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Re: PL/PGSQL: Dynamic Record Introspection

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Titus von Boxberg <ut(at)bhi-hamburg(dot)de>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Neil Conway <neilc(at)samurai(dot)com>,pgsql-patches(at)postgresql(dot)org
Subject: Re: PL/PGSQL: Dynamic Record Introspection
Date: 2005-07-31 02:36:05
Message-ID: 200507310236.j6V2a5g04335@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-patches
This has been saved for the 8.2 release:

	http://momjian.postgresql.org/cgi-bin/pgpatches_hold

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

Titus von Boxberg wrote:
> Tom Lane schrieb:
> > "Titus von Boxberg" <ut(at)bhi-hamburg(dot)de> writes:
> > It works for me if we want to have an "NFIELDS" construct.  Personally
> > I'm still not convinced that we need one --- what's the use-case?
> I have removed the NFIELDS construct
> > 
> > 
> > I'd prefer arbitrary expression, but I suppose there's no harm in doing
> > the simple case first and generalizing if there's demand.
> I took the "no harm" way.
> 
> Attached please find the updated patch.
> The patch is against HEAD of 050721.
> 
> I switched the syntax to your proposal, renamed the functions
> in pl_comp.c and updated the sgml doc source and regression
> test files accordingly.
> 
> Regards
> Titus
> 

> *** ./doc/src/sgml/plpgsql.sgml.orig	Sat Jul  2 08:59:47 2005
> --- ./doc/src/sgml/plpgsql.sgml	Sat Jul 23 17:24:54 2005
> ***************
> *** 867,872 ****
> --- 867,921 ----
>      </para>
>   
>      <para>
> +     To obtain the values of the fields the record is made up of,
> +     the record variable can be qualified with the column or field
> +     name. This can be done either by literally using the column name
> +     or the column name for indexing the record can be taken out of a scalar
> +     variable. The syntax for this notation is Record_variable.(IndexVariable).
> +     To get information about the column field names of the record, 
> +     a
>  special expression exists that returns all column names as an array: 
> +     RecordVariable.(*) .
> +     Thus, the RECORD can be viewed
> +     as an associative array that allows for introspection of it's contents.
> +     This feature is especially useful for writing generic triggers that
> +     operate on records with unknown structure.
> +     Here is an example procedure that shows column names and values
> +     of the predefined record NEW in a trigger procedure:
> + <programlisting>
> + 
> + CREATE OR REPLACE FUNCTION show_associative_records() RETURNS TRIGGER AS $$
> + 	DECLARE
> + 		colname		TEXT;
> + 		colcontent	TEXT;
> + 		colnames	TEXT[];
> + 		coln		INT4;
> + 		coli		INT4;
> + 	BEGIN
> + -- obtain an array with all field names of the record
> + 		colnames := NEW.(*);
> + 		RAISE NOTICE 'All column names of test record: %', colnames;
> + -- show field names and contents of record
> + 		coli := 1;
> + 		coln := array_upper(colnames,1);
> + 		RAISE NOTICE 'Number of columns in NEW: %', coln;
> + 		FOR coli IN 1 .. coln LOOP
> + 			colname := colnames[coli];
> + 			colcontent := NEW.(colname);
> + 			RAISE NOTICE 'column % of NEW: %', quote_ident(colname), quote_literal(colcontent);
> + 		END LOOP;
> + -- Do it with a fixed field name:
> + -- will have to know the column name
> + 		RAISE NOTICE 'column someint of NEW: %', quote_literal(NEW.someint);
> + 		RETURN NULL;
> + 	END;
> + $$ LANGUAGE plpgsql;
> + --CREATE TABLE test_records (someint INT8, somestring TEXT);
> + --CREATE TRIGGER tr_test_record BEFORE INSERT ON test_records FOR EACH ROW EXECUTE PROCEDURE show_associative_records();
> + 
> + </programlisting>
> +    </para>
> + 
> +    <para>
>       Note that <literal>RECORD</> is not a true data type, only a placeholder.
