Re: better support of out parameters in plperl - Mailing list pgsql-patches

Based on this analysis, and problems with differing regression results
on different platforms, this attached patch has been reverted.

---------------------------------------------------------------------------

Andrew Dunstan wrote:
>
>
> I wrote:
> > Pavel Stehule wrote:
> >> Hello,
> >>
> >> I send two small patches. First does conversion from perl to
> >> postgresql array in OUT parameters. Second patch allow hash form
> >> output from procedures with one OUT argument.
> >>
> >
> > I will try to review these in the next 2 weeks unless someone beats me
> > to it.
> >
> >
>
> I have reviewed this lightly, as committed by Bruce, and have some
> concerns. Unfortunately, the deathof my main workstation has cost me
> much of the time I intended to use for a more thorough review, so there
> may well be more issues than are outlined here.
>
> First, it is completely undocumented.
>
> Second, this comment is at best confusing:
>
>   /* if value is ref on array do to pg string array conversion */
>
>
> Third, it appears to assume that we will have names for all OUT params. But names are optional, as I understand it.
Arguably,we should be treating the returns positionally, and thus return an arrayref when there are OYT params, not a
hashref,and ignore the names - after all, all perl function args are nameless, in fact, even if you use a naming
conventionto refer to them. 
>
> Fourth, I don't understand the change: "allow hash form output from procedures with one OUT argument." That seems
verynon-orthogonal, and I can't see any good reason for it. 
>
> Lastly, if you look at the expected output as committed,it appears to have been prepared without being actually
examined,for example: 
>
>
> CREATE OR REPLACE FUNCTION test05(OUT a varchar) AS $$
>          return {a=>'ahoj'};
>        $$ LANGUAGE plperl;
> SELECT '05' AS i,a FROM test05();
>   i  |        a
>  ----+-----------------
>   05 | HASH(0x8558f9c)
>  (1 row)
>
>
> what???
>
> And now that I look I see every buildfarm box broken on PLCheck. That's no surprise at all.
>
>
> The conversation regarding these features appears only to have started on July 28th, which was probably much too late
givensome of the issues. Unless we can solve these issues very fast I would be inclined to say this should be tabled
for8.3. I think this is a fairly good illustration of the danger of springing a feature, largely undiscussed, on the
communityjust about freeze time. 
>
> cheers
>
> andrew
>
>
>
>
>

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: src/pl/plperl/plperl.c
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plperl/plperl.c,v
retrieving revision 1.115
retrieving revision 1.116
diff -c -r1.115 -r1.116
*** src/pl/plperl/plperl.c    12 Aug 2006 04:16:45 -0000    1.115
--- src/pl/plperl/plperl.c    13 Aug 2006 02:37:11 -0000    1.116
***************
*** 1,7 ****
  /**********************************************************************
   * plperl.c - perl as a procedural language for PostgreSQL
   *
!  *      $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.115 2006/08/12 04:16:45 momjian Exp $
   *
   **********************************************************************/

--- 1,7 ----
  /**********************************************************************
   * plperl.c - perl as a procedural language for PostgreSQL
   *
!  *      $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.116 2006/08/13 02:37:11 momjian Exp $
   *
   **********************************************************************/

***************
*** 52,57 ****
--- 52,58 ----
      FmgrInfo    result_in_func; /* I/O function and arg for result type */
      Oid            result_typioparam;
      int            nargs;
+     int         num_out_args;   /* number of out arguments */
      FmgrInfo    arg_out_func[FUNC_MAX_ARGS];
      bool        arg_is_rowtype[FUNC_MAX_ARGS];
      SV           *reference;
***************
*** 115,120 ****
--- 116,124 ----
  static void plperl_init_shared_libs(pTHX);
  static HV  *plperl_spi_execute_fetch_result(SPITupleTable *, int, int);

