Re: Protocol question - fastpath & parameter status 'S'

On Sep 5, 2011, at 7:05 AM, Radosław Smogura wrote:

> Hello,
>
> During testing of (forked) driver we had seen following strange behaviour. JDBC driver mainly invokes Fastpath to obtain LOBs, because of unscientific privileges I get
> 1. Some bytes
> 2. 'E' (error about priviliges)
> 3. (sic!) 'S' application_name (driver throws exception)
> Now I analyse buffer byte after byte
> 4. 'Z', 00 00 00 05 69 108 (last number may be trash)
>
> It's looks like without 3 everything should be OK, so... I have question if this is intended and undocumented behaviour, or some async trashes came in, because docs says nothing about 'S'. I found this only one app server, but I don't think it makes some "background" async calls.
>

'S' is the Sync message.

http://www.postgresql.org/docs/current/static/protocol-message-formats.html

See this section to understand the role of the Sync message:

http://www.postgresql.org/docs/current/static/protocol-flow.html#PROTOCOL-FLOW-EXT-QUERY

John DeSoi, Ph.D.