>       One should also realize that when a <application>PL/pgSQL</application>
>       function is declared to return type <type>record</>, this is not quite the
> *** ./src/pl/plpgsql/src/pl_comp.c.orig	Wed Jul  6 16:42:10 2005
> --- ./src/pl/plpgsql/src/pl_comp.c	Thu Jul 21 21:28:15 2005
> ***************
> *** 995,1001 ****
>   
>   				new = palloc(sizeof(PLpgSQL_recfield));
>   				new->dtype = PLPGSQL_DTYPE_RECFIELD;
> ! 				new->fieldname = pstrdup(cp[1]);
>   				new->recparentno = ns->itemno;
>   
>   				plpgsql_adddatum((PLpgSQL_datum *) new);
> --- 995,1002 ----
>   
>   				new = palloc(sizeof(PLpgSQL_recfield));
>   				new->dtype = PLPGSQL_DTYPE_RECFIELD;
> ! 				new->fieldindex.fieldname = pstrdup(cp[1]);
> ! 				new->fieldindex_flag = RECFIELD_USE_FIELDNAME;
>   				new->recparentno = ns->itemno;
>   
>   				plpgsql_adddatum((PLpgSQL_datum *) new);
> ***************
> *** 1101,1107 ****
>   
>   				new = palloc(sizeof(PLpgSQL_recfield));
>   				new->dtype = PLPGSQL_DTYPE_RECFIELD;
> ! 				new->fieldname = pstrdup(cp[2]);
>   				new->recparentno = ns->itemno;
>   
>   				plpgsql_adddatum((PLpgSQL_datum *) new);
> --- 1102,1109 ----
>   
>   				new = palloc(sizeof(PLpgSQL_recfield));
>   				new->dtype = PLPGSQL_DTYPE_RECFIELD;
> ! 				new->fieldindex.fieldname = pstrdup(cp[2]);
> ! 				new->fieldindex_flag = RECFIELD_USE_FIELDNAME;
>   				new->recparentno = ns->itemno;
>   
>   				plpgsql_adddatum((PLpgSQL_datum *) new);
> ***************
> *** 1550,1555 ****
> --- 1552,1683 ----
>   	MemoryContextSwitchTo(oldCxt);
>   	return T_DTYPE;
>   }
> + 
> + /* ----------
> +  * plpgsql_parse_recindex
> +  * lookup associative index into record
> +  * ----------
> +  */
> + int
> + plpgsql_parse_recindex(char *word)
> + {
> + 	PLpgSQL_nsitem *ns1, *ns2;
> + 	char		*cp[2];
> + 	int		ret = T_ERROR;
> + 	char		*fieldvar;
> + 	int		fl;
> + 
> + 	/* Do case conversion and word separation */
> + 	plpgsql_convert_ident(word, cp, 2);
> + 	Assert(cp[1] != NULL);
> + 
> + 	/* cleanup the "(identifier)" string to "identifier" */
> + 	fieldvar = cp[1];
> + 	Assert(*fieldvar == '(');
> + 	++fieldvar;	/* get rid of ( */
> + 
> + 	fl = strlen(fieldvar);
> + 	Assert(fieldvar[fl-1] == ')');
> + 	fieldvar[fl-1] = 0; /* get rid of ) */
> + 
> + 	/*
> + 	 * Lookup the first word
> + 	 */
> + 	ns1 = plpgsql_ns_lookup(cp[0], NULL);
> + 	if ( ns1 == NULL )
> + 	{
> + 		pfree(cp[0]);
> + 		pfree(cp[1]);
> + 		return T_ERROR;
> + 	}
> + 
> + 	ns2 = plpgsql_ns_lookup(fieldvar, NULL);
> + 	pfree(cp[0]);
> + 	pfree(cp[1]);
> + 	if ( ns2 == NULL )	/* name lookup failed */
> + 		return T_ERROR;
> + 
> + 	switch (ns1->itemtype)
> + 	{
> + 		case PLPGSQL_NSTYPE_REC:
> + 			{
> + 				/*
> + 				 * First word is a record name, so second word must be an
> + 				 * variable holding the field name in this record.