+ static SV  *plperl_convert_to_pg_array(SV *src);
+ static SV *plperl_transform_result(plperl_proc_desc *prodesc, SV *result);
+
  /*
   * This routine is a crock, and so is everyplace that calls it.  The problem
   * is that the cached form of plperl functions/queries is allocated permanently
***************
*** 404,410 ****
                      (errcode(ERRCODE_UNDEFINED_COLUMN),
                       errmsg("Perl hash contains nonexistent column \"%s\"",
                              key)));
!         if (SvOK(val) && SvTYPE(val) != SVt_NULL)
              values[attn - 1] = SvPV(val, PL_na);
      }
      hv_iterinit(perlhash);
--- 408,419 ----
                      (errcode(ERRCODE_UNDEFINED_COLUMN),
                       errmsg("Perl hash contains nonexistent column \"%s\"",
                              key)));
!
!         /* if value is ref on array do to pg string array conversion */
!         if (SvTYPE(val) == SVt_RV &&
!             SvTYPE(SvRV(val)) == SVt_PVAV)
!             values[attn - 1] = SvPV(plperl_convert_to_pg_array(val), PL_na);
!         else if (SvOK(val) && SvTYPE(val) != SVt_NULL)
              values[attn - 1] = SvPV(val, PL_na);
      }
      hv_iterinit(perlhash);
***************
*** 681,692 ****
      HeapTuple    tuple;
      Form_pg_proc proc;
      char        functyptype;
-     int            numargs;
-     Oid           *argtypes;
-     char      **argnames;
-     char       *argmodes;
      bool        istrigger = false;
-     int            i;

      /* Get the new function's pg_proc entry */
      tuple = SearchSysCache(PROCOID,
--- 690,696 ----
***************
*** 714,731 ****
                              format_type_be(proc->prorettype))));
      }

-     /* Disallow pseudotypes in arguments (either IN or OUT) */
-     numargs = get_func_arg_info(tuple,
-                                 &argtypes, &argnames, &argmodes);
-     for (i = 0; i < numargs; i++)
-     {
-         if (get_typtype(argtypes[i]) == 'p')
-             ereport(ERROR,
-                     (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                      errmsg("plperl functions cannot take type %s",
-                             format_type_be(argtypes[i]))));
-     }
-
      ReleaseSysCache(tuple);

      /* Postpone body checks if !check_function_bodies */
--- 718,723 ----
***************
*** 1128,1133 ****
--- 1120,1127 ----
          /* Return a perl string converted to a Datum */
          char       *val;

+         perlret = plperl_transform_result(prodesc, perlret);
+
          if (prodesc->fn_retisarray && SvROK(perlret) &&
              SvTYPE(SvRV(perlret)) == SVt_PVAV)
          {
***************
*** 1256,1262 ****
      char        internal_proname[64];
      int            proname_len;
      plperl_proc_desc *prodesc = NULL;
-     int            i;
      SV          **svp;

      /* We'll need the pg_proc tuple in any case... */
--- 1250,1255 ----
***************
*** 1319,1324 ****
--- 1312,1323 ----
          Datum        prosrcdatum;
          bool        isnull;
          char       *proc_source;
+         int            i;
+         int            numargs;
+         Oid           *argtypes;
+         char      **argnames;
+         char       *argmodes;
+

          /************************************************************
           * Allocate a new procedure description block
***************
*** 1337,1342 ****
--- 1336,1360 ----
          prodesc->fn_readonly =
              (procStruct->provolatile != PROVOLATILE_VOLATILE);

+
+         /* Disallow pseudotypes in arguments (either IN or OUT) */
+         /* Count number of out arguments */
+         numargs = get_func_arg_info(procTup,
+                                     &argtypes, &argnames, &argmodes);
+         for (i = 0; i < numargs; i++)
+         {
+             if (get_typtype(argtypes[i]) == 'p')
+                 ereport(ERROR,
+                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                          errmsg("plperl functions cannot take type %s",
+                                 format_type_be(argtypes[i]))));
+
+             if (argmodes && argmodes[i] == PROARGMODE_OUT)
+                 prodesc->num_out_args++;
+
+         }
+
+
          /************************************************************
           * Lookup the pg_language tuple by Oid
           ************************************************************/
***************
*** 1676,1681 ****
--- 1694,1701 ----
      fcinfo = current_call_data->fcinfo;
      rsi = (ReturnSetInfo *) fcinfo->resultinfo;

