As far as I can see isc_sweep_concurrent_instance is returned to the client which started sweep. Where is is handled in a case when sweep started automatically? IMO it should be silently ignored.

As I can see, allowSweepThread() will not allow us to run auto sweep if we have concurrent instances, but I added a check for isc_sweep_concurrent_instance anyway, just in case.

OK. I reviewed the code once again. Initial problem can be fixed much simpler:

diff --git a/src/jrd/tra.cpp b/src/jrd/tra.cpp
index 3acd848976..f289c0d923 100644
--- a/src/jrd/tra.cpp
+++ b/src/jrd/tra.cpp
@@ -1848,7 +1848,6 @@ void TRA_sweep(thread_db* tdbb)

        if (!dbb->allowSweepRun(tdbb))
        {
-               dbb->clearSweepFlags(tdbb);
                return;
        }

But suggested patch contains new feature - user is notified what happened, without it sweep silently finishes in a moment. But I do not understand - why no diags in cases of RO database and explicitly set ATT_no_cleanup? If you want to add diags for sweep startup failure all cases should better be taken into an account.

If you want to add diags for sweep startup failure all cases should better be taken into an account.

Yeah, I agree. I will add more error messages.

But suggested patch contains new feature - user is notified what happened, without it sweep silently finishes in a moment.

How it works for auto-sweep ?

But suggested patch contains new feature - user is notified what happened, without it sweep silently finishes in a moment.

How it works for auto-sweep ?

See
#8320 (comment)