute() || time_msec() >= ctx->next_run_ms ||
+        ctx->nb_idl_duration_ms >= IDL_LOOP_MAX_DURATION_MS ||
+        ctx->sb_idl_duration_ms >= IDL_LOOP_MAX_DURATION_MS ||
+        ctx->inb_idl_duration_ms >= IDL_LOOP_MAX_DURATION_MS ||
+        ctx->isb_idl_duration_ms >= IDL_LOOP_MAX_DURATION_MS) {
+        return true;
+    }
+
+    poll_timer_wait_until(ctx->next_run_ms);
+    return false;
+}
diff --git a/ic/inc-proc-ic.h b/ic/inc-proc-ic.h
new file mode 100644
index 000000000..9af147fb3
--- /dev/null
+++ b/ic/inc-proc-ic.h
@@ -0,0 +1,48 @@ 
+#ifndef INC_PROC_IC_H
+#define INC_PROC_IC_H 1
+
+#include <config.h>
+
+#include "ovn-ic.h"
+#include "ovsdb-idl.h"
+#include "lib/inc-proc-eng.h"
+
+struct ic_engine_context {
+    int64_t next_run_ms;
+    uint64_t nb_idl_duration_ms;
+    uint64_t sb_idl_duration_ms;
+    uint64_t inb_idl_duration_ms;
+    uint64_t isb_idl_duration_ms;
+    uint32_t backoff_ms;
+};
+
+void inc_proc_ic_init(struct ovsdb_idl_loop *nb,
+                      struct ovsdb_idl_loop *sb,
+                      struct ovsdb_idl_loop *icnb,
+                      struct ovsdb_idl_loop *icsb);
+
+bool inc_proc_ic_run(struct ic_context *ctx,
+                     struct ic_engine_context *ic_eng_ctx);
+
+void inc_proc_ic_cleanup(void);
+bool inc_proc_ic_can_run(struct ic_engine_context *ctx);
+
+static inline void
+inc_proc_ic_force_recompute(void)
+{
+    engine_set_force_recompute();
+}
+
+static inline void
+inc_proc_ic_force_recompute_immediate(void)
+{
+    engine_set_force_recompute_immediate();
+}
+
+static inline bool
+inc_proc_ic_get_force_recompute(void)
+{
+    return engine_get_force_recompute();
+}
+
+#endif /* INC_PROC_IC */
diff --git a/ic/ovn-ic.c b/ic/ovn-ic.c
index 0ef82f3a3..0e8c0953d 100644
--- a/ic/ovn-ic.c
+++ b/ic/ovn-ic.c
@@ -46,6 +46,8 @@ 
 #include "uuid.h"
 #include "openvswitch/vlog.h"
 #include "vec.h"
+#include "inc-proc-ic.h"
+#include "ovn-ic.h"
 
 VLOG_DEFINE_THIS_MODULE(ovn_ic);
 
@@ -55,45 +57,6 @@  static unixctl_cb_func ovn_ic_resume;
 static unixctl_cb_func ovn_ic_is_paused;
 static unixctl_cb_func ovn_ic_status;
 