+     sv = plperl_transform_result(prodesc, sv);
+
      if (!prodesc->fn_retisset)
          ereport(ERROR,
                  (errcode(ERRCODE_SYNTAX_ERROR),
***************
*** 1753,1759 ****

          if (SvOK(sv) && SvTYPE(sv) != SVt_NULL)
          {
!             char       *val = SvPV(sv, PL_na);

              ret = InputFunctionCall(&prodesc->result_in_func, val,
                                      prodesc->result_typioparam, -1);
--- 1773,1788 ----

          if (SvOK(sv) && SvTYPE(sv) != SVt_NULL)
          {
!             char       *val;
!             SV         *array_ret;
!
!             if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PVAV )
!             {
!                 array_ret = plperl_convert_to_pg_array(sv);
!                 sv = array_ret;
!             }
!
!             val = SvPV(sv, PL_na);

              ret = InputFunctionCall(&prodesc->result_in_func, val,
                                      prodesc->result_typioparam, -1);
***************
*** 2368,2370 ****
--- 2397,2442 ----

      SPI_freeplan( plan);
  }
+
+ /*
+  * If plerl result is hash and fce result is scalar, it's hash form of
+  * out argument. Then, transform it to scalar
+  */
+
+ static SV *
+ plperl_transform_result(plperl_proc_desc *prodesc, SV *result)
+ {
+     bool        exactly_one_field = false;
+     HV         *hvr;
+     SV           *val;
+     char       *key;
+     I32            klen;
+
+
+     if (prodesc->num_out_args == 1 && SvOK(result)
+         && SvTYPE(result) == SVt_RV && SvTYPE(SvRV(result)) == SVt_PVHV)
+     {
+         hvr = (HV *) SvRV(result);
+         hv_iterinit(hvr);
+
+         while ((val = hv_iternextsv(hvr, &key, &klen)))
+         {
+             if (exactly_one_field)
+                 ereport(ERROR,
+                         (errcode(ERRCODE_UNDEFINED_COLUMN),
+                          errmsg("Perl hash contains nonexistent column \"%s\"",
+                                 key)));
+             exactly_one_field = true;
+             result = val;
+         }
+
+         if (!exactly_one_field)
+             ereport(ERROR,
+                     (errcode(ERRCODE_UNDEFINED_COLUMN),
+                      errmsg("Perl hash is empty")));
+
+         hv_iterinit(hvr);
+     }
+
+     return result;
+ }
Index: src/pl/plperl/expected/plperl.out
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plperl/expected/plperl.out,v
retrieving revision 1.7
retrieving revision 1.8
diff -c -r1.7 -r1.8
*** src/pl/plperl/expected/plperl.out    5 Mar 2006 16:40:51 -0000    1.7
--- src/pl/plperl/expected/plperl.out    13 Aug 2006 02:37:11 -0000    1.8
***************
*** 468,470 ****
--- 468,579 ----
                       4
  (2 rows)

