Use memcpy instead of memcpy_s to avoid pointless limits in columnar (#6419)

DESCRIPTION: Raises memory limits in columnar from 256MB to 1GB for
reads and writes

This doesn't completely fix #5918 but at least increases the
buffer limits that might cause throwing an error when reading
from or writing into into columnar storage. A way better approach
to fix this is documented in #6420.

Replacing memcpy_s with memcpy is quite safe in those places
since we anyway make sure to allocate enough amount of memory
before writing into related buffers.

src/backend/columnar/columnar_metadata.c

@@ -1650,6 +1650,9 @@ create_estate_for_relation(Relation rel)
 
 /*
  * DatumToBytea serializes a datum into a bytea value.
+ *
+ * Since we don't want to limit datum size to RSIZE_MAX unnecessarily,
+ * we use memcpy instead of memcpy_s several places in this function.
  */
 static bytea *
 DatumToBytea(Datum value, Form_pg_attribute attrForm)
@@ -1666,19 +1669,16 @@ DatumToBytea(Datum value, Form_pg_attribute attrForm)
 			Datum tmp;
 			store_att_byval(&tmp, value, attrForm->attlen);
 
-			memcpy_s(VARDATA(result), datumLength + VARHDRSZ,
-					 &tmp, attrForm->attlen);
+			memcpy(VARDATA(result), &tmp, attrForm->attlen); /* IGNORE-BANNED */
 		}
 		else
 		{
-			memcpy_s(VARDATA(result), datumLength + VARHDRSZ,
-					 DatumGetPointer(value), attrForm->attlen);
+			memcpy(VARDATA(result), DatumGetPointer(value), attrForm->attlen); /* IGNORE-BANNED */
 		}
 	}
 	else
 	{
-		memcpy_s(VARDATA(result), datumLength + VARHDRSZ,
-				 DatumGetPointer(value), datumLength);
+		memcpy(VARDATA(result), DatumGetPointer(value), datumLength); /* IGNORE-BANNED */
 	}
 
 	return result;
@@ -1697,8 +1697,12 @@ ByteaToDatum(bytea *bytes, Form_pg_attribute attrForm)
 	 * after the byteaDatum is freed.
 	 */
 	char *binaryDataCopy = palloc0(VARSIZE_ANY_EXHDR(bytes));
-	memcpy_s(binaryDataCopy, VARSIZE_ANY_EXHDR(bytes),
-			 VARDATA_ANY(bytes), VARSIZE_ANY_EXHDR(bytes));
+
+	/*
+	 * We use IGNORE-BANNED here since we don't want to limit datum size to
+	 * RSIZE_MAX unnecessarily.
+	 */
+	memcpy(binaryDataCopy, VARDATA_ANY(bytes), VARSIZE_ANY_EXHDR(bytes)); /* IGNORE-BANNED */
 
 	return fetch_att(binaryDataCopy, attrForm->attbyval, attrForm->attlen);
 }

src/backend/columnar/columnar_tableam.c

@@ -2576,8 +2576,13 @@ detoast_values(TupleDesc tupleDesc, Datum *orig_values, bool *isnull)
 			if (values == orig_values)
 			{
 				values = palloc(sizeof(Datum) * natts);
-				memcpy_s(values, sizeof(Datum) * natts,
-						 orig_values, sizeof(Datum) * natts);
+
+				/*
+				 * We use IGNORE-BANNED here since we don't want to limit
+				 * size of the buffer that holds the datum array to RSIZE_MAX
+				 * unnecessarily.
+				 */
+				memcpy(values, orig_values, sizeof(Datum) * natts); /* IGNORE-BANNED */
 			}
 
 			/* will be freed when per-tuple context is reset */

src/backend/columnar/columnar_writer.c

@@ -531,6 +531,9 @@ SerializeBoolArray(bool *boolArray, uint32 boolArrayLength)
 /*
  * SerializeSingleDatum serializes the given datum value and appends it to the
  * provided string info buffer.
+ *
+ * Since we don't want to limit datum buffer size to RSIZE_MAX unnecessarily,
+ * we use memcpy instead of memcpy_s several places in this function.
  */
 static void
 SerializeSingleDatum(StringInfo datumBuffer, Datum datum, bool datumTypeByValue,
@@ -552,15 +555,13 @@ SerializeSingleDatum(StringInfo datumBuffer, Datum datum, bool datumTypeByValue,
 		}
 		else
 		{
-			memcpy_s(currentDatumDataPointer, datumBuffer->maxlen - datumBuffer->len,
-					 DatumGetPointer(datum), datumTypeLength);
+			memcpy(currentDatumDataPointer, DatumGetPointer(datum), datumTypeLength); /* IGNORE-BANNED */
 		}
 	}
 	else
 	{
 		Assert(!datumTypeByValue);
-		memcpy_s(currentDatumDataPointer, datumBuffer->maxlen - datumBuffer->len,
-				 DatumGetPointer(datum), datumLength);
+		memcpy(currentDatumDataPointer, DatumGetPointer(datum), datumLength); /* IGNORE-BANNED */
 	}
 
 	datumBuffer->len += datumLengthAligned;
@@ -714,7 +715,12 @@ DatumCopy(Datum datum, bool datumTypeByValue, int datumTypeLength)
 	{
 		uint32 datumLength = att_addlength_datum(0, datumTypeLength, datum);
 		char *datumData = palloc0(datumLength);
-		memcpy_s(datumData, datumLength, DatumGetPointer(datum), datumLength);
+
+		/*
+		 * We use IGNORE-BANNED here since we don't want to limit datum size to
+		 * RSIZE_MAX unnecessarily.
+		 */
+		memcpy(datumData, DatumGetPointer(datum), datumLength); /* IGNORE-BANNED */
 
 		datumCopy = PointerGetDatum(datumData);
 	}
@@ -737,8 +743,12 @@ CopyStringInfo(StringInfo sourceString)
 		targetString->data = palloc0(sourceString->len);
 		targetString->len = sourceString->len;
 		targetString->maxlen = sourceString->len;
-		memcpy_s(targetString->data, sourceString->len,
-				 sourceString->data, sourceString->len);
+
+		/*
+		 * We use IGNORE-BANNED here since we don't want to limit string
+		 * buffer size to RSIZE_MAX unnecessarily.
+		 */
+		memcpy(targetString->data, sourceString->data, sourceString->len); /* IGNORE-BANNED */
 	}
 
 	return targetString;