> + 				 */
> + 				if ( ns2->itemtype == PLPGSQL_NSTYPE_VAR ) {
> + 					PLpgSQL_recfield *new;
> + 
> + 					new = palloc(sizeof(PLpgSQL_recfield));
> + 					new->dtype = PLPGSQL_DTYPE_RECFIELD;
> + 					new->fieldindex.indexvar_no = ns2->itemno;
> + 					new->fieldindex_flag = RECFIELD_USE_INDEX_VAR;
> + 					new->recparentno = ns1->itemno;
> + 
> + 					plpgsql_adddatum((PLpgSQL_datum *) new);
> + 
> + 					plpgsql_yylval.scalar = (PLpgSQL_datum *) new;
> + 					ret =  T_SCALAR;
> + 				} 
> + 				break;
> + 			}
> + 		default:
> + 			break;
> + 	}
> + 	return ret;
> + } 
> + 
> + 
> + /* ----------
> +  * plpgsql_parse_recfieldnames
> +  * create fieldnames of a record
> +  * ----------
> +  */
> + int
> + plpgsql_parse_recfieldnames(char *word)
> + {
> + 	PLpgSQL_nsitem	*ns1;
> + 	char		*cp[2];
> + 	int		ret = T_ERROR;
> + 
> + 	/* Do case conversion and word separation */
> + 	plpgsql_convert_ident(word, cp, 2);
> + 
> + 	/*
> + 	 * Lookup the first word
> + 	 */
> + 	ns1 = plpgsql_ns_lookup(cp[0], NULL);
> + 	if ( ns1 == NULL )
> + 	{
> + 		pfree(cp[0]);
> + 		pfree(cp[1]);
> + 		return T_ERROR;
> + 	}
> + 
> + 	pfree(cp[0]);
> + 	pfree(cp[1]);
> + 
> + 	switch (ns1->itemtype)
> + 	{
> + 		case PLPGSQL_NSTYPE_REC:
> + 			{
> + 				PLpgSQL_recfieldproperties *new;
> + 
> + 				new = palloc(sizeof(PLpgSQL_recfieldproperties));
> + 				new->dtype = PLPGSQL_DTYPE_RECFIELDNAMES;
> + 				new->recparentno = ns1->itemno;
> + 				new->save_fieldnames = NULL;
> + 				plpgsql_adddatum((PLpgSQL_datum *) new);
> + 				plpgsql_yylval.scalar = (PLpgSQL_datum *) new;
> + 				ret =  T_SCALAR;	/* ??? */
> + 				break;
> + 			}
> + 		default:
> + 			break;
> + 	}
> + 	return ret;
> + }
> + 
>   
>   /*
>    * plpgsql_build_variable - build a datum-array entry of a given
> *** ./src/pl/plpgsql/src/pl_exec.c.orig	Sun Jun 26 22:05:42 2005
> --- ./src/pl/plpgsql/src/pl_exec.c	Sat Jul 23 17:13:32 2005
> ***************
> *** 716,721 ****
> --- 716,722 ----
>   		case PLPGSQL_DTYPE_RECFIELD:
>   		case PLPGSQL_DTYPE_ARRAYELEM:
>   		case PLPGSQL_DTYPE_TRIGARG:
> + 		case PLPGSQL_DTYPE_RECFIELDNAMES:
>   			/*
>   			 * These datum records are read-only at runtime, so no need
>   			 * to copy them
> ***************
> *** 825,830 ****
> --- 826,832 ----
>   
>   			case PLPGSQL_DTYPE_RECFIELD:
>   			case PLPGSQL_DTYPE_ARRAYELEM:
> + 			case PLPGSQL_DTYPE_RECFIELDNAMES:
>   				break;
>   
>   			default:
> ***************
> *** 2146,2151 ****
> --- 2148,2155 ----
>   static void
>   exec_eval_cleanup(PLpgSQL_execstate *estate)
>   {
> + 	int		i;
> + 	ArrayType	*a;
>   	/* Clear result of a full SPI_execute */
>   	if (estate->eval_tuptable != NULL)
>   		SPI_freetuptable(estate->eval_tuptable);
> ***************
> *** 2154,2159 ****
> --- 2158,2171 ----
>   	/* Clear result of exec_eval_simple_expr (but keep the econtext) */
>   	if (estate->eval_econtext != NULL)
>   		ResetExprContext(estate->eval_econtext);
> + 	for ( i = 0; i < estate->ndatums; ++i ) {
> + 		if ( estate->datums[i]->dtype == PLPGSQL_DTYPE_RECFIELDNAMES ) {
> + 			a = ((PLpgSQL_recfieldproperties *)(estate->datums[i]))->save_fieldnames;
> + 			if ( a )
> + 				pfree(a);
> + 			((PLpgSQL_recfieldproperties *)(estate->datums[i]))->save_fieldnames = NULL;
> + 		}
> + 	}
>   }
>   
>   
> ***************
> *** 3154,3165 ****
>   				 * Get the number of the records field to change and the
>   				 * number of attributes in the tuple.