+ ---
+ --- Some OUT and OUT array tests
+ ---
+ CREATE OR REPLACE FUNCTION test_out_params(OUT a varchar, OUT b varchar) AS $$
+   return { a=> 'ahoj', b=>'svete'};
+ $$ LANGUAGE plperl;
+ SELECT '01' AS i, * FROM test_out_params();
+  i  |  a   |   b
+ ----+------+-------
+  01 | ahoj | svete
+ (1 row)
+
+ CREATE OR REPLACE FUNCTION test_out_params_array(OUT a varchar[], OUT b varchar[]) AS $$
+   return { a=> ['ahoj'], b=>['svete']};
+ $$ LANGUAGE plperl;
+ SELECT '02' AS i, * FROM test_out_params_array();
+ ERROR:  array value must start with "{" or dimension information
+ CREATE OR REPLACE FUNCTION test_out_params_set(OUT a varchar, out b varchar) RETURNS SETOF RECORD AS $$
+   return_next { a=> 'ahoj', b=>'svete'};
+   return_next { a=> 'ahoj', b=>'svete'};
+   return_next { a=> 'ahoj', b=>'svete'};
+ $$ LANGUAGE plperl;
+ SELECT '03' AS I,* FROM test_out_params_set();
+  i  |  a   |   b
+ ----+------+-------
+  03 | ahoj | svete
+  03 | ahoj | svete
+  03 | ahoj | svete
+ (3 rows)
+
+ CREATE OR REPLACE FUNCTION test_out_params_set_array(OUT a varchar[], out b varchar[]) RETURNS SETOF RECORD AS $$
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+ $$ LANGUAGE plperl;
+ SELECT '04' AS I,* FROM test_out_params_set_array();
+ ERROR:  error from Perl function: array value must start with "{" or dimension information at line 2.
+ DROP FUNCTION test_out_params();
+ DROP FUNCTION test_out_params_set();
+ DROP FUNCTION test_out_params_array();
+ DROP FUNCTION test_out_params_set_array();
+ -- one out argument can be returned as scalar or hash
+ CREATE OR REPLACE FUNCTION test01(OUT a varchar) AS $$
+   return 'ahoj';
+ $$ LANGUAGE plperl ;
+ SELECT '01' AS i,* FROM test01();
+  i  |  a
+ ----+------
+  01 | ahoj
+ (1 row)
+
+ CREATE OR REPLACE FUNCTION test02(OUT a varchar[]) AS $$
+   return {a=>['ahoj']};
+ $$ LANGUAGE plperl;
+ SELECT '02' AS i,a[1] FROM test02();
+ ERROR:  array value must start with "{" or dimension information
+ CREATE OR REPLACE FUNCTION test03(OUT a varchar[]) RETURNS SETOF varchar[] AS $$
+   return_next { a=> ['ahoj']};
+   return_next { a=> ['ahoj']};
+   return_next { a=> ['ahoj']};
+ $$ LANGUAGE plperl;
+ SELECT '03' AS i,* FROM test03();
+ ERROR:  error from Perl function: array value must start with "{" or dimension information at line 2.
+ CREATE OR REPLACE FUNCTION test04() RETURNS SETOF VARCHAR[] AS $$
+   return_next ['ahoj'];
+   return_next ['ahoj'];
+ $$ LANGUAGE plperl;
+ SELECT '04' AS i,* FROM test04();
+ ERROR:  error from Perl function: array value must start with "{" or dimension information at line 2.
+ CREATE OR REPLACE FUNCTION test05(OUT a varchar) AS $$
+   return {a=>'ahoj'};
+ $$ LANGUAGE plperl;
+ SELECT '05' AS i,a FROM test05();
+  i  |        a
+ ----+-----------------
+  05 | HASH(0x8558f9c)
+ (1 row)
+
+ CREATE OR REPLACE FUNCTION test06(OUT a varchar) RETURNS SETOF varchar AS $$
+   return_next { a=> 'ahoj'};
+   return_next { a=> 'ahoj'};
+   return_next { a=> 'ahoj'};
+ $$ LANGUAGE plperl;
+ SELECT '06' AS i,* FROM test06();
+  i  |        a
+ ----+-----------------
+  06 | HASH(0x8559230)
+  06 | HASH(0x8559230)
+  06 | HASH(0x8559230)
+ (3 rows)
+
+ CREATE OR REPLACE FUNCTION test07() RETURNS SETOF VARCHAR AS $$
+   return_next 'ahoj';
+   return_next 'ahoj';
+ $$ LANGUAGE plperl;
+ SELECT '07' AS i,* FROM test07();
+  i  | test07
+ ----+--------
+  07 | ahoj
+  07 | ahoj
+ (2 rows)
+
+ DROP FUNCTION test01();
+ DROP FUNCTION test02();
+ DROP FUNCTION test03();
+ DROP FUNCTION test04();
+ DROP FUNCTION test05();
+ DROP FUNCTION test06();
+ DROP FUNCTION test07();
Index: src/pl/plperl/sql/plperl.sql
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plperl/sql/plperl.sql,v
retrieving revision 1.9
retrieving revision 1.10
diff -c -r1.9 -r1.10
*** src/pl/plperl/sql/plperl.sql    12 Aug 2006 04:16:45 -0000    1.9
--- src/pl/plperl/sql/plperl.sql    13 Aug 2006 02:37:11 -0000    1.10
***************
*** 337,339 ****
--- 337,423 ----
  $$ LANGUAGE plperl;
  SELECT * from perl_spi_prepared_set(1,2);