-struct ic_context {
-    struct ovsdb_idl *ovnnb_idl;
-    struct ovsdb_idl *ovnsb_idl;
-    struct ovsdb_idl *ovninb_idl;
-    struct ovsdb_idl *ovnisb_idl;
-    struct ovsdb_idl_txn *ovnnb_txn;
-    struct ovsdb_idl_txn *ovnsb_txn;
-    struct ovsdb_idl_txn *ovninb_txn;
-    struct ovsdb_idl_txn *ovnisb_txn;
-    const struct icsbrec_availability_zone *runned_az;
-    struct ovsdb_idl_index *nbrec_ls_by_name;
-    struct ovsdb_idl_index *nbrec_lr_by_name;
-    struct ovsdb_idl_index *nbrec_lrp_by_name;
-    struct ovsdb_idl_index *nbrec_port_by_name;
-    struct ovsdb_idl_index *sbrec_chassis_by_name;
-    struct ovsdb_idl_index *sbrec_port_binding_by_name;
-    struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type;
-    struct ovsdb_idl_index *sbrec_service_monitor_by_ic_learned;
-    struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type_logical_port;
-    struct ovsdb_idl_index *icnbrec_transit_switch_by_name;
-    struct ovsdb_idl_index *icsbrec_port_binding_by_az;
-    struct ovsdb_idl_index *icsbrec_port_binding_by_ts;
-    struct ovsdb_idl_index *icsbrec_port_binding_by_ts_az;
-    struct ovsdb_idl_index *icsbrec_route_by_az;
-    struct ovsdb_idl_index *icsbrec_route_by_ts;
-    struct ovsdb_idl_index *icsbrec_route_by_ts_az;
-    struct ovsdb_idl_index *icsbrec_service_monitor_by_source_az;
-    struct ovsdb_idl_index *icsbrec_service_monitor_by_target_az;
-    struct ovsdb_idl_index *icsbrec_service_monitor_by_target_az_logical_port;
-};
-
-struct ic_state {
-    bool had_lock;
-    bool paused;
-};
-
-enum ic_datapath_type { IC_SWITCH, IC_ROUTER, IC_DATAPATH_MAX };
-enum ic_port_binding_type { IC_SWITCH_PORT, IC_ROUTER_PORT, IC_PORT_MAX };
-
 static const char *ovnnb_db;
 static const char *ovnsb_db;
 static const char *ovn_ic_nb_db;
@@ -3091,7 +3054,7 @@  update_sequence_numbers(struct ic_context *ctx,
     }
 }
 
-static void
+void
 ovn_db_run(struct ic_context *ctx)
 {
     struct hmap dp_tnlids = HMAP_INITIALIZER(&dp_tnlids);
@@ -3311,172 +3274,183 @@  main(int argc, char *argv[])
     /* ovn-ic-nb db. */
     struct ovsdb_idl_loop ovninb_idl_loop = OVSDB_IDL_LOOP_INITIALIZER(
         ovsdb_idl_create(ovn_ic_nb_db, &icnbrec_idl_class, true, true));
+    ovsdb_idl_track_add_all(ovninb_idl_loop.idl);
 
     /* ovn-ic-sb db. */
     struct ovsdb_idl_loop ovnisb_idl_loop = OVSDB_IDL_LOOP_INITIALIZER(
         ovsdb_idl_create(ovn_ic_sb_db, &icsbrec_idl_class, true, true));
+    ovsdb_idl_track_add_all(ovnisb_idl_loop.idl);
 
     /* ovn-nb db. */
     struct ovsdb_idl_loop ovnnb_idl_loop = OVSDB_IDL_LOOP_INITIALIZER(
         ovsdb_idl_create(ovnnb_db, &nbrec_idl_class, false, true));
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_nb_global);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl, &nbrec_nb_global_col_name);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl, &nbrec_nb_global_col_options);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_nb_global_col_name);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_nb_global_col_options);
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl,
                         &nbrec_table_logical_router_static_route);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_route_table);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_ip_prefix);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_nexthop);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_external_ids);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_options);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_static_route_col_policy);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_route_table);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_ip_prefix);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_nexthop);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_external_ids);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_options);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                    &nbrec_logical_router_static_route_col_policy);
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_logical_router);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_name);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_static_routes);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_ports);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_options);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_external_ids);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_enabled);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_load_balancer);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_col_load_balancer_group);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_name);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_static_routes);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_ports);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_options);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_external_ids);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_enabled);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_load_balancer);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_col_load_balancer_group);
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_logical_router_port);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_port_col_mac);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_port_col_name);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_port_col_networks);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_port_col_external_ids);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_router_port_col_options);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_port_col_mac);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_port_col_name);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_port_col_networks);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_port_col_external_ids);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_router_port_col_options);
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_logical_switch);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_col_name);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_col_ports);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_col_other_config);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_col_external_ids);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_col_name);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_col_ports);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_col_other_config);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_col_external_ids);
 
     ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_logical_switch_port);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_name);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_addresses);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_options);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_type);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_up);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_addresses);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_enabled);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_logical_switch_port_col_external_ids);
-
-    ovsdb_idl_add_table(ovnnb_idl_loop.idl,
-                        &nbrec_table_load_balancer);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_load_balancer_col_vips);
-
-    ovsdb_idl_add_table(ovnnb_idl_loop.idl,
-                        &nbrec_table_load_balancer_group);
-    ovsdb_idl_add_column(ovnnb_idl_loop.idl,
-                         &nbrec_load_balancer_group_col_load_balancer);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_name);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_addresses);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_options);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_type);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_up);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_addresses);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_enabled);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_logical_switch_port_col_external_ids);
+
+    ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_load_balancer);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_load_balancer_col_vips);
+
+    ovsdb_idl_add_table(ovnnb_idl_loop.idl, &nbrec_table_load_balancer_group);
+    ovsdb_idl_track_add_column(ovnnb_idl_loop.idl,
+                               &nbrec_load_balancer_group_col_load_balancer);
 
     /* ovn-sb db. */
     struct ovsdb_idl_loop ovnsb_idl_loop = OVSDB_IDL_LOOP_INITIALIZER(
         ovsdb_idl_create(ovnsb_db, &sbrec_idl_class, false, true));
 
     ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_sb_global);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_sb_global_col_options);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_sb_global_col_options);
 
     ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_chassis);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_encaps);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_name);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_hostname);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_other_config);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_chassis_col_encaps);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_chassis_col_name);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_chassis_col_hostname);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_chassis_col_other_config);
 
     ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_encap);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_encap_col_chassis_name);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_encap_col_type);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_encap_col_ip);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_encap_col_options);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_encap_col_chassis_name);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_encap_col_type);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_encap_col_ip);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_encap_col_options);
 
     ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_datapath_binding);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_datapath_binding_col_type);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_datapath_binding_col_external_ids);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_datapath_binding_col_nb_uuid);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_datapath_binding_col_type);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_datapath_binding_col_external_ids);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_datapath_binding_col_nb_uuid);
 
     ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_port_binding);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_datapath);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_mac);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_options);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_logical_port);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_external_ids);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_chassis);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_port_binding_col_up);
-
-    ovsdb_idl_add_table(ovnsb_idl_loop.idl,
-                        &sbrec_table_service_monitor);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_chassis_name);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_external_ids);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_type);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_ip);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_logical_port);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_port);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_protocol);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_src_ip);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_src_mac);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_remote);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_ic_learned);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_status);
-    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
-                         &sbrec_service_monitor_col_options);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_datapath);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_mac);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_options);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_logical_port);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_external_ids);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_chassis);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_port_binding_col_up);
+
+    ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_service_monitor);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_chassis_name);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_external_ids);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_type);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_ip);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_logical_port);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_port);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_protocol);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_src_ip);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_src_mac);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_remote);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_ic_learned);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_status);
+    ovsdb_idl_track_add_column(ovnsb_idl_loop.idl,
+                               &sbrec_service_monitor_col_options);
 
     /* Create IDL indexes */
     struct ovsdb_idl_index *nbrec_ls_by_name
@@ -3497,7 +3471,7 @@  main(int argc, char *argv[])
         = ovsdb_idl_index_create1(ovnsb_idl_loop.idl,
                                   &sbrec_chassis_col_name);
 
-   struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type
+    struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type
         = ovsdb_idl_index_create1(ovnsb_idl_loop.idl,
                                   &sbrec_service_monitor_col_remote);
 
@@ -3562,10 +3536,22 @@  main(int argc, char *argv[])
     unixctl_command_register("ic-sb-connection-status", "", 0, 0,
                              ovn_conn_show, ovnisb_idl_loop.idl);
 
+    /* Initialize incremental processing engine for ovn-northd */
+    inc_proc_ic_init(&ovnnb_idl_loop, &ovnsb_idl_loop,
+                     &ovninb_idl_loop, &ovnisb_idl_loop);
+
+    unsigned int ovnnb_cond_seqno = UINT_MAX;
+    unsigned int ovnsb_cond_seqno = UINT_MAX;
+    unsigned int ovninb_cond_seqno = UINT_MAX;
+    unsigned int ovnisb_cond_seqno = UINT_MAX;
+
     /* Main loop. */
+    struct ic_engine_context  eng_ctx = {0};
+
     exiting = false;
     state.had_lock = false;
     state.paused = false;
+
     while (!exiting) {
         update_ssl_config();
         update_idl_probe_interval(ovnsb_idl_loop.idl, ovnnb_idl_loop.idl,
@@ -3579,6 +3565,7 @@  main(int argc, char *argv[])
             simap_destroy(&usage);
         }
 