>   				 */
> ! 				fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
> ! 				if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 					ereport(ERROR,
> ! 							(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 							 errmsg("record \"%s\" has no field \"%s\"",
> ! 									rec->refname, recfield->fieldname)));
>   				fno--;
>   				natts = rec->tupdesc->natts;
>   
> --- 3166,3200 ----
>   				 * Get the number of the records field to change and the
>   				 * number of attributes in the tuple.
>   				 */
> ! 				if ( recfield->fieldindex_flag == RECFIELD_USE_FIELDNAME ) {
> ! 					fno = SPI_fnumber(rec->tupdesc, recfield->fieldindex.fieldname);
> ! 					if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								 errmsg("record \"%s\" has no field \"%s\"",
> ! 										rec->refname, recfield->fieldindex.fieldname)));
> ! 				}
> ! 				else if ( recfield->fieldindex_flag == RECFIELD_USE_INDEX_VAR ) {
> ! 					PLpgSQL_var * idxvar = (PLpgSQL_var *) (estate->datums[recfield->fieldindex.indexvar_no]);
> ! 					char * fname = convert_value_to_string(idxvar->value, idxvar->datatype->typoid);
> ! 					if ( fname == NULL )
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								errmsg("record \"%s\": cannot evaluate variable to record index string",
> ! 										rec->refname)));
> ! 					fno = SPI_fnumber(rec->tupdesc, fname);
> ! 					pfree(fname);
> ! 					if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								 errmsg("record \"%s\" has no field \"%s\"",
> ! 										rec->refname, fname)));
> ! 				}
> ! 				else
> ! 					ereport(ERROR,
> ! 						(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 						errmsg("record \"%s\": internal error",
> ! 									rec->refname)));
>   				fno--;
>   				natts = rec->tupdesc->natts;
>   
> ***************
> *** 3497,3518 ****
>   					   errmsg("record \"%s\" is not assigned yet",
>   							  rec->refname),
>   					   errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
> ! 				fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
> ! 				if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 					ereport(ERROR,
> ! 							(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 							 errmsg("record \"%s\" has no field \"%s\"",
> ! 									rec->refname, recfield->fieldname)));
> ! 				*typeid = SPI_gettypeid(rec->tupdesc, fno);
> ! 				*value = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
> ! 				if (expectedtypeid != InvalidOid && expectedtypeid != *typeid)
> ! 					ereport(ERROR,
> ! 							(errcode(ERRCODE_DATATYPE_MISMATCH),
> ! 							 errmsg("type of \"%s.%s\" does not match that when preparing the plan",
> ! 									rec->refname, recfield->fieldname)));
> ! 				break;
> ! 			}
> ! 
