Обсуждение: SPI_exec does not return!

Hi,

if I do a SELECT on a non-existing table, SPI_exec won't return.
I get, e. g. in pgaccess, an error message "<table> does not exist",
and my code below the function call is never reached.

So why return error codes for SPI_exec when you cannot evaluate them?

The background:

I need to distinguish different client connections within a trigger
function.
To do this, I create a temporary table within a "login" function.
My trigger must check for the existence of this function.
I cannot think of any other method, since there is no "connection id" or
something like that!

This would also be an application for checking the existance of a
temporary table,
as was asked for in another thread in this list before.

How can I check for the existence of a temporary table without getting
interuppted?????

Thanks,

Markus

Markus Wagner wrote:
> Hi,
>
> if I do a SELECT on a non-existing table, SPI_exec won't return.
> I get, e. g. in pgaccess, an error message "<table> does not exist",
> and my code below the function call is never reached.
   Right,  the  SPI_exec()  call  in  turn  calls the PostgreSQL   parser and that raises an elog(ERROR) which
longjmp()'s back   into  the  backends  main  loop  waiting  for the next client   query.
 

>
> So why return error codes for SPI_exec when you cannot evaluate them?
   What do you want here? No error,  just  an  empty  result  of   unspecified  format?   If the parser cannot
determine(due to   nonexistance of a table) which datatype the  columns  of  the   result  set  at least should have,
whatelse could he do than   trowing an ERROR?
 

>
> The background:
>
> I need to distinguish different client connections within a trigger
> function.
> To do this, I create a temporary table within a "login" function.
> My trigger must check for the existence of this function.
> I cannot think of any other method, since there is no "connection id" or
> something like that!
   Unfortunately PL/pgSQL doesn't have global variables.  PL/Tcl   can  have.   If you cannot code a part of the login
mechanism  in PL/Tcl, setting a global variable and  returning  that  in   another  PL/Tcl  function, you could create
atemp table with   the same name in every connection and fill the  connection-ID   into that.
 


Jan

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