replace UNKNOWNOID to TEXTOID

Author: Sofia Kopikova

expected/pg_variables.out

@@ -773,8 +773,8 @@ CLOSE r1_cur;
 COMMIT; -- warning
 RESET client_min_messages;
 -- Clean memory after unsuccessful creation of a variable
-SELECT pgv_insert('vars4', 'r1', row('str1', 'str1')); -- fail
-ERROR:  could not identify a hash function for type unknown
+SELECT pgv_insert('vars4', 'r1', row (('str1'::text, 'str1'::text))); -- fail
+ERROR:  could not identify a hash function for type record
 SELECT package FROM pgv_stats() WHERE package = 'vars4';
  package 
 ---------
@@ -954,28 +954,32 @@ SELECT pgv_select('vars', 'r1');
  (1,str1,str2)
 (1 row)
 
-SELECT pgv_insert('vars', 'r2', row(1, 'str1'));
+SELECT pgv_insert('vars', 'r2', row(1, 'str1')); -- ok, UNKNOWNOID of 'str1' converts to TEXTOID
+ pgv_insert 
+------------
+ 
+(1 row)
+
+SELECT pgv_insert('vars', 'r2', foo) FROM foo; -- ok
  pgv_insert 
 ------------
 
 (1 row)
 
-SELECT pgv_insert('vars', 'r2', foo) FROM foo;
-ERROR:  new record attribute type for attribute number 2 differs from variable "r2" structure.
-HINT:  You may need explicit type casts.
 SELECT pgv_select('vars', 'r2');
  pgv_select 
 ------------
  (1,str1)
-(1 row)
+ (0,str00)
+(2 rows)
 
 SELECT pgv_insert('vars', 'r3', row(1, 'str1'::text));
  pgv_insert 
 ------------
 
 (1 row)
 
-SELECT pgv_insert('vars', 'r3', foo) FROM foo;
+SELECT pgv_insert('vars', 'r3', foo) FROM foo; -- ok, no conversions
  pgv_insert 
 ------------
 
@@ -988,3 +992,37 @@ SELECT pgv_select('vars', 'r3');
  (0,str00)
 (2 rows)
 
+SELECT pgv_insert('vars', 'r4', row(1, 2::int));
+ pgv_insert 
+------------
+ 
+(1 row)
+
+SELECT pgv_insert('vars', 'r4', row(0, 'str1')); -- fail, UNKNOWNOID of 'str1' can't be converted to int
+ERROR:  new record attribute type for attribute number 2 differs from variable "r4" structure.
+HINT:  You may need explicit type casts.
+SELECT pgv_select('vars', 'r4');
+ pgv_select 
+------------
+ (1,2)
+(1 row)
+
+SELECT pgv_insert('vars', 'r5', foo) FROM foo; -- types: int, text
+ pgv_insert 
+------------
+ 
+(1 row)
+
+SELECT pgv_insert('vars', 'r5', row(1, 'str1')); -- ok, UNKNOWNOID of 'str1' converts to TEXTOID
+ pgv_insert 
+------------
+ 
+(1 row)
+
+SELECT pgv_select('vars', 'r5');
+ pgv_select 
+------------
+ (1,str1)
+ (0,str00)
+(2 rows)
+

expected/pg_variables_trans.out

@@ -1858,8 +1858,8 @@ SELECT pgv_insert('package', 'errs',row(1), true);
 (1 row)
 
 -- Variable should not exists in case when error occurs during creation
-SELECT pgv_insert('vars4', 'r1', row('str1', 'str1'));
-ERROR:  could not identify a hash function for type unknown
+SELECT pgv_insert('vars4', 'r1', row (('str1'::text, 'str1'::text)));
+ERROR:  could not identify a hash function for type record
 SELECT pgv_select('vars4', 'r1', 0);
 ERROR:  unrecognized package "vars4"
 -- If variable created and removed in same transaction level,

pg_variables.c

@@ -114,6 +114,10 @@ do { \
 } while(0)
 #endif			/* PG_VERSION_NUM */
 
+/* User controlled GUCs */
+bool convert_unknownoid_guc;
+bool convert_unknownoid;
+
 static HTAB *packagesHash = NULL;
 static MemoryContext ModuleContext = NULL;
 
