Disallow partition key expressions that return pseudo-types.

This wasn't checked originally, but it should have been, because
in general pseudo-types can't be stored to and retrieved from disk.
Notably, partition bound values of type "record" would not be
interpretable by another session.

In v12 and HEAD, add another flag to CheckAttributeType's repertoire
so that it can produce a specific error message for this case.  That's
infeasible in older branches without an ABI break, so fall back to
a slightly-less-nicely-worded error message in v10 and v11.

Problem noted by Amit Langote, though this patch is not his initial
solution.  Back-patch to v10 where partitioning was introduced.

Discussion: https://postgr.es/m/CA+HiwqFUzjfj9HEsJtYWcr1SgQ_=iCAvQ=O2Sx6aQxoDu4OiHw@mail.gmail.com

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7d034d26415b15ab996b4a998c2bb2134cd629ec..59efa323388fc4ce7e3529584a263882b333dcee 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -13423,6 +13423,16 @@ ComputePartitionAttrs(Relation rel, List *partParams, AttrNumber *partattrs,
                        atttype = exprType(expr);
                        attcollation = exprCollation(expr);
 
+                       /*
+                        * The expression must be of a storable type (e.g., not RECORD).
+                        * The test is the same as for whether a table column is of a safe
+                        * type (which is why we needn't check for the non-expression
+                        * case).
+                        */
+                       CheckAttributeType("partition key",
+                                                          atttype, attcollation,
+                                                          NIL, false);
+
                        /*
                         * Strip any top-level COLLATE clause.  This ensures that we treat
                         * "x COLLATE y" and "(x COLLATE y)" alike.

diff --git a/src/test/regress/expected/create_table.out b/src/test/regress/expected/create_table.out
index 286e39a4989bcbded4011cde019ec372b2704782..56df6e7daa46fd40f2cd46dea59bda1cacbe1f4c 100644 (file)
--- a/src/test/regress/expected/create_table.out
+++ b/src/test/regress/expected/create_table.out
@@ -341,7 +341,7 @@ CREATE TABLE partitioned (
 ERROR:  cannot use subquery in partition key expression
 CREATE TABLE partitioned (
        a int
-) PARTITION BY RANGE (('a'));
+) PARTITION BY RANGE ((42));
 ERROR:  cannot use constant expression as partition key
 CREATE FUNCTION const_func () RETURNS int AS $$ SELECT 1; $$ LANGUAGE SQL IMMUTABLE;
 CREATE TABLE partitioned (
@@ -364,6 +364,17 @@ CREATE TABLE partitioned (
        a int
 ) PARTITION BY RANGE (xmin);
 ERROR:  cannot use system column "xmin" in partition key
+-- cannot use pseudotypes
+CREATE TABLE partitioned (
+       a int,
+       b int
+) PARTITION BY RANGE (((a, b)));
+ERROR:  column "partition key" has pseudo-type record
+CREATE TABLE partitioned (
+       a int,
+       b int
+) PARTITION BY RANGE (a, ('unknown'));
+ERROR:  column "partition key" has pseudo-type unknown
 -- functions in key must be immutable
 CREATE FUNCTION immut_func (a int) RETURNS int AS $$ SELECT a + random()::int; $$ LANGUAGE SQL;
 CREATE TABLE partitioned (

diff --git a/src/test/regress/sql/create_table.sql b/src/test/regress/sql/create_table.sql
index 37bbb657a6a976821797820035504c6e4ef91f71..6edb4bba2a24a8426d7e9e2e1c328b953530e0ce 100644 (file)
--- a/src/test/regress/sql/create_table.sql
+++ b/src/test/regress/sql/create_table.sql
@@ -345,7 +345,7 @@ CREATE TABLE partitioned (
 
 CREATE TABLE partitioned (
        a int
-) PARTITION BY RANGE (('a'));
+) PARTITION BY RANGE ((42));
 
 CREATE FUNCTION const_func () RETURNS int AS $$ SELECT 1; $$ LANGUAGE SQL IMMUTABLE;
 CREATE TABLE partitioned (
@@ -368,6 +368,16 @@ CREATE TABLE partitioned (
        a int
 ) PARTITION BY RANGE (xmin);
 
+-- cannot use pseudotypes
+CREATE TABLE partitioned (
+       a int,
+       b int
+) PARTITION BY RANGE (((a, b)));
+CREATE TABLE partitioned (
+       a int,
+       b int
+) PARTITION BY RANGE (a, ('unknown'));
+
 -- functions in key must be immutable
 CREATE FUNCTION immut_func (a int) RETURNS int AS $$ SELECT a + random()::int; $$ LANGUAGE SQL;
 CREATE TABLE partitioned (