The output statement schedules an event
to be sent to downstream streams,
and also to be entered into the associated store.
For example:
output [k = 10; | d = 20;];
If a Flex operator is sending output to a stateless store,
all attempts to
output a non-insert are rejected.
Note:
You can use multiple output statements to process an event;
the outputs are collected as a transaction block.
Similarly,
if a Flex operator receives a transaction block,
the entire transaction block is processed
and all output is collected into another transaction block.
This means that downstream streams,
and the record data stored within the stream,
are not changed until the entire event
(single event or transaction block) is processed.