+        bool clear_idl_track = true;
         if (!state.paused) {
             if (!ovsdb_idl_has_lock(ovnsb_idl_loop.idl) &&
                 !ovsdb_idl_is_lock_contended(ovnsb_idl_loop.idl))
@@ -3590,15 +3577,67 @@  main(int argc, char *argv[])
                 ovsdb_idl_set_lock(ovnsb_idl_loop.idl, "ovn_ic");
             }
 
+            struct ovsdb_idl_txn *ovnnb_txn =
+                run_idl_loop(&ovnnb_idl_loop, "OVN_Northbound",
+                             &eng_ctx.nb_idl_duration_ms);
+            unsigned int new_ovnnb_cond_seqno =
+                        ovsdb_idl_get_condition_seqno(ovnnb_idl_loop.idl);
+            if (new_ovnnb_cond_seqno != ovnnb_cond_seqno) {
+                if (!new_ovnnb_cond_seqno) {
+                    VLOG_INFO("OVN NB IDL reconnected, force recompute.");
+                    inc_proc_ic_force_recompute();
+                }
+                ovnnb_cond_seqno = new_ovnnb_cond_seqno;
+            }
+
+            struct ovsdb_idl_txn *ovnsb_txn =
+                run_idl_loop(&ovnsb_idl_loop, "OVN_Southbound",
+                             &eng_ctx.sb_idl_duration_ms);
+            unsigned int new_ovnsb_cond_seqno =
+                        ovsdb_idl_get_condition_seqno(ovnsb_idl_loop.idl);
+            if (new_ovnsb_cond_seqno != ovnsb_cond_seqno) {
+                if (!new_ovnsb_cond_seqno) {
+                    VLOG_INFO("OVN SB IDL reconnected, force recompute.");
+                    inc_proc_ic_force_recompute();
+                }
+                ovnsb_cond_seqno = new_ovnsb_cond_seqno;
+            }
+
+            struct ovsdb_idl_txn *ovninb_txn =
+                run_idl_loop(&ovninb_idl_loop, "OVN_IC_Northbound",
+                             &eng_ctx.inb_idl_duration_ms);
+            unsigned int new_ovninb_cond_seqno =
+                        ovsdb_idl_get_condition_seqno(ovninb_idl_loop.idl);
+            if (new_ovninb_cond_seqno != ovninb_cond_seqno) {
+                if (!new_ovninb_cond_seqno) {
+                    VLOG_INFO("OVN INB IDL reconnected, force recompute.");
+                    inc_proc_ic_force_recompute();
+                }
+                ovninb_cond_seqno = new_ovninb_cond_seqno;
+            }
+
+            struct ovsdb_idl_txn *ovnisb_txn =
+                run_idl_loop(&ovnisb_idl_loop, "OVN_IC_Southbound",
+                             &eng_ctx.isb_idl_duration_ms);
+            unsigned int new_ovnisb_cond_seqno =
+                        ovsdb_idl_get_condition_seqno(ovnisb_idl_loop.idl);
+            if (new_ovnisb_cond_seqno != ovnisb_cond_seqno) {
+                if (!new_ovnisb_cond_seqno) {
+                    VLOG_INFO("OVN ISB IDL reconnected, force recompute.");
+                    inc_proc_ic_force_recompute();
+                }
+                ovnisb_cond_seqno = new_ovnisb_cond_seqno;
+            }
+
             struct ic_context ctx = {
                 .ovnnb_idl = ovnnb_idl_loop.idl,
-                .ovnnb_txn = ovsdb_idl_loop_run(&ovnnb_idl_loop),
+                .ovnnb_txn = ovnnb_txn,
                 .ovnsb_idl = ovnsb_idl_loop.idl,
-                .ovnsb_txn = ovsdb_idl_loop_run(&ovnsb_idl_loop),
+                .ovnsb_txn = ovnsb_txn,
                 .ovninb_idl = ovninb_idl_loop.idl,
-                .ovninb_txn = ovsdb_idl_loop_run(&ovninb_idl_loop),
+                .ovninb_txn = ovninb_txn,
                 .ovnisb_idl = ovnisb_idl_loop.idl,
-                .ovnisb_txn = ovsdb_idl_loop_run(&ovnisb_idl_loop),
+                .ovnisb_txn = ovnisb_txn,
                 .nbrec_ls_by_name = nbrec_ls_by_name,
                 .nbrec_lr_by_name = nbrec_lr_by_name,
                 .nbrec_lrp_by_name = nbrec_lrp_by_name,
@@ -3627,44 +3666,75 @@  main(int argc, char *argv[])
                     icsbrec_service_monitor_by_target_az_logical_port,
             };
 
