[ovs-dev] another possible cause of incremental update problems

Ben Pfaff blp at ovn.org
Sat Aug 20 15:32:50 UTC 2016


There are additional possible causes of incremental update problems that
I haven't previously seen mentioned here.  If you look at the functions
that implement incremental update, they tend to start with:

    if (!ctx->ovnsb_idl_txn) {
        return NULL;
    }

or similar.  This makes sense, because there is no point in composing an
update if it can't be committed.  However, because the main loop call
ovsdb_idl_txn_clear() on every iteration, that means that any updates
from this iteration will be lost.

Also, transactions can fail.  In that case, the transaction needs to be
recomposed and retried.  ovn-controller currently doesn't have any
mechanism for that.



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