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mirror of https://github.com/postgres/postgres.git synced 2026-10-23 13:29:09 +03:00

Don't try to re-order the subcommands of CREATE SCHEMA.

transformCreateSchemaStmtElements has always believed that it is
supposed to re-order the subcommands of CREATE SCHEMA into a safe
execution order.  However, it is nowhere near being capable of doing
that correctly.  Nor is there reason to think that it ever will be,
or that that is a well-defined requirement.  (The SQL standard does
say that it should be possible to do foreign-key forward references
within CREATE SCHEMA, but it's not clear that the text requires
anything more than that.)  Moreover, the problem will get worse as
we add more subcommand types.  Let's just drop the whole idea and
execute the commands in the order given, which seems like a much
less astonishment-prone definition anyway.  The foreign-key issue
will be handled in a follow-up patch.

This will result in a release-note-worthy incompatibility,
which is that forward references like
	CREATE SCHEMA myschema
	    CREATE VIEW myview AS SELECT * FROM mytable
	    CREATE TABLE mytable (...);
used to work and no longer will.  Considering how many closely
related variants never worked, this isn't much of a loss.

Along the way, pass down a ParseState so that we can provide an
error cursor for "wrong schema name" and related errors, and fix
transformCreateSchemaStmtElements so that it doesn't scribble
on the parsetree passed to it.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/1075425.1732993688@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2026-04-06 14:42:55 -04:00
parent 1ff3180ca0
commit a9c350d9ee
14 changed files with 139 additions and 112 deletions

View File

@@ -131,6 +131,11 @@ CREATE SCHEMA IF NOT EXISTS AUTHORIZATION <replaceable class="parameter">role_sp
<literal>CREATE</literal> privilege for the current database.
(Of course, superusers bypass this check.)
</para>
<para>
The <replaceable class="parameter">schema_element</replaceable>
subcommands, if any, are executed in the order they are written.
</para>
</refsect1>
<refsect1>
@@ -193,12 +198,12 @@ CREATE VIEW hollywood.winners AS
</para>
<para>
The SQL standard specifies that the subcommands in <command>CREATE
SCHEMA</command> can appear in any order. The present
<productname>PostgreSQL</productname> implementation does not
handle all cases of forward references in subcommands; it might
sometimes be necessary to reorder the subcommands in order to avoid
forward references.
Some other SQL implementations attempt to allow more kinds of forward
references to objects defined in
later <replaceable class="parameter">schema_element</replaceable>
subcommands than just foreign key constraints. This is difficult or
impossible to do correctly in general, and it is not clear that the SQL
standard requires any such behavior except for foreign keys.
</para>
<para>

View File

@@ -1952,14 +1952,17 @@ CreateExtensionInternal(char *extensionName,
if (!OidIsValid(schemaOid))
{
ParseState *pstate = make_parsestate(NULL);
CreateSchemaStmt *csstmt = makeNode(CreateSchemaStmt);
pstate->p_sourcetext = "(generated CREATE SCHEMA command)";
csstmt->schemaname = schemaName;
csstmt->authrole = NULL; /* will be created by current user */
csstmt->schemaElts = NIL;
csstmt->if_not_exists = false;
CreateSchemaCommand(csstmt, "(generated CREATE SCHEMA command)",
-1, -1);
CreateSchemaCommand(pstate, csstmt, -1, -1);
/*
* CreateSchemaCommand includes CommandCounterIncrement, so new

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@@ -49,7 +49,7 @@ static void AlterSchemaOwner_internal(HeapTuple tup, Relation rel, Oid newOwnerI
* a subquery.
*/
Oid
CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString,
CreateSchemaCommand(ParseState *pstate, CreateSchemaStmt *stmt,
int stmt_location, int stmt_len)
{
const char *schemaName = stmt->schemaname;
@@ -189,12 +189,12 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString,
/*
* Examine the list of commands embedded in the CREATE SCHEMA command, and
* reorganize them into a sequentially executable order with no forward
* references. Note that the result is still a list of raw parsetrees ---
* we cannot, in general, run parse analysis on one statement until we
* have actually executed the prior ones.
* do preliminary transformations. Note that the result is still a list
* of raw parsetrees --- we cannot, in general, run parse analysis on one
* statement until we have actually executed the prior ones.
*/
parsetree_list = transformCreateSchemaStmtElements(stmt->schemaElts,
parsetree_list = transformCreateSchemaStmtElements(pstate,
stmt->schemaElts,
schemaName);
/*
@@ -219,7 +219,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt, const char *queryString,
/* do this step */
ProcessUtility(wrapper,
queryString,
pstate->p_sourcetext,
false,
PROCESS_UTILITY_SUBCOMMAND,
NULL,