-            if (!state.had_lock && ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) {
+            if (!state.had_lock && ovsdb_idl_has_lock(ctx.ovnsb_idl)) {
                 VLOG_INFO("ovn-ic lock acquired. "
-                        "This ovn-ic instance is now active.");
+                            "This ovn-ic instance is now active.");
                 state.had_lock = true;
             } else if (state.had_lock &&
-                       !ovsdb_idl_has_lock(ovnsb_idl_loop.idl)) {
+                       !ovsdb_idl_has_lock(ctx.ovnsb_idl)) {
                 VLOG_INFO("ovn-ic lock lost. "
-                        "This ovn-ic instance is now on standby.");
+                            "This ovn-ic instance is now on standby.");
                 state.had_lock = false;
             }
 
-            if (ovsdb_idl_has_lock(ovnsb_idl_loop.idl) &&
+            if (ovsdb_idl_has_lock(ctx.ovnsb_idl) &&
                 ovsdb_idl_has_ever_connected(ctx.ovnnb_idl) &&
                 ovsdb_idl_has_ever_connected(ctx.ovnsb_idl) &&
                 ovsdb_idl_has_ever_connected(ctx.ovninb_idl) &&
                 ovsdb_idl_has_ever_connected(ctx.ovnisb_idl)) {
-                const struct icsbrec_availability_zone *az = az_run(&ctx);
-                VLOG_DBG("Availability zone: %s", az ? az->name :
-                                               "not created yet.");
-                if (az) {
-                    ovn_db_run(&ctx);
-                    update_sequence_numbers(&ctx, &ovnisb_idl_loop);
+                if (ctx.ovnnb_txn && ctx.ovnsb_txn && ctx.ovninb_txn &&
+                    ctx.ovnisb_txn && inc_proc_ic_can_run(&eng_ctx)) {
+                    ctx.runned_az = az_run(&ctx);
+                    VLOG_DBG("Availability zone: %s", ctx.runned_az ?
+                             ctx.runned_az->name : "not created yet.");
+                    if (ctx.runned_az) {
+                        (void) inc_proc_ic_run(&ctx, &eng_ctx);
+                        update_sequence_numbers(&ctx, &ovnisb_idl_loop);
+                    }
+                } else if (!inc_proc_ic_get_force_recompute()) {
+                    clear_idl_track = false;
+                }
+                /* If there are any errors, we force a full recompute in order
+                 * to ensure we handle all changes. */
+                if (!ovsdb_idl_loop_commit_and_wait(&ovnnb_idl_loop)) {
+                    VLOG_INFO("OVNNB commit failed, "
+                                "force recompute next time.");
+                    inc_proc_ic_force_recompute_immediate();
                 }
 
-            }
+                if (!ovsdb_idl_loop_commit_and_wait(&ovnsb_idl_loop)) {
+                    VLOG_INFO("OVNSB commit failed, "
+                                "force recompute next time.");
+                    inc_proc_ic_force_recompute_immediate();
+                }
+
+                if (!ovsdb_idl_loop_commit_and_wait(&ovninb_idl_loop)) {
+                    VLOG_INFO("OVNINB commit failed, "
+                                "force recompute next time.");
+                    inc_proc_ic_force_recompute_immediate();
+                }
 