>   		case PLPGSQL_DTYPE_TRIGARG:
>   			{
>   				PLpgSQL_trigarg *trigarg = (PLpgSQL_trigarg *) datum;
> --- 3532,3656 ----
>   					   errmsg("record \"%s\" is not assigned yet",
>   							  rec->refname),
>   					   errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
> ! 				if ( recfield->fieldindex_flag == RECFIELD_USE_FIELDNAME ) {
> ! 					fno = SPI_fnumber(rec->tupdesc, recfield->fieldindex.fieldname);
> ! 					if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								 errmsg("record \"%s\" has no field \"%s\"",
> ! 										rec->refname, recfield->fieldindex.fieldname)));
> ! 				}
> ! 				else if ( recfield->fieldindex_flag == RECFIELD_USE_INDEX_VAR ) {
> ! 					PLpgSQL_var * idxvar = (PLpgSQL_var *) (estate->datums[recfield->fieldindex.indexvar_no]);
> ! 					char * fname = convert_value_to_string(idxvar->value, idxvar->datatype->typoid);
> ! 					if ( fname == NULL )
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								errmsg("record \"%s\": cannot evaluate variable to record index string",
> ! 										rec->refname)));
> ! 					fno = SPI_fnumber(rec->tupdesc, fname);
> ! 					pfree(fname);
> ! 					if (fno == SPI_ERROR_NOATTRIBUTE)
> ! 						ereport(ERROR,
> ! 								(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 								 errmsg("record \"%s\" has no field \"%s\"",
> ! 										rec->refname, fname)));
> ! 				}
> ! 				else
> ! 					ereport(ERROR,
> ! 						(errcode(ERRCODE_UNDEFINED_COLUMN),
> ! 						errmsg("record \"%s\": internal error",
> ! 								rec->refname)));
> ! 
> ! 				/* Do not allow typeids to become "narrowed" by InvalidOids 
> ! 				causing specialized typeids from the tuple restricting the destination */
> ! 				if ( expectedtypeid != InvalidOid && expectedtypeid != SPI_gettypeid(rec->tupdesc, fno) ) {
> ! 					Datum cval = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
> ! 					cval =   exec_simple_cast_value(cval,
> ! 									SPI_gettypeid(rec->tupdesc, fno),
> ! 									expectedtypeid,
> ! 									-1,
> ! 									isnull);
> ! 
> ! 					*value = cval;
> ! 					*typeid = expectedtypeid;
> ! 					/* ereport(ERROR,
> ! 							(errcode(ERRCODE_DATATYPE_MISMATCH),
> ! 							 errmsg("type of \"%s\" does not match that when preparing the plan",
> ! 									rec->refname)));
> ! 					*/
> ! 				} 
> ! 				else { /* expected typeid matches */
> ! 					*value = SPI_getbinval(rec->tup, rec->tupdesc, fno, isnull);
> ! 					*typeid = SPI_gettypeid(rec->tupdesc, fno);
> ! 				} 
> ! 				break;
> ! 			}
> ! 
> ! 		case PLPGSQL_DTYPE_RECFIELDNAMES:
> ! 			/* Construct array datum from record field names */
> ! 			{
> ! 				Oid			arraytypeid,
> ! 							arrayelemtypeid = TEXTOID;
> ! 				int16			arraytyplen,
> ! 							elemtyplen;
> ! 				bool			elemtypbyval;
> ! 				char			elemtypalign;
> ! 				ArrayType		*arrayval;
> ! 				PLpgSQL_recfieldproperties * recfp = (PLpgSQL_recfieldproperties *) datum;
> ! 				PLpgSQL_rec		*rec = (PLpgSQL_rec *) (estate->datums[recfp->recparentno]);
> ! 				int			fc, tfc = 0;
> ! 				Datum			*arrayelems;
> ! 				char			*fieldname;
> ! 
> ! 				if (!HeapTupleIsValid(rec->tup))
> ! 					ereport(ERROR,
> ! 					  (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
> ! 					   errmsg("record \"%s\" is not assigned yet",
> ! 							  rec->refname),
> ! 					   errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
> ! 				arrayelems = palloc(sizeof(Datum) * rec->tupdesc->natts);
> ! 				arraytypeid = get_array_type(arrayelemtypeid);
> ! 				arraytyplen = get_typlen(arraytypeid);
> ! 				get_typlenbyvalalign(arrayelemtypeid,
> ! 						     &elemtyplen,
> ! 						     &elemtypbyval,
> ! 						     &elemtypalign);
> ! 