@@ -701,6 +705,14 @@ variable_insert(PG_FUNCTION_ARGS)
 		/*
 		 * This is the first record for the var_name. Initialize record.
 		 */
+		/* Convert UNKNOWNOID to TEXTOID if needed
+		 * tupdesc may be changed
+		 */
+		if (convert_unknownoid)
+		{
+			coerce_unknown_first_record(&tupdesc, &rec);
+		}
+
 		init_record(record, tupdesc, variable);
 		variable->is_deleted = false;
 	}
@@ -709,8 +721,11 @@ variable_insert(PG_FUNCTION_ARGS)
 		/*
 		 * We need to check attributes of the new row if this is a transient
 		 * record type or if last record has different id.
+		 * Also we convert UNKNOWNOID to TEXTOID if needed.
+		 * tupdesc may be changed
 		 */
-		check_attributes(variable, tupdesc);
+		check_attributes(variable, &rec, tupdesc);
+
 	}
 
 	insert_record(variable, rec);
@@ -791,7 +806,11 @@ variable_update(PG_FUNCTION_ARGS)
 	tupTypmod = HeapTupleHeaderGetTypMod(rec);
 
 	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
-	check_attributes(variable, tupdesc);
+	/*
+	 * Convert UNKNOWNOID to TEXTOID if needed
+	 * tupdesc may be changed
+	 */
+	check_attributes(variable, &rec, tupdesc);
 	ReleaseTupleDesc(tupdesc);
 
 	res = update_record(variable, rec);
@@ -2622,6 +2641,17 @@ freeStatsLists(void)
 void
 _PG_init(void)
 {
+	DefineCustomBoolVariable("pg_variables.convert_unknownoid",
+							 "Use \'TEXT\' format for all values of \'UNKNOWNOID\', default is true.",
+							 NULL,
+						     &convert_unknownoid,
+							 true,
+							 PGC_USERSET,
+							 0, /* FLAGS??? */
+							 NULL,
+							 NULL,
+							 NULL);
+
 	RegisterXactCallback(pgvTransCallback, NULL);
 	RegisterSubXactCallback(pgvSubTransCallback, NULL);
 

pg_variables.h

@@ -16,6 +16,7 @@
 #include "access/tupdesc.h"
 #include "datatype/timestamp.h"
 #include "utils/date.h"
+#include "utils/guc.h"
 #include "utils/hsearch.h"
 #include "utils/numeric.h"
 #include "utils/jsonb.h"
@@ -155,8 +156,12 @@ typedef struct ChangesStackNode
 	MemoryContext ctx;
 }			ChangesStackNode;
 
+/* pg_variables.c */
+extern bool convert_unknownoid;
+
 extern void init_record(RecordVar *record, TupleDesc tupdesc, Variable *variable);
-extern void check_attributes(Variable *variable, TupleDesc tupdesc);
+extern void check_attributes(Variable *variable, HeapTupleHeader *rec, TupleDesc tupdesc);
+extern void coerce_unknown_first_record(TupleDesc *tupdesc, HeapTupleHeader * rec);
 extern void check_record_key(Variable *variable, Oid typid);
 
 extern void insert_record(Variable *variable, HeapTupleHeader tupleHeader);

pg_variables_record.c

@@ -25,8 +25,11 @@
 
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
+#include "parser/parse_type.h"
 #include "utils/builtins.h"
 #include "utils/datum.h"
+#include "utils/lsyscache.h"
+#include "utils/syscache.h"
 #include "utils/memutils.h"
 #include "utils/typcache.h"
 
@@ -172,14 +175,118 @@ init_record(RecordVar *record, TupleDesc tupdesc, Variable *variable)
 	MemoryContextSwitchTo(oldcxt);
 }
 
