[ovs-discuss] [ovn] : ovn-northd not updating the south db when some new flows added in the code and restarted.

[Numan Siddique]

Hi,

I am seeing an issue with ovn-northd where in it is not updating the south db when I applied the "ovn: support ARP response for known IPs"
patch from Han Zhou add restarted the ovn-northd.

I didn't see the flows related to ARP getting reflected in the south db. It only got reflected when I updated the north db from neutron like creating a new port or restarting
the ovn-northd again.

By putting some prints, I could see that ovsdb_idl_txn_commit(ctx.ovnsb_txn) is returning TXN_ERROR after which it is blocked in poll_block().
until some update happens in north db.

The issue is not seen all the time. But only when ovsdb_idl_txn_commit returns TXN_ERROR.
 
The below code is fixing the issue. Wanted to get the comments from the reviewers if it is the right fix or
the problem lies some where else. Also not sure if there are any side effects because of the below fix.

---
 ovn/northd/ovn-northd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index 8fe0c2c..1c3821f 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -1990,7 +1990,8 @@ main(int argc, char *argv[])
         }
 
         if (ovnnb_seqno == ovsdb_idl_get_seqno(ovnnb_idl) &&
-                ovn_seqno == ovsdb_idl_get_seqno(ovnsb_idl)) {
+                ovn_seqno == ovsdb_idl_get_seqno(ovnsb_idl)
+                && !ovnnb_changes_pending) {
             ovsdb_idl_wait(ovnnb_idl);
             ovsdb_idl_wait(ovnsb_idl);
             if (ctx.ovnnb_txn) {
-- 





Thanks
Numan