> ! 				if ( expectedtypeid != InvalidOid && expectedtypeid != arraytypeid )
> ! 					ereport(ERROR,
> ! 							(errcode(ERRCODE_DATATYPE_MISMATCH),
> ! 							 errmsg("type of \"%s\" does not match array type when preparing the plan",
> ! 									rec->refname)));
> ! 				for ( fc = 0; fc < rec->tupdesc->natts; ++fc ) {
> ! 					fieldname = SPI_fname(rec->tupdesc, fc+1);
> ! 					if ( fieldname ) {
> ! 						arrayelems[fc] = DirectFunctionCall1(textin, CStringGetDatum(fieldname));
> ! 						pfree(fieldname);
> ! 						++tfc;
> ! 					} 
> ! 				} 
> ! 				arrayval = construct_array(arrayelems, tfc,
> ! 							 arrayelemtypeid,
> ! 							 elemtyplen,
> ! 							 elemtypbyval,
> ! 							 elemtypalign);
> ! 
> ! 
> ! 				/* construct_array copies data; free temp elem array */
> ! 				for ( fc = 0; fc < tfc; ++fc )
> ! 					pfree(DatumGetPointer(arrayelems[fc]));
> ! 				pfree(arrayelems);
> ! 				*value = PointerGetDatum(arrayval);
> ! 				*typeid = arraytypeid;
> ! 				*isnull = false;
> ! 				/* need to save the pointer because otherwise it does not get freed */
> ! 				if ( recfp->save_fieldnames )
> ! 					pfree(recfp->save_fieldnames);
> ! 				recfp->save_fieldnames = arrayval;
> ! 				break;
> ! 			}
> ! 
>   		case PLPGSQL_DTYPE_TRIGARG:
>   			{
>   				PLpgSQL_trigarg *trigarg = (PLpgSQL_trigarg *) datum;
> ***************
> *** 3610,3616 ****
> --- 3748,3790 ----
>   	 */
>   	if (expr->plan == NULL)
>   		exec_prepare_plan(estate, expr);
> + 	else {
> + 		/*
> + 		 * check for any subexpressions with varying type in the expression 
> + 		 * currently (July 05), this is a record field of a record indexed by a variable
> + 		 */
> + 		int			i;
> + 		PLpgSQL_datum		*d;
> + 		PLpgSQL_recfield	*rf;
> + 		for ( i = 0; i < expr->nparams; ++i ) {
> + 			d = estate->datums[expr->params[i]];
> + 			if ( d->dtype == PLPGSQL_DTYPE_RECFIELD ) {
> + 				rf = (PLpgSQL_recfield *)d;
> + 				if ( rf->fieldindex_flag == RECFIELD_USE_INDEX_VAR )
> + 					break;
> + 			}
> + 		}
> + 		if ( i < expr->nparams ) { /* expr may change it's type */
> + 			/* Make sure expr is not in the list of active simple expressions
> + 			   because exec_prepare_plan()/exec_simple_check_plan()... 
> + 			   will destroy the link to the next simple expression */
> + 			PLpgSQL_expr *e, *enext;
> + 			PLpgSQL_expr **eprevnext = &active_simple_exprs;
> + 			for (e = active_simple_exprs; e; e = enext)
> + 			{
> + 				enext = e->expr_simple_next;
> + 				if ( e == expr ) /* found us in the list */
> + 					*eprevnext = enext; /* discard us */
> + 				else
> + 					eprevnext = &(e->expr_simple_next);
> + 			}
>   
> + 			/* now discard the plan and get new one */
> + 			SPI_freeplan(expr->plan);
> + 			expr->plan = NULL;
> + 			exec_prepare_plan(estate, expr);
> + 		}
> + 	}
>   	/*
>   	 * If this is a simple expression, bypass SPI and use the executor
>   	 * directly
> *** ./src/pl/plpgsql/src/pl_funcs.c.orig	Wed Jun 22 01:35:02 2005
> --- ./src/pl/plpgsql/src/pl_funcs.c	Thu Jul 21 21:03:40 2005
> ***************
> *** 1066,1074 ****
>   				printf("REC %s\n", ((PLpgSQL_rec *) d)->refname);