View File

@@ -99,18 +99,6 @@ typedef struct
bool ofType; /* true if statement contains OF typename */
} CreateStmtContext;
/* State shared by transformCreateSchemaStmtElements and its subroutines */
typedef struct
{
const char *schemaname; /* name of schema */
List *sequences; /* CREATE SEQUENCE items */
List *tables; /* CREATE TABLE items */
List *views; /* CREATE VIEW items */
List *indexes; /* CREATE INDEX items */
List *triggers; /* CREATE TRIGGER items */
List *grants; /* GRANT items */
} CreateSchemaStmtContext;
static void transformColumnDefinition(CreateStmtContext *cxt,
ColumnDef *column);
@@ -137,7 +125,8 @@ static void transformCheckConstraints(CreateStmtContext *cxt,
static void transformConstraintAttrs(CreateStmtContext *cxt,
List *constraintList);
static void transformColumnType(CreateStmtContext *cxt, ColumnDef *column);
static void setSchemaName(const char *context_schema, char **stmt_schema_name);
static void checkSchemaNameRV(ParseState *pstate, const char *context_schema,
RangeVar *relation);
static void transformPartitionCmd(CreateStmtContext *cxt, PartitionBoundSpec *bound);
static List *transformPartitionRangeBounds(ParseState *pstate, List *blist,
Relation parent);
@@ -4395,51 +4384,35 @@ transformColumnType(CreateStmtContext *cxt, ColumnDef *column)
* transformCreateSchemaStmtElements -
* analyzes the elements of a CREATE SCHEMA statement
*
* Split the schema element list from a CREATE SCHEMA statement into
* individual commands and place them in the result list in an order
* such that there are no forward references (e.g. GRANT to a table
* created later in the list). Note that the logic we use for determining
* forward references is presently quite incomplete.
* This is now somewhat vestigial: its only real responsibility is to complain
* if any of the elements are trying to create objects outside the new schema.
* We used to try to re-order the commands in a way that would work even if
* the user-written order would not, but that's too hard (perhaps impossible)
* to do correctly with not-yet-parse-analyzed commands. Now we'll just
* execute the elements in the order given.
*
* "schemaName" is the name of the schema that will be used for the creation
* of the objects listed, that may be compiled from the schema name defined
* of the objects listed. It may be obtained from the schema name defined
* in the statement or a role specification.
*
* SQL also allows constraints to make forward references, so thumb through
* the table columns and move forward references to a posterior alter-table
* command.
*
* The result is a list of parse nodes that still need to be analyzed ---
* but we can't analyze the later commands until we've executed the earlier
* ones, because of possible inter-object references.
*
* Note: this breaks the rules a little bit by modifying schema-name fields
* within passed-in structs. However, the transformation would be the same
* if done over, so it should be all right to scribble on the input to this
* extent.
*/
List *
transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
transformCreateSchemaStmtElements(ParseState *pstate, List *schemaElts,
const char *schemaName)
{
CreateSchemaStmtContext cxt;
List *result;
ListCell *elements;
cxt.schemaname = schemaName;
cxt.sequences = NIL;
cxt.tables = NIL;
cxt.views = NIL;
cxt.indexes = NIL;
cxt.triggers = NIL;
cxt.grants = NIL;
List *elements = NIL;
ListCell *lc;
/*
* Run through each schema element in the schema element list. Separate
* statements by type, and do preliminary analysis.
* Run through each schema element in the schema element list. Check
* target schema names, and collect the list of actions to be done.
*/
foreach(elements, schemaElts)
foreach(lc, schemaElts)
{
Node *element = lfirst(elements);
Node *element = lfirst(lc);
switch (nodeTag(element))
{
@@ -4447,8 +4420,8 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
{
CreateSeqStmt *elp = (CreateSeqStmt *) element;
