ATExecAddColumn: resolve FIXME and remove old JIRA references
Unfortunately we can't remove the code referenced by the FIXME yet, but
we've pulled the existing context into the comment and moved to GitHub
for tracking.
[ci skip]
@@ -6618,17 +6618,18 @@ ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
}
/*
- * MPP-14367/MPP-19664 - Handling of default NULL for AO/CO tables.
+ * Handling of default NULL for AO/CO tables.
+ *
* Currently memtuples cannot deal with the scenario where the number of
* attributes in the tuple data don't match the attnum. We will generate an
* explicit NULL default value and force a rewrite of the table below.
- * Note: This is inefficient and there is already another JIRA MPP-5419
- * open to track adding columns without default values to AO tables
- * efficiently. When that JIRA is fixed, the following piece of code may
- * be removed
*
- * GPDB_84_MERGE_FIXME according to Jira 5419 is resolved, can we remove
- * this code now?
+ * At one point there were plans to restructure memtuples so that this
+ * rewrite did not have to occur. An optimization was added to
+ * column-oriented tables to avoid the rewrite, but it does not apply to
+ * row-oriented tables. Eventually it would be nice to remove this
+ * workaround; see GitHub issue
+ * https://github.com/greenplum-db/gpdb/issues/3756
*/
if (!defval && (RelationIsAoRows(rel) || RelationIsAoCols(rel)))
defval = (Expr *) makeNullConst(typeOid, -1);