>   				break;
>   			case PLPGSQL_DTYPE_RECFIELD:
> ! 				printf("RECFIELD %-16s of REC %d\n",
> ! 					   ((PLpgSQL_recfield *) d)->fieldname,
> ! 					   ((PLpgSQL_recfield *) d)->recparentno);
>   				break;
>   			case PLPGSQL_DTYPE_ARRAYELEM:
>   				printf("ARRAYELEM of VAR %d subscript ",
> --- 1066,1078 ----
>   				printf("REC %s\n", ((PLpgSQL_rec *) d)->refname);
>   				break;
>   			case PLPGSQL_DTYPE_RECFIELD:
> ! 				if ( ((PLpgSQL_recfield *) d)->fieldindex_flag == RECFIELD_USE_FIELDNAME )
> ! 					printf("RECFIELD %-16s of REC %d\n",
> ! 						   ((PLpgSQL_recfield *) d)->fieldindex.fieldname,
> ! 						   ((PLpgSQL_recfield *) d)->recparentno);
> ! 				else
> ! 					printf("RECFIELD Variable of REC %d\n",
> ! 						   ((PLpgSQL_recfield *) d)->recparentno);
>   				break;
>   			case PLPGSQL_DTYPE_ARRAYELEM:
>   				printf("ARRAYELEM of VAR %d subscript ",
> *** ./src/pl/plpgsql/src/plpgsql.h.orig	Thu Jul 21 21:00:57 2005
> --- ./src/pl/plpgsql/src/plpgsql.h	Thu Jul 21 21:15:42 2005
> ***************
> *** 73,79 ****
>   	PLPGSQL_DTYPE_RECFIELD,
>   	PLPGSQL_DTYPE_ARRAYELEM,
>   	PLPGSQL_DTYPE_EXPR,
> ! 	PLPGSQL_DTYPE_TRIGARG
>   };
>   
>   /* ----------
> --- 73,80 ----
>   	PLPGSQL_DTYPE_RECFIELD,
>   	PLPGSQL_DTYPE_ARRAYELEM,
>   	PLPGSQL_DTYPE_EXPR,
> ! 	PLPGSQL_DTYPE_TRIGARG,
> ! 	PLPGSQL_DTYPE_RECFIELDNAMES
>   };
>   
>   /* ----------
> ***************
> *** 269,278 ****
>   {								/* Field in record */
>   	int			dtype;
>   	int			rfno;
> ! 	char	   *fieldname;
>   	int			recparentno;	/* dno of parent record */
>   } PLpgSQL_recfield;
>   
>   
>   typedef struct
>   {								/* Element of array variable */
> --- 270,294 ----
>   {								/* Field in record */
>   	int			dtype;
>   	int			rfno;
> ! 	union {
> ! 		char	*fieldname;
> ! 		int	indexvar_no;		/* dno of variable holding index string */
> ! 	} fieldindex;
> ! 	enum {
> ! 		RECFIELD_USE_FIELDNAME,
> ! 		RECFIELD_USE_INDEX_VAR,
> ! 	}	fieldindex_flag;
>   	int			recparentno;	/* dno of parent record */
>   } PLpgSQL_recfield;
>   
> + typedef struct
> + {								/* Field in record */
> + 	int			dtype;
> + 	int			rfno;
> + 	int			recparentno;			/* dno of parent record */
> + 	ArrayType *		save_fieldnames;
> + } PLpgSQL_recfieldproperties;
> + 
>   
>   typedef struct
>   {								/* Element of array variable */
> ***************
> *** 678,683 ****
> --- 694,701 ----
>   extern int	plpgsql_parse_tripwordtype(char *word);
>   extern int	plpgsql_parse_wordrowtype(char *word);
>   extern int	plpgsql_parse_dblwordrowtype(char *word);
> + extern int	plpgsql_parse_recfieldnames(char *word);
> + extern int	plpgsql_parse_recindex(char *word);
>   extern PLpgSQL_type *plpgsql_parse_datatype(const char *string);
>   extern PLpgSQL_type *plpgsql_build_datatype(Oid typeOid, int32 typmod);
>   extern PLpgSQL_variable *plpgsql_build_variable(const char *refname, int lineno,
> *** ./src/pl/plpgsql/src/scan.l.orig	Sun Jun 26 19:16:07 2005
> --- ./src/pl/plpgsql/src/scan.l	Thu Jul 21 21:28:20 2005
> ***************
> *** 243,248 ****
> --- 243,254 ----
>   {param}{space}*\.{space}*{identifier}{space}*%ROWTYPE	{