setSchemaName(cxt.schemaname, &elp->sequence->schemaname);
cxt.sequences = lappend(cxt.sequences, element);
checkSchemaNameRV(pstate, schemaName, elp->sequence);
elements = lappend(elements, element);
}
break;
@@ -4456,12 +4429,8 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
{
CreateStmt *elp = (CreateStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
/*
* XXX todo: deal with constraints
*/
cxt.tables = lappend(cxt.tables, element);
checkSchemaNameRV(pstate, schemaName, elp->relation);
elements = lappend(elements, element);
}
break;
@@ -4469,12 +4438,8 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
{
ViewStmt *elp = (ViewStmt *) element;
setSchemaName(cxt.schemaname, &elp->view->schemaname);
/*
* XXX todo: deal with references between views
*/
cxt.views = lappend(cxt.views, element);
checkSchemaNameRV(pstate, schemaName, elp->view);
elements = lappend(elements, element);
}
break;
@@ -4482,8 +4447,8 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
{
IndexStmt *elp = (IndexStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
cxt.indexes = lappend(cxt.indexes, element);
checkSchemaNameRV(pstate, schemaName, elp->relation);
elements = lappend(elements, element);
}
break;
@@ -4491,13 +4456,13 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
{
CreateTrigStmt *elp = (CreateTrigStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
cxt.triggers = lappend(cxt.triggers, element);
checkSchemaNameRV(pstate, schemaName, elp->relation);
elements = lappend(elements, element);
}
break;
case T_GrantStmt:
cxt.grants = lappend(cxt.grants, element);
elements = lappend(elements, element);
break;
default:
@@ -4506,32 +4471,41 @@ transformCreateSchemaStmtElements(List *schemaElts, const char *schemaName)
}
}
result = NIL;
result = list_concat(result, cxt.sequences);
result = list_concat(result, cxt.tables);
result = list_concat(result, cxt.views);
result = list_concat(result, cxt.indexes);
result = list_concat(result, cxt.triggers);
result = list_concat(result, cxt.grants);
return result;
return elements;
}
/*
* setSchemaName
* Set or check schema name in an element of a CREATE SCHEMA command
* checkSchemaNameRV
* Check schema name in an element of a CREATE SCHEMA command,
* where the element's name is given by a RangeVar
*
* It's okay if the command doesn't specify a target schema name, because
* CreateSchemaCommand will set up the default creation schema to be the
* new schema. But if a target schema name is given, it had better match.
* We also have to check that the command doesn't say CREATE TEMP, since
* that would likewise put the object into the wrong schema.
*/
static void
setSchemaName(const char *context_schema, char **stmt_schema_name)
checkSchemaNameRV(ParseState *pstate, const char *context_schema,
RangeVar *relation)
{
if (*stmt_schema_name == NULL)
*stmt_schema_name = unconstify(char *, context_schema);
else if (strcmp(context_schema, *stmt_schema_name) != 0)
if (relation->schemaname != NULL &&
strcmp(context_schema, relation->schemaname) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_SCHEMA_DEFINITION),
errmsg("CREATE specifies a schema (%s) "
"different from the one being created (%s)",
*stmt_schema_name, context_schema)));
relation->schemaname, context_schema),
parser_errposition(pstate, relation->location)));
if (relation->relpersistence == RELPERSISTENCE_TEMP)
{
/* spell this error the same as in RangeVarAdjustRelationPersistence */
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot create temporary relation in non-temporary schema"),
parser_errposition(pstate, relation->location)));
}
}
/*

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@@ -1122,8 +1122,8 @@ ProcessUtilitySlow(ParseState *pstate,
* relation and attribute manipulation
*/
case T_CreateSchemaStmt:
CreateSchemaCommand((CreateSchemaStmt *) parsetree,
queryString,
CreateSchemaCommand(pstate,
(CreateSchemaStmt *) parsetree,
pstmt->stmt_location,
pstmt->stmt_len);

