Re: Question regarding Sync message and unnamed portal

Tatsuo Ishii <ishii@postgresql.org> writes:
>> The right thing to use if you're trying to interleave portal executions
>> like that is Flush, not Sync.  Sync mainly adds a protocol
>> resynchronization point --- it's needed in case portal execution fails
>> partway through.  (In which case you'll have lost both portals in the
>> transaction abort anyway.)

> Thanks for the suggestion. However, problem with using Flush is,
> backend never sends "Ready for Query" until Sync is sent. For frontend
> program "Ready for query" is important because 1) client knows session
> state, 2) "Ready for query" is a command boundary as stated in
> document.

[ shrug... ]  RFQ is an acknowledgement of a sync point.  It's useful
for clients that are too lazy to keep track of the protocol state in
great detail --- but if you're trying to interleave execution of two
portals, you need to keep track.
        regards, tom lane