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.

(cherry picked from commit 0b81f68def)

src/backend/columnar/columnar_metadata.c

@@ -1501,6 +1501,9 @@ 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)
@@ -1517,19 +1520,16 @@ 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;
@@ -1548,8 +1548,12 @@ 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

@@ -2350,8 +2350,13 @@ 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;