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Don't set a fast default for anything but a plain table 

The fast default code added in Release 11 omitted to check that the
table a fast default was being added to was a plain table. Thus one
could be added to a foreign table, which predicably blows up. Here we
perform that check.

In addition, on the back branches, since some of these might have
escaped into the wild, if we encounter a missing value for
an attribute of something other than a plain table we ignore it.

Fixes bug #17056

Backpatch to release 11,

Reviewed by: Andres Freund, Álvaro Herrera and Tom Lane
This commit is contained in:
Andrew Dunstan 2021-06-18 06:51:12 -04:00
parent 981524d2e3
commit 0a4efdc7eb
No known key found for this signature in database
GPG Key ID: 99FA7FCB59FC3B81
3 changed files with 42 additions and 1 deletions
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10
src/backend/catalog/heap.c
View File

@ -2161,6 +2161,13 @@ SetAttrMissing(Oid relid, char *attname, char *value)
/* lock the table the attribute belongs to */
tablerel = table_open(relid, AccessExclusiveLock);
/* Don't do anything unless it's a plain table */
if (tablerel->rd_rel->relkind != RELKIND_RELATION)
{
table_close(tablerel, AccessExclusiveLock);
return;
}
/* Lock the attribute row and get the data */
attrrel = table_open(AttributeRelationId, RowExclusiveLock);
atttup = SearchSysCacheAttName(relid, attname);
@ -2287,7 +2294,8 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
valuesAtt[Anum_pg_attribute_atthasdef - 1] = true;
replacesAtt[Anum_pg_attribute_atthasdef - 1] = true;
if (add_column_mode && !attgenerated)
if (rel->rd_rel->relkind == RELKIND_RELATION && add_column_mode &&
!attgenerated)
{
expr2 = expression_planner(expr2);
estate = CreateExecutorState();

19
src/test/regress/expected/fast_default.out
View File

@ -797,7 +797,26 @@ SELECT * FROM t WHERE a IS NULL;
(1 row)
ROLLBACK;
-- verify that a default set on a non-plain table doesn't set a missing
-- value on the attribute
CREATE FOREIGN DATA WRAPPER dummy;
CREATE SERVER s0 FOREIGN DATA WRAPPER dummy;
CREATE FOREIGN TABLE ft1 (c1 integer NOT NULL) SERVER s0;
ALTER FOREIGN TABLE ft1 ADD COLUMN c8 integer DEFAULT 0;
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE char(10);
SELECT count(*)
FROM pg_attribute
WHERE attrelid = 'ft1'::regclass AND
(attmissingval IS NOT NULL OR atthasmissing);
count
-------
0
(1 row)
-- cleanup
DROP FOREIGN TABLE ft1;
DROP SERVER s0;
DROP FOREIGN DATA WRAPPER dummy;
DROP TABLE vtype;
DROP TABLE vtype2;
DROP TABLE follower;

14
src/test/regress/sql/fast_default.sql
View File

@ -524,8 +524,22 @@ SET LOCAL enable_seqscan = false;
SELECT * FROM t WHERE a IS NULL;
ROLLBACK;
-- verify that a default set on a non-plain table doesn't set a missing
-- value on the attribute
CREATE FOREIGN DATA WRAPPER dummy;
CREATE SERVER s0 FOREIGN DATA WRAPPER dummy;
CREATE FOREIGN TABLE ft1 (c1 integer NOT NULL) SERVER s0;
ALTER FOREIGN TABLE ft1 ADD COLUMN c8 integer DEFAULT 0;
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE char(10);
SELECT count(*)
FROM pg_attribute
WHERE attrelid = 'ft1'::regclass AND
(attmissingval IS NOT NULL OR atthasmissing);
-- cleanup
DROP FOREIGN TABLE ft1;
DROP SERVER s0;
DROP FOREIGN DATA WRAPPER dummy;
DROP TABLE vtype;
DROP TABLE vtype2;
DROP TABLE follower;