+ ---
+ --- Some OUT and OUT array tests
+ ---
+
+ CREATE OR REPLACE FUNCTION test_out_params(OUT a varchar, OUT b varchar) AS $$
+   return { a=> 'ahoj', b=>'svete'};
+ $$ LANGUAGE plperl;
+ SELECT '01' AS i, * FROM test_out_params();
+
+ CREATE OR REPLACE FUNCTION test_out_params_array(OUT a varchar[], OUT b varchar[]) AS $$
+   return { a=> ['ahoj'], b=>['svete']};
+ $$ LANGUAGE plperl;
+ SELECT '02' AS i, * FROM test_out_params_array();
+
+ CREATE OR REPLACE FUNCTION test_out_params_set(OUT a varchar, out b varchar) RETURNS SETOF RECORD AS $$
+   return_next { a=> 'ahoj', b=>'svete'};
+   return_next { a=> 'ahoj', b=>'svete'};
+   return_next { a=> 'ahoj', b=>'svete'};
+ $$ LANGUAGE plperl;
+ SELECT '03' AS I,* FROM test_out_params_set();
+
+ CREATE OR REPLACE FUNCTION test_out_params_set_array(OUT a varchar[], out b varchar[]) RETURNS SETOF RECORD AS $$
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+   return_next { a=> ['ahoj'], b=>['velky','svete']};
+ $$ LANGUAGE plperl;
+ SELECT '04' AS I,* FROM test_out_params_set_array();
+
+
+ DROP FUNCTION test_out_params();
+ DROP FUNCTION test_out_params_set();
+ DROP FUNCTION test_out_params_array();
+ DROP FUNCTION test_out_params_set_array();
+
+ -- one out argument can be returned as scalar or hash
+ CREATE OR REPLACE FUNCTION test01(OUT a varchar) AS $$
+   return 'ahoj';
+ $$ LANGUAGE plperl ;
+ SELECT '01' AS i,* FROM test01();
+
+ CREATE OR REPLACE FUNCTION test02(OUT a varchar[]) AS $$
+   return {a=>['ahoj']};
+ $$ LANGUAGE plperl;
+ SELECT '02' AS i,a[1] FROM test02();
+
+ CREATE OR REPLACE FUNCTION test03(OUT a varchar[]) RETURNS SETOF varchar[] AS $$
+   return_next { a=> ['ahoj']};
+   return_next { a=> ['ahoj']};
+   return_next { a=> ['ahoj']};
+ $$ LANGUAGE plperl;
+ SELECT '03' AS i,* FROM test03();
+
+ CREATE OR REPLACE FUNCTION test04() RETURNS SETOF VARCHAR[] AS $$
+   return_next ['ahoj'];
+   return_next ['ahoj'];
+ $$ LANGUAGE plperl;
+ SELECT '04' AS i,* FROM test04();
+
+ CREATE OR REPLACE FUNCTION test05(OUT a varchar) AS $$
+   return {a=>'ahoj'};
+ $$ LANGUAGE plperl;
+ SELECT '05' AS i,a FROM test05();
+
+ CREATE OR REPLACE FUNCTION test06(OUT a varchar) RETURNS SETOF varchar AS $$
+   return_next { a=> 'ahoj'};
+   return_next { a=> 'ahoj'};
+   return_next { a=> 'ahoj'};
+ $$ LANGUAGE plperl;
+ SELECT '06' AS i,* FROM test06();
+
+ CREATE OR REPLACE FUNCTION test07() RETURNS SETOF VARCHAR AS $$
+   return_next 'ahoj';
+   return_next 'ahoj';
+ $$ LANGUAGE plperl;
+ SELECT '07' AS i,* FROM test07();
+
+ DROP FUNCTION test01();
+ DROP FUNCTION test02();
+ DROP FUNCTION test03();
+ DROP FUNCTION test04();
+ DROP FUNCTION test05();
+ DROP FUNCTION test06();
+ DROP FUNCTION test07();
+