-            int rc1 = ovsdb_idl_loop_commit_and_wait(&ovnnb_idl_loop);
-            int rc2 = ovsdb_idl_loop_commit_and_wait(&ovnsb_idl_loop);
-            int rc3 = ovsdb_idl_loop_commit_and_wait(&ovninb_idl_loop);
-            int rc4 = ovsdb_idl_loop_commit_and_wait(&ovnisb_idl_loop);
-            if (!rc1 || !rc2 || !rc3 || !rc4) {
-                VLOG_DBG(" a transaction failed in: %s %s %s %s",
-                         !rc1 ? "nb" : "", !rc2 ? "sb" : "",
-                         !rc3 ? "ic_nb" : "", !rc4 ? "ic_sb" : "");
-                /* A transaction failed. Wake up immediately to give
-                 * opportunity to send the proper transaction
-                 */
-                poll_immediate_wake();
+                if (!ovsdb_idl_loop_commit_and_wait(&ovnisb_idl_loop)) {
+                    VLOG_INFO("OVNISB commit failed, "
+                                "force recompute next time.");
+                    inc_proc_ic_force_recompute_immediate();
+                }
+            } else {
+                /* Make sure we send any pending requests, e.g., lock. */
+                int rc1 = ovsdb_idl_loop_commit_and_wait(&ovnnb_idl_loop);
+                int rc2 = ovsdb_idl_loop_commit_and_wait(&ovnsb_idl_loop);
+                int rc3 = ovsdb_idl_loop_commit_and_wait(&ovninb_idl_loop);
+                int rc4 = ovsdb_idl_loop_commit_and_wait(&ovnisb_idl_loop);
+                if (!rc1 || !rc2 || !rc3 || !rc4) {
+                    VLOG_DBG(" a transaction failed in: %s %s %s %s",
+                            !rc1 ? "nb" : "", !rc2 ? "sb" : "",
+                            !rc3 ? "ic_nb" : "", !rc4 ? "ic_sb" : "");
+                    /* A transaction failed. Wake up immediately to give
+                    * opportunity to send the proper transaction
+                    */
+                }
+                /* Force a full recompute next time we become active. */
+                inc_proc_ic_force_recompute();
             }
         } else {
             /* ovn-ic is paused
@@ -3690,6 +3760,16 @@  main(int argc, char *argv[])
             ovsdb_idl_wait(ovnsb_idl_loop.idl);
             ovsdb_idl_wait(ovninb_idl_loop.idl);
             ovsdb_idl_wait(ovnisb_idl_loop.idl);
+
+            /* Force a full recompute next time we become active. */
+            inc_proc_ic_force_recompute_immediate();
+        }
+
+        if (clear_idl_track) {
+            ovsdb_idl_track_clear(ovnnb_idl_loop.idl);
+            ovsdb_idl_track_clear(ovnsb_idl_loop.idl);
+            ovsdb_idl_track_clear(ovninb_idl_loop.idl);
+            ovsdb_idl_track_clear(ovnisb_idl_loop.idl);
         }
 
         unixctl_server_run(unixctl);
@@ -3704,6 +3784,7 @@  main(int argc, char *argv[])
             exiting = true;
         }
     }
+    inc_proc_ic_cleanup();
 
