Re: [Re] wrong protocol sequence?

John DeSoi wrote:

> On Sep 22, 2005, at 10:11 AM, Андрей wrote:
>
>> I'm sending such messages to server in native postgresql
>> protocol: 'Parse' -> 'Describe' -> 'Sync' (get: 'Parse Complete' and
>> 'Ready For Query' messages back).
>> But when the sequence became: 'Parse' -> 'Sync' (get: 'Parse
>> Complete' and 'Ready For Query' messages back), little pause,
>> 'Describe' -> 'Sync' - server is crashing (error = memory can't be
>> 'read')!
>>
>> My query is as simple as possible 'select * from table_name'.
>> What am I doing wrong?
>
>
> I think I recall having some problems around this also. But I don't
> think there is any reason to need Parse -> Sync anyway. If you just
> want to prepare, use Parse -> Describe -> Sync. For executing, Parse
> (if not already parsed) -> Bind -> Describe -> Execute -> Sync.
>
> John DeSoi, Ph.D.
> http://pgedit.com/
> Power Tools for PostgreSQL

The reason is to get parameters description (if there are any in
query) before binding them to the backend. For example 'select * from
table_name where column_name = $1'. I would like to get required type of
parameter $1 to bind later. But I can't be sure at prepare time, that
I'll need such description in future.

Thanks for your answer,
Andrei