From a06e41deebdf74b8b5109329dc75b2e9d9057962 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 26 Jan 2011 06:23:23 -0500
Subject: [PATCH] Remove arbitrary ALTER TABLE .. ADD COLUMN restriction.
The previous coding prevented ALTER TABLE .. ADD COLUMN from being used
with a non-NULL default in situations where the table's rowtype was being
used elsewhere. But this is a completely arbitrary restriction since
you could do the same operation in multiple steps (add the column, add
the default, update the table).
Inspired by a patch from Noah Misch, though I didn't use his code.
---
src/backend/commands/tablecmds.c | 8 +++++---
src/test/regress/expected/rowtypes.out | 9 ++++++---
src/test/regress/sql/rowtypes.sql | 8 ++++++--
3 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6726ca97331..8a281968ad8 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -142,6 +142,7 @@ typedef struct AlteredTableInfo
List *newvals; /* List of NewColumnValue */
bool new_notnull; /* T if we added new NOT NULL constraints */
bool new_changeoids; /* T if we added/dropped the OID column */
+ bool new_changetypes; /* T if we changed column types */
Oid newTableSpace; /* new tablespace; 0 means no change */
/* Objects to rebuild after completing ALTER TYPE operations */
List *changedConstraintOids; /* OIDs of constraints to rebuild */
@@ -3378,14 +3379,14 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
}
/*
- * If we need to rewrite the table, the operation has to be propagated to
- * tables that use this table's rowtype as a column type.
+ * If we change column data types or add/remove OIDs, the operation has to
+ * be propagated to tables that use this table's rowtype as a column type.
*
* (Eventually this will probably become true for scans as well, but at
* the moment a composite type does not enforce any constraints, so it's
* not necessary/appropriate to enforce them just during ALTER.)
*/
- if (newrel)
+ if (tab->new_changetypes || tab->new_changeoids)
find_composite_type_dependencies(oldrel->rd_rel->reltype,
RelationGetRelationName(oldrel),
NULL);
@@ -6429,6 +6430,7 @@ ATPrepAlterColumnType(List **wqueue,
newval->expr = (Expr *) transform;
tab->newvals = lappend(tab->newvals, newval);
+ tab->new_changetypes = true;
}
else if (tab->relkind == RELKIND_FOREIGN_TABLE)
{
diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index e5cd71421c6..3d5f4d6c95b 100644
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -82,11 +82,14 @@ select * from people;
(Joe,Blow) | 01-10-1984
(1 row)
--- at the moment this will not work due to ALTER TABLE inadequacy:
+-- the default doesn't need to propagate through to the rowtypes, so this is OK
alter table fullname add column suffix text default '';
-ERROR: cannot alter table "fullname" because column "people"."fn" uses its rowtype
--- but this should work:
+alter table fullname drop column suffix;
+-- this one, without a default, is OK too
alter table fullname add column suffix text default null;
+-- but this should fail, due to ALTER TABLE inadequacy
+alter table fullname alter column suffix set data type integer using null;
+ERROR: cannot alter table "fullname" because column "people"."fn" uses its rowtype
select * from people;
fn | bd
-------------+------------
diff --git a/src/test/regress/sql/rowtypes.sql b/src/test/regress/sql/rowtypes.sql
index 9041df147fe..257213d969e 100644
--- a/src/test/regress/sql/rowtypes.sql
+++ b/src/test/regress/sql/rowtypes.sql
@@ -45,12 +45,16 @@ insert into people values ('(Joe,Blow)', '1984-01-10');
select * from people;
--- at the moment this will not work due to ALTER TABLE inadequacy:
+-- the default doesn't need to propagate through to the rowtypes, so this is OK
alter table fullname add column suffix text default '';
+alter table fullname drop column suffix;
--- but this should work:
+-- this one, without a default, is OK too
alter table fullname add column suffix text default null;
+-- but this should fail, due to ALTER TABLE inadequacy
+alter table fullname alter column suffix set data type integer using null;
+
select * from people;
-- test insertion/updating of subfields
--
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