>   	plpgsql_error_lineno = plpgsql_scanner_lineno();
>   	return plpgsql_parse_dblwordrowtype(yytext); }
> + {identifier}{space}*\.\(\*\)		{
> + 	plpgsql_error_lineno = plpgsql_scanner_lineno();
> + 	return plpgsql_parse_recfieldnames(yytext); }
> + {identifier}{space}*\.\({identifier}\)		{
> + 	plpgsql_error_lineno = plpgsql_scanner_lineno();
> + 	return plpgsql_parse_recindex(yytext); }
>   
>   {digit}+		{ return T_NUMBER;			}
>   
> *** ./src/test/regress/expected/plpgsql.out.orig	Sat Jul  2 08:59:48 2005
> --- ./src/test/regress/expected/plpgsql.out	Thu Jul 21 22:32:52 2005
> ***************
> *** 2721,2723 ****
> --- 2721,2761 ----
>   $$ language plpgsql;
>   ERROR:  end label "outer_label" specified for unlabelled block
>   CONTEXT:  compile of PL/pgSQL function "end_label4" near line 5
> + -- check introspective records
> + create table ritest (i INT4, t TEXT);
> + insert into ritest (i, t) VALUES (1, 'sometext');
> + create function test_record() returns void as $$
> + declare
> +   cname text;
> +   tval  text;
> +   ival  int4;
> +   tval2 text;
> +   ival2 int4;
> +   columns text[];
> +   r     RECORD;
> + begin
> +   SELECT INTO r * FROM ritest WHERE i = 1;
> +   ival := r.i;
> +   tval := r.t;
> +   RAISE NOTICE 'ival=%, tval=%', ival, tval;
> +   cname := 'i';
> +   ival2 := r.(cname);
> +   cname :='t';
> +   tval2 := r.(cname);
> +   RAISE NOTICE 'ival2=%, tval2=%', ival2, tval2;
> +   columns := r.(*);
> +   RAISE NOTICE 'fieldnames=%', columns;
> +   RETURN;
> + end;
> + $$ language plpgsql;
> + select test_record();
> + NOTICE:  ival=1, tval=sometext
> + NOTICE:  ival2=1, tval2=sometext
> + NOTICE:  fieldnames={i,t}
> +  test_record 
> + -------------
> +  
> +  (1 row)
> + 
> + drop table ritest;
> + drop function test_record();
> *** ./src/test/regress/sql/plpgsql.sql.orig	Thu Jul 21 21:04:43 2005
> --- ./src/test/regress/sql/plpgsql.sql	Thu Jul 21 21:36:11 2005
> ***************
> *** 2280,2282 ****
> --- 2280,2314 ----
>     end loop outer_label;
>   end;
>   $$ language plpgsql;
> + 
> + -- check introspective records
> + create table ritest (i INT4, t TEXT);
> + insert into ritest (i, t) VALUES (1, 'sometext');
> + create function test_record() returns void as $$
> + declare
> +   cname text;
> +   tval  text;
> +   ival  int4;
> +   tval2 text;
> +   ival2 int4;
> +   columns text[];
> +   r     RECORD;
> + begin
> +   SELECT INTO r * FROM ritest WHERE i = 1;
> +   ival := r.i;
> +   tval := r.t;
> +   RAISE NOTICE 'ival=%, tval=%', ival, tval;
> +   cname := 'i';
> +   ival2 := r.(cname);
> +   cname :='t';
> +   tval2 := r.(cname);
> +   RAISE NOTICE 'ival2=%, tval2=%', ival2, tval2;
> +   columns := r.(*);
> +   RAISE NOTICE 'fieldnames=%', columns;
> +   RETURN;
> + end;
> + $$ language plpgsql;
> + select test_record();
> + drop table ritest;
> + drop function test_record();
> + 

> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>        choose an index scan if your joining column's datatypes do not
>        match

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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