Обсуждение: Postgres error.....

i wrote this simple script that exports a large object from database to a
file using the same database that contains a table  which matches the
objOid's to their names.  The script will work sometimes but sometimes it
doesn't.   Any one have any ideas...??? here is the script and the error.


proc export_file_lo { large_object_name filename {db "lo_db"} {host
"localhost"}
 {port "5432"} } {

     global lo_continue
     set conn [pg_connect $db -host $host -port $port]

     set lo_continue "false"

     pg_select $conn "SELECT * from match where name=
    \'$large_object_name\'" result {set objOid [process_result result]}

     if {$lo_continue == "true"} {

          pg_lo_export $conn $objOid $filename
     } else {
          puts "No object associated with name \"$large_object_name\" found."
          pg_disconnect $conn
          return 0
     }

     pg_disconnect $conn
     return 1


}

proc process_result {arrName} {
global lo_continue
upvar $arrName result

     set lo_continue "true"
     set objOid $result(objoid)

     return $objOid
}



Output:

    NOTICE:  SIAssignBackendId: discarding tag 2147483553
    Connection to database failed
    FATAL 1:  Backend cache invalidation initialization failed




thanks,tim

(1) PQftype() returns a value of type "Oid", but I haven't been able to
find a list of what those values might be. I noticed in the header files a
value of zero is considered invalid, but that's it. The docs I've found
don't tell me anything other than it an integer code representing the
type. What are the possible values?

(2) I noticed there are some C++ classes in /usr/include/libpq++ which
look similar to code I'm writing for my own education and use. Is there
any documentation which deals with these classes? (I've not seen any thus
far.)

(3) The third paramter to PQsetdb() is pgoptions. I've not found any
description of what these options might be. Where can I find a list of the
options?


Bruce Tong
Systems Programmer
Electronic Vision / FITNE

mailto: zztong@laxmi.ev.net
http://www.ev.net/fitne

On Fri, 5 Jun 1998, Bruce Tong wrote:

> (1) PQftype() returns a value of type "Oid", but I haven't been able to
> find a list of what those values might be. I noticed in the header files a
> value of zero is considered invalid, but that's it. The docs I've found
> don't tell me anything other than it an integer code representing the
> type. What are the possible values?

select oid,* from pg_type where oid = <type_oid>

where <type_oid> is between 16 and 32

>
> (2) I noticed there are some C++ classes in /usr/include/libpq++ which
> look similar to code I'm writing for my own education and use. Is there
> any documentation which deals with these classes? (I've not seen any thus
> far.)
>

Neither did I.

> (3) The third paramter to PQsetdb() is pgoptions. I've not found any
> description of what these options might be. Where can I find a list of the
> options?
>
>

The source says this is for setting backend options for this connection.

man postgres

to see the backend options.


Hope this helps..

    Marin


          -= Why do we need gates in a world without fences? =-

On Sat, 6 Jun 1998, Marin D wrote:

>
> >
> > (2) I noticed there are some C++ classes in /usr/include/libpq++ which
> > look similar to code I'm writing for my own education and use. Is there
> > any documentation which deals with these classes? (I've not seen any thus
> > far.)
> >
>
> Neither did I.
>

Silly to correct myself but there is a nice man page

man libpq++


Best regards

    Marin


          -= Why do we need gates in a world without fences? =-

> > (1) PQftype() returns a value of type "Oid", but I haven't been able to
> > find a list of what those values might be. I noticed in the header files a
> > value of zero is considered invalid, but that's it. The docs I've found
> > don't tell me anything other than it an integer code representing the
> > type. What are the possible values?
>
> select oid,* from pg_type where oid = <type_oid>
>
> where <type_oid> is between 16 and 32

Thats interesting. How in the world did you ever know to look there?

> > (3) The third paramter to PQsetdb() is pgoptions. I've not found any
> > description of what these options might be. Where can I find a list of the
> > options?
>
> The source says this is for setting backend options for this connection.
>
> man postgres
>
> to see the backend options.

Ahhh, I see. Boy I feel dumb for not having made that connection.


Bruce Tong
Systems Programmer
Electronic Vision / FITNE

mailto: zztong@laxmi.ev.net
http://www.ev.net/fitne

> > > (2) I noticed there are some C++ classes in /usr/include/libpq++ which
> > > look similar to code I'm writing for my own education and use. Is there
> > > any documentation which deals with these classes? (I've not seen any thus
> > > far.)
> >
> > Neither did I.
>
> Silly to correct myself but there is a nice man page
>
> man libpq++

So there is. I'm kicking myself now since I had found the libpq man page.
Ahh, I see. They've put the developer stuff in another RPM, so none of
this was showing up in the list of files belonging to the postgresql
package. This will give me some more things to look at.

Thanks a bunch.


Bruce Tong
Systems Programmer
Electronic Vision / FITNE

mailto: zztong@laxmi.ev.net
http://www.ev.net/fitne