Hi,
We,re running cassandra 1.0.3.
I've done some testing with 2 nodes (node A, node B), replication factor 2.
I take node A down, writing some data to node B and then take node A up.
Sometimes hints aren't delivered when node A comes up.
I've done some debugging in org.apache.cassandra.db.HintedHandOffManager
and sometimes node B ends up in a strange state in method
org.apache.cassandra.db.HintedHandOffManager.deliverHints(final
InetAddress to), where
org.apache.cassandra.db.HintedHandOffManager.queuedDeliveries already
has node A in it's Set and therefore no hints will ever be delivered to
node A.
The only reason for this that I can see is that in
org.apache.cassandra.db.HintedHandOffManager.deliverHintsToEndpoint(InetAddress
endpoint) the hintStore.isEmpty() check returns true and the endpoint
(node A) isn't removed from
org.apache.cassandra.db.HintedHandOffManager.queuedDeliveries. Then no
hints will ever be delivered again until node B is restarted.
During what conditions will hintStore.isEmpty() return true?
Shouldn't the hintStore.isEmpty() check be inside the try {} finally{}
clause, removing the endpoint from queuedDeliveries in the finally block?
public void deliverHints(final InetAddress to)
{
logger_.debug("deliverHints to {}", to);
*if (!queuedDeliveries.add(to))*
return;
.......
}
private void deliverHintsToEndpoint(InetAddress endpoint) throws
IOException, DigestMismatchException, InvalidRequestException,
TimeoutException,
{
ColumnFamilyStore hintStore =
Table.open(Table.SYSTEM_TABLE).getColumnFamilyStore(HINTS_CF);
* if (hintStore.isEmpty())*
return; // nothing to do, don't confuse users by logging a
no-op handoff
try
{
......
}
finally
{
*queuedDeliveries.remove(endpoint);*
}
}
Regards
/Fredrik
