Re: [HACKERS] PL/pgSQL and SPI

Jan Wieck wrote:
> 
>         ...  And  I've  added  two  silly
>         functions   SPI_push()   and   SPI_pop()   that    simply
>         increment/decrement   the   _SPI_curid   value.  This  is
>         required for calling ExecEvalExpr(), because there  could
>         be   functions   evaluated  that  use  SPI  themself  and
>         otherwise they could not connect to the SPI manager. They
>         are  dangerous  and  I'm  in  doubt if we should document              ^^^^^^^^^
No more than improper call of SPI_finish()...

>         them.
> 
>     2.  While doing the above I've encountered some  bad  details
>         of  the  SPI  manager and the executor. The Func and Oper
>         nodes point to a function cache, which is initially  NULL
>         and is not copied by copyNode().
> 
>         For every call of SPI_execp() to execute a prepared plan,
>         the whole plan is copied into the current memory context.
>         Since  this clears out the fcache, the executor has to do
>         several syscache lookups for every function  or  operator
>         hit during execution of the plan.
> 
>         Unfortunately  I  haven't  found  a  way yet to avoid it.
>         Anything I tried so  far  ended  in  coredumps  or  other
>         misbehaviour. Maybe someone else has an idea.

Could we fill most of FunctionCache while parsing query ?!
We can do this for 
   int         typlen;         /* length of the return type */   int         typbyval;       /* true if return type is
passby value */
 
...   Oid         foid;           /* oid of the function in pg_proc */   Oid         language;       /* oid of the
languagein pg_language */   int         nargs;          /* number of arguments */
 
   Oid        *argOidVect;     /* oids of all the arguments */
...   bool        istrusted;      /* trusted fn? */

and may be others too.

Vadim