+/* Check if any attributes of type UNKNOWNOID are in given tupdesc */
+static int
+is_unknownoid_in_tupdesc(TupleDesc tupdesc)
+{
+	int 	i = 0;
+	for (i = 0; i < tupdesc->natts; i++)
+	{
+		Form_pg_attribute attr = GetTupleDescAttr(tupdesc, i);
+
+		if (attr->atttypid == UNKNOWNOID)
+			return true;
+
+	}
+	return false;
+}
+
+/* Replace all attributes of type UNKNOWNOID to TEXTOID in given tupdesc */
+static void
+coerce_unknown_rewrite_tupdesc(TupleDesc old_tupdesc, TupleDesc *return_tupdesc)
+{
+	int 		i;
+
+	(*return_tupdesc) = CreateTupleDescCopy(old_tupdesc);
+
+	for (i = 0; i < old_tupdesc->natts; i++)
+	{
+		Form_pg_attribute attr = GetTupleDescAttr(old_tupdesc, i);
+
+		if (attr->atttypid == UNKNOWNOID)
+		{
+			FormData_pg_attribute new_attr = *attr;
+
+			new_attr.atttypid = TEXTOID;
+			new_attr.attlen = -1;
+			new_attr.atttypmod = -1;
+			memcpy(TupleDescAttr((*return_tupdesc), i), &new_attr, sizeof(FormData_pg_attribute));
+		}
+	}
+}
+
+/*
+ * Deform tuple with old_tupdesc, coerce values of type UNKNOWNOID to TEXTOID, form tuple with new_tupdesc.
+ * new_tupdesc must have the same attributes as old_tupdesc except such of types UNKNOWNOID -- they must be of TEXTOID type
+ */
+static void
+reconstruct_tuple(TupleDesc old_tupdesc, TupleDesc new_tupdesc, HeapTupleHeader *rec)
+{
+	HeapTupleData tuple;
+	HeapTuple	newtup;
+	Datum 	   *values = (Datum*)palloc(old_tupdesc->natts * sizeof(Datum));
+	bool	   *isnull = (bool*)palloc(old_tupdesc->natts * sizeof(bool));
+	Oid			baseTypeId = UNKNOWNOID;
+	int32		baseTypeMod = -1;
+	int32		inputTypeMod = -1;
+	Type		baseType = NULL;
+	int 		i;
+
+	baseTypeId = getBaseTypeAndTypmod(TEXTOID, &baseTypeMod);
+	baseType = typeidType(baseTypeId);
+	/* Build a temporary HeapTuple control structure */
+	tuple.t_len = HeapTupleHeaderGetDatumLength(*rec);
+	tuple.t_data = *rec;
+	heap_deform_tuple(&tuple, old_tupdesc, values, isnull);
+
+	for (i = 0; i < old_tupdesc->natts; i++)
+	{
+		Form_pg_attribute attr = GetTupleDescAttr(old_tupdesc, i);
+
+		if (attr->atttypid == UNKNOWNOID)
+		{
+			values[i] = stringTypeDatum(baseType,
+										DatumGetCString(values[i]),
+										inputTypeMod);
+		}
+	}
+
+	newtup = heap_form_tuple(new_tupdesc, values, isnull);
+	(*rec) = newtup->t_data;
+	pfree(isnull);
+	pfree(values);
+	ReleaseSysCache(baseType);
+}
+
+/*
+ * Used in pg_variables.c insert_record for coercing types in first record in variable.
+ * If there are UNKNOWNOIDs in tupdesc, rewrites it and reconstructs tuple with new tupdesc.
+ * Replaces given tupdesc with the new one.
+ */
+void
+coerce_unknown_first_record(TupleDesc *tupdesc, HeapTupleHeader *rec)
+{
+	TupleDesc	new_tupdesc = NULL;
+
+	if (!is_unknownoid_in_tupdesc(*tupdesc))
+		return;
+
+	coerce_unknown_rewrite_tupdesc(*tupdesc, &new_tupdesc);
+	reconstruct_tuple(*tupdesc, new_tupdesc, rec);
+
+	ReleaseTupleDesc(*tupdesc);
+	(*tupdesc) = new_tupdesc;
+}
+
 /*
  * New record structure should be the same as the first record.
  */
 void
-check_attributes(Variable *variable, TupleDesc tupdesc)
+check_attributes(Variable *variable, HeapTupleHeader *rec, TupleDesc tupdesc)
 {
 	int			i;
 	RecordVar  *record;
+	bool		unknowns = false;
 