     unixctl_server_destroy(unixctl);
     ovsdb_idl_loop_destroy(&ovnnb_idl_loop);
diff --git a/ic/ovn-ic.h b/ic/ovn-ic.h
new file mode 100644
index 000000000..e8d7a970f
--- /dev/null
+++ b/ic/ovn-ic.h
@@ -0,0 +1,61 @@ 
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef OVN_IC_H
+#define OVN_IC_H 1
+
+#include "ovsdb-idl.h"
+#include "unixctl.h"
+
+struct ic_context {
+    struct ovsdb_idl *ovnnb_idl;
+    struct ovsdb_idl *ovnsb_idl;
+    struct ovsdb_idl *ovninb_idl;
+    struct ovsdb_idl *ovnisb_idl;
+    struct ovsdb_idl_txn *ovnnb_txn;
+    struct ovsdb_idl_txn *ovnsb_txn;
+    struct ovsdb_idl_txn *ovninb_txn;
+    struct ovsdb_idl_txn *ovnisb_txn;
+    const struct icsbrec_availability_zone *runned_az;
+    struct ovsdb_idl_index *nbrec_ls_by_name;
+    struct ovsdb_idl_index *nbrec_lr_by_name;
+    struct ovsdb_idl_index *nbrec_lrp_by_name;
+    struct ovsdb_idl_index *nbrec_port_by_name;
+    struct ovsdb_idl_index *sbrec_chassis_by_name;
+    struct ovsdb_idl_index *sbrec_port_binding_by_name;
+    struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type;
+    struct ovsdb_idl_index *sbrec_service_monitor_by_ic_learned;
+    struct ovsdb_idl_index *sbrec_service_monitor_by_remote_type_logical_port;
+    struct ovsdb_idl_index *icnbrec_transit_switch_by_name;
+    struct ovsdb_idl_index *icsbrec_port_binding_by_az;
+    struct ovsdb_idl_index *icsbrec_port_binding_by_ts;
+    struct ovsdb_idl_index *icsbrec_port_binding_by_ts_az;
+    struct ovsdb_idl_index *icsbrec_route_by_az;
+    struct ovsdb_idl_index *icsbrec_route_by_ts;
+    struct ovsdb_idl_index *icsbrec_route_by_ts_az;
+    struct ovsdb_idl_index *icsbrec_service_monitor_by_source_az;
+    struct ovsdb_idl_index *icsbrec_service_monitor_by_target_az;
+    struct ovsdb_idl_index *icsbrec_service_monitor_by_target_az_logical_port;
+};
+
+struct ic_state {
+    bool had_lock;
+    bool paused;
+};
+
+enum ic_datapath_type { IC_SWITCH, IC_ROUTER, IC_DATAPATH_MAX };
+enum ic_port_binding_type { IC_SWITCH_PORT, IC_ROUTER_PORT, IC_PORT_MAX };
+
+void ovn_db_run(struct ic_context *ctx);
+
+#endif /* OVN_IC_H */
diff --git a/lib/inc-proc-eng.h b/lib/inc-proc-eng.h
index 02eeb46fe..1cb2466b2 100644
--- a/lib/inc-proc-eng.h
+++ b/lib/inc-proc-eng.h
@@ -158,6 +158,8 @@  struct engine_context {
     struct ovsdb_idl_txn *ovnsb_idl_txn;
     struct ovsdb_idl_txn *ovnnb_idl_txn;
     struct ovsdb_idl_txn *ovnbr_idl_txn;
+    struct ovsdb_idl_txn *ovnisb_idl_txn;
+    struct ovsdb_idl_txn *ovninb_idl_txn;
 
     void *client_ctx;
 };
@@ -167,6 +169,8 @@  struct engine_arg {
     struct ovsdb_idl *sb_idl;
     struct ovsdb_idl *nb_idl;
     struct ovsdb_idl *ovnbr_idl;
+    struct ovsdb_idl *icsb_idl;
+    struct ovsdb_idl *icnb_idl;
     struct ovsdb_idl *ovs_idl;
 };
 
@@ -547,6 +551,16 @@  en_##DB_NAME##_##TBL_NAME##_compute_failure_info(struct engine_node *node)  \
 #define ENGINE_FUNC_BR(TBL_NAME) \
     ENGINE_FUNC_OVSDB(ovnbr, TBL_NAME)
 
+/* Macro to define member functions of an engine node which represents
+ * a table of OVN ISB DB */
+#define ENGINE_FUNC_ICSB(TBL_NAME) \
+    ENGINE_FUNC_OVSDB(icsb, TBL_NAME)
+
+/* Macro to define member functions of an engine node which represents
+ * a table of OVN INB DB */
+#define ENGINE_FUNC_ICNB(TBL_NAME) \
+    ENGINE_FUNC_OVSDB(icnb, TBL_NAME)
+
 /* Macro to define member functions of an engine node which represents
  * a table of open_vswitch DB */
 #define ENGINE_FUNC_OVS(TBL_NAME) \
@@ -569,6 +583,13 @@  en_##DB_NAME##_##TBL_NAME##_compute_failure_info(struct engine_node *node)  \
 /* Macro to define an engine node which represents a table of OVN BR DB */
 #define ENGINE_NODE_BR(TBL_NAME) \
     ENGINE_NODE_OVSDB(ovnbr, "BR", TBL_NAME, #TBL_NAME);
+/* Macro to define an engine node which represents a table of OVN ISB DB */
+#define ENGINE_NODE_ICSB(TBL_NAME) \
+    ENGINE_NODE_OVSDB(icsb, "ICSB", TBL_NAME, #TBL_NAME);
+
+/* Macro to define an engine node which represents a table of OVN INB DB */
+#define ENGINE_NODE_ICNB(TBL_NAME) \
+    ENGINE_NODE_OVSDB(icnb, "ICNB", TBL_NAME, #TBL_NAME);
 
 /* Macro to define an engine node which represents a table of open_vswitch
  * DB */