View File

@@ -16,12 +16,11 @@
#define SCHEMACMDS_H
#include "catalog/objectaddress.h"
#include "nodes/parsenodes.h"
#include "parser/parse_node.h"
extern Oid CreateSchemaCommand(CreateSchemaStmt *stmt,
const char *queryString,
extern Oid CreateSchemaCommand(ParseState *pstate,
CreateSchemaStmt *stmt,
int stmt_location, int stmt_len);
extern ObjectAddress RenameSchema(const char *oldname, const char *newname);
extern ObjectAddress AlterSchemaOwner(const char *name, Oid newOwnerId);
extern void AlterSchemaOwner_oid(Oid schemaoid, Oid newOwnerId);

View File

@@ -30,7 +30,8 @@ extern CreateStatsStmt *transformStatsStmt(Oid relid, CreateStatsStmt *stmt,
const char *queryString);
extern void transformRuleStmt(RuleStmt *stmt, const char *queryString,
List **actions, Node **whereClause);
extern List *transformCreateSchemaStmtElements(List *schemaElts,
extern List *transformCreateSchemaStmtElements(ParseState *pstate,
List *schemaElts,
const char *schemaName);
extern PartitionBoundSpec *transformPartitionBound(ParseState *pstate, Relation parent,
PartitionBoundSpec *spec);

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@@ -9,55 +9,92 @@ CREATE ROLE regress_create_schema_role SUPERUSER;
CREATE SCHEMA AUTHORIZATION regress_create_schema_role
CREATE SEQUENCE schema_not_existing.seq;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE SEQUENCE schema_not_existing.seq;
^
CREATE SCHEMA AUTHORIZATION regress_create_schema_role
CREATE TABLE schema_not_existing.tab (id int);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE TABLE schema_not_existing.tab (id int);
^
CREATE SCHEMA AUTHORIZATION regress_create_schema_role
CREATE VIEW schema_not_existing.view AS SELECT 1;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE VIEW schema_not_existing.view AS SELECT 1;
^
CREATE SCHEMA AUTHORIZATION regress_create_schema_role
CREATE INDEX ON schema_not_existing.tab (id);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE INDEX ON schema_not_existing.tab (id);
^
CREATE SCHEMA AUTHORIZATION regress_create_schema_role
CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_existing.tab
EXECUTE FUNCTION schema_trig.no_func();
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_exi...
^
-- Again, with a role specification and no schema names.
SET ROLE regress_create_schema_role;
CREATE SCHEMA AUTHORIZATION CURRENT_ROLE
CREATE SEQUENCE schema_not_existing.seq;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE SEQUENCE schema_not_existing.seq;
^
CREATE SCHEMA AUTHORIZATION CURRENT_ROLE
CREATE TABLE schema_not_existing.tab (id int);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE TABLE schema_not_existing.tab (id int);
^
CREATE SCHEMA AUTHORIZATION CURRENT_ROLE
CREATE VIEW schema_not_existing.view AS SELECT 1;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE VIEW schema_not_existing.view AS SELECT 1;
^
CREATE SCHEMA AUTHORIZATION CURRENT_ROLE
CREATE INDEX ON schema_not_existing.tab (id);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE INDEX ON schema_not_existing.tab (id);
^
CREATE SCHEMA AUTHORIZATION CURRENT_ROLE
CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_existing.tab
EXECUTE FUNCTION schema_trig.no_func();
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_create_schema_role)
LINE 2: CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_exi...
^
-- Again, with a schema name and a role specification.
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE SEQUENCE schema_not_existing.seq;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_schema_1)
LINE 2: CREATE SEQUENCE schema_not_existing.seq;
^
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE TABLE schema_not_existing.tab (id int);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_schema_1)
LINE 2: CREATE TABLE schema_not_existing.tab (id int);
^
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE VIEW schema_not_existing.view AS SELECT 1;
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_schema_1)
LINE 2: CREATE VIEW schema_not_existing.view AS SELECT 1;
^
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE INDEX ON schema_not_existing.tab (id);
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_schema_1)
LINE 2: CREATE INDEX ON schema_not_existing.tab (id);
^
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_existing.tab
EXECUTE FUNCTION schema_trig.no_func();
ERROR: CREATE specifies a schema (schema_not_existing) different from the one being created (regress_schema_1)
LINE 2: CREATE TRIGGER schema_trig BEFORE INSERT ON schema_not_exi...
^
RESET ROLE;
-- Forward references no longer work in general.
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE VIEW abcd_view AS SELECT a FROM abcd
CREATE TABLE abcd (a int);
ERROR: relation "abcd" does not exist
LINE 2: CREATE VIEW abcd_view AS SELECT a FROM abcd
^
-- Cases where the schema creation succeeds.
-- The schema created matches the role name.
CREATE SCHEMA AUTHORIZATION regress_create_schema_role

