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Tighten integrity checks on ALTER TABLE ... ALTER COLUMN ... RENAME.

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When a column is renamed, we recursively rename the same column in
all descendent tables.  But if one of those tables also inherits that
column from a table outside the inheritance hierarchy rooted at the
named table, we must throw an error.  The previous coding correctly
prohibited the rename when the parent had inherited the column from
elsewhere, but overlooked the case where the parent was OK but a child
table also inherited the same column from a second, unrelated parent.

For now, not backpatched due to lack of complaints from the field.

KaiGai Kohei, with further changes by me.
Reviewed by Bernd Helme and Tom Lane.
This commit is contained in:
Robert Haas
2010-02-01 19:28:56 +00:00
parent 1526d4e38f
commit 63f9282f6e
9 changed files with 211 additions and 29 deletions
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44
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.320 2010/01/28 23:21:11 petere Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.321 2010/02/01 19:28:56 rhaas Exp $
*
*-------------------------------------------------------------------------
*/
@ -824,7 +824,7 @@ ExecuteTruncate(TruncateStmt *stmt)
ListCell *child;
List *children;
children = find_all_inheritors(myrelid, AccessExclusiveLock);
children = find_all_inheritors(myrelid, AccessExclusiveLock, NULL);
foreach(child, children)
{
@ -1943,7 +1943,7 @@ renameatt(Oid myrelid,
const char *oldattname,
const char *newattname,
bool recurse,
bool recursing)
int expected_parents)
{
Relation targetrelation;
Relation attrelation;
@ -1987,24 +1987,31 @@ renameatt(Oid myrelid,
*/
if (recurse)
{
ListCell *child;
List *children;
List *child_oids, *child_numparents;
ListCell *lo, *li;
children = find_all_inheritors(myrelid, AccessExclusiveLock);
/*
* we need the number of parents for each child so that the recursive
* calls to renameatt() can determine whether there are any parents
* outside the inheritance hierarchy being processed.
*/
child_oids = find_all_inheritors(myrelid, AccessExclusiveLock,
&child_numparents);
/*
* find_all_inheritors does the recursive search of the inheritance
* hierarchy, so all we have to do is process all of the relids in the
* list that it returns.
*/
foreach(child, children)
forboth(lo, child_oids, li, child_numparents)
{
Oid childrelid = lfirst_oid(child);
Oid childrelid = lfirst_oid(lo);
int numparents = lfirst_int(li);
if (childrelid == myrelid)
continue;
/* note we need not recurse again */
renameatt(childrelid, oldattname, newattname, false, true);
renameatt(childrelid, oldattname, newattname, false, numparents);
}
}
else
@ -2012,8 +2019,10 @@ renameatt(Oid myrelid,
/*
* If we are told not to recurse, there had better not be any child
* tables; else the rename would put them out of step.
*
* expected_parents will only be 0 if we are not already recursing.
*/
if (!recursing &&
if (expected_parents == 0 &&
find_inheritance_children(myrelid, NoLock) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
@ -2039,10 +2048,15 @@ renameatt(Oid myrelid,
oldattname)));
/*
* if the attribute is inherited, forbid the renaming, unless we are
* already inside a recursive rename.
* if the attribute is inherited, forbid the renaming. if this is a
* top-level call to renameatt(), then expected_parents will be 0, so the
* effect of this code will be to prohibit the renaming if the attribute
* is inherited at all. if this is a recursive call to renameatt(),
* expected_parents will be the number of parents the current relation has
* within the inheritance hierarchy being processed, so we'll prohibit
* the renaming only if there are additional parents from elsewhere.
*/
if (attform->attinhcount > 0 && !recursing)
if (attform->attinhcount > expected_parents)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot rename inherited column \"%s\"",
@ -3410,7 +3424,7 @@ ATSimpleRecursion(List **wqueue, Relation rel,
ListCell *child;
List *children;
children = find_all_inheritors(relid, AccessExclusiveLock);
children = find_all_inheritors(relid, AccessExclusiveLock, NULL);
/*
* find_all_inheritors does the recursive search of the inheritance
@ -7233,7 +7247,7 @@ ATExecAddInherit(Relation child_rel, RangeVar *parent)
* We use weakest lock we can on child's children, namely AccessShareLock.
*/
children = find_all_inheritors(RelationGetRelid(child_rel),
AccessShareLock);
AccessShareLock, NULL);
if (list_member_oid(children, RelationGetRelid(parent_rel)))
ereport(ERROR,