Dropping events possible reasons?

[hectorvp]

Can anyone enlist possible reasons when UF may drop events?

There may be many situations, but some known reasons came from practical experiences...

[richgalloway · Accepted solution]

If you suspect a UF is dropping events or you're concerned about the possibility of it then turn on Indexer Acknowledgement.  The acks will tell the UF when events are indexed.  The UF will retransmit events that are not acknowledged.

[hectorvp]

Thanks @richgalloway , 

UF generally pushes logs using  TCP connection, so it gives reliability transportation layer, adding indexer ACK would add reliability at application layer right?

Since you haven't mentioned any such scenario, I'm considering there are no such known issues where events are dropped.

[richgalloway]

Yes, there are scenarios where events can be dropped, but Indexer Ack prevents them.