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@@ -128,6 +128,8 @@ ERROR: cannot create temporary relation in non-temporary schema
CREATE SCHEMA test_view_schema
CREATE TEMP VIEW testview AS SELECT 1;
ERROR: cannot create temporary relation in non-temporary schema
LINE 2: CREATE TEMP VIEW testview AS SELECT 1;
^
-- joins: if any of the join relations are temporary, the view
-- should also be temporary
-- should be non-temp

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@@ -425,13 +425,13 @@ NOTICE: END: command_tag=CREATE TABLE type=table identity=evttrig.one
NOTICE: END: command_tag=CREATE INDEX type=index identity=evttrig.one_pkey
NOTICE: END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.one_col_a_seq
NOTICE: END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.one_col_c_seq
NOTICE: END: command_tag=CREATE INDEX type=index identity=evttrig.one_idx
NOTICE: END: command_tag=CREATE TABLE type=table identity=evttrig.two
NOTICE: END: command_tag=ALTER TABLE type=table identity=evttrig.two
NOTICE: END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.id_col_d_seq
NOTICE: END: command_tag=CREATE TABLE type=table identity=evttrig.id
NOTICE: END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.id_col_d_seq
NOTICE: END: command_tag=CREATE VIEW type=view identity=evttrig.one_view
NOTICE: END: command_tag=CREATE INDEX type=index identity=evttrig.one_idx
-- View with column additions
CREATE OR REPLACE VIEW evttrig.one_view AS SELECT * FROM evttrig.two, evttrig.id;
NOTICE: END: command_tag=CREATE VIEW type=view identity=evttrig.one_view

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@@ -10,13 +10,14 @@ SELECT pg_catalog.set_config('search_path', ' ', false);
(1 row)
CREATE SCHEMA test_ns_schema_1
CREATE UNIQUE INDEX abc_a_idx ON abc (a)
CREATE VIEW abc_view AS
SELECT a+1 AS a, b+1 AS b FROM abc
CREATE TABLE abc (
a serial,
b int UNIQUE
);
)
CREATE UNIQUE INDEX abc_a_idx ON abc (a)
CREATE VIEW abc_view AS
SELECT a+1 AS a, b+1 AS b FROM abc
;
-- verify that the correct search_path restored on abort
SET search_path to public;
BEGIN;

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@@ -47,6 +47,11 @@ CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
EXECUTE FUNCTION schema_trig.no_func();
RESET ROLE;
-- Forward references no longer work in general.
CREATE SCHEMA regress_schema_1 AUTHORIZATION CURRENT_ROLE
CREATE VIEW abcd_view AS SELECT a FROM abcd
CREATE TABLE abcd (a int);
-- Cases where the schema creation succeeds.
-- The schema created matches the role name.
CREATE SCHEMA AUTHORIZATION regress_create_schema_role

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@@ -7,15 +7,16 @@
SELECT pg_catalog.set_config('search_path', ' ', false);
CREATE SCHEMA test_ns_schema_1
CREATE TABLE abc (
a serial,
b int UNIQUE
)
CREATE UNIQUE INDEX abc_a_idx ON abc (a)
CREATE VIEW abc_view AS
SELECT a+1 AS a, b+1 AS b FROM abc
CREATE TABLE abc (
a serial,
b int UNIQUE
);
;
-- verify that the correct search_path restored on abort
SET search_path to public;

View File

@@ -585,7 +585,6 @@ CreateRangeStmt
CreateReplicationSlotCmd
CreateRoleStmt
CreateSchemaStmt
CreateSchemaStmtContext
CreateSeqStmt
CreateStatsStmt
CreateStmt