 	Assert(variable->typid == RECORDOID);
 
@@ -198,6 +305,16 @@ check_attributes(Variable *variable, TupleDesc tupdesc)
 		Form_pg_attribute attr1 = GetTupleDescAttr(record->tupdesc, i),
 					attr2 = GetTupleDescAttr(tupdesc, i);
 
+		/*
+		 * For the sake of convenience, we consider all the unknown types are to be
+		 * a text type.
+		 */
+		if (convert_unknownoid && (attr1->atttypid == TEXTOID) && (attr2->atttypid == UNKNOWNOID))
+		{
+			unknowns = true;
+			continue;
+		}
+
 		if ((attr1->atttypid != attr2->atttypid)
 			|| (attr1->attndims != attr2->attndims)
 			|| (attr1->atttypmod != attr2->atttypmod))
@@ -208,6 +325,9 @@ check_attributes(Variable *variable, TupleDesc tupdesc)
 							i + 1, GetName(variable)),
 					 errhint("You may need explicit type casts.")));
 	}
+
+	if (unknowns)
+		reconstruct_tuple(tupdesc, record->tupdesc, rec);
 }
 
 /*

sql/pg_variables.sql

@@ -222,7 +222,7 @@ COMMIT; -- warning
 RESET client_min_messages;
 
 -- Clean memory after unsuccessful creation of a variable
-SELECT pgv_insert('vars4', 'r1', row('str1', 'str1')); -- fail
+SELECT pgv_insert('vars4', 'r1', row (('str1'::text, 'str1'::text))); -- fail
 SELECT package FROM pgv_stats() WHERE package = 'vars4';
 
 -- Remove package if it is empty
@@ -268,10 +268,18 @@ SELECT pgv_select('vars', 'r1');
 SELECT pgv_insert('vars', 'r1', foo) FROM foo;
 SELECT pgv_select('vars', 'r1');
 
-SELECT pgv_insert('vars', 'r2', row(1, 'str1'));
-SELECT pgv_insert('vars', 'r2', foo) FROM foo;
+SELECT pgv_insert('vars', 'r2', row(1, 'str1')); -- ok, UNKNOWNOID of 'str1' converts to TEXTOID
+SELECT pgv_insert('vars', 'r2', foo) FROM foo; -- ok
 SELECT pgv_select('vars', 'r2');
 
 SELECT pgv_insert('vars', 'r3', row(1, 'str1'::text));
-SELECT pgv_insert('vars', 'r3', foo) FROM foo;
+SELECT pgv_insert('vars', 'r3', foo) FROM foo; -- ok, no conversions
 SELECT pgv_select('vars', 'r3');
+
+SELECT pgv_insert('vars', 'r4', row(1, 2::int));
+SELECT pgv_insert('vars', 'r4', row(0, 'str1')); -- fail, UNKNOWNOID of 'str1' can't be converted to int
+SELECT pgv_select('vars', 'r4');
+
+SELECT pgv_insert('vars', 'r5', foo) FROM foo; -- types: int, text
+SELECT pgv_insert('vars', 'r5', row(1, 'str1')); -- ok, UNKNOWNOID of 'str1' converts to TEXTOID
+SELECT pgv_select('vars', 'r5');

sql/pg_variables_trans.sql

@@ -470,7 +470,7 @@ FROM generate_series(1,5) AS gs(n) WHERE 1.0/(n-3)<>0;
 SELECT pgv_insert('package', 'errs',row(1), true);
 
 -- Variable should not exists in case when error occurs during creation
-SELECT pgv_insert('vars4', 'r1', row('str1', 'str1'));
+SELECT pgv_insert('vars4', 'r1', row (('str1'::text, 'str1'::text)));
 SELECT pgv_select('vars4', 'r1', 0);
 
 -- If variable created and removed in same transaction level,