On Mon, 9 Sep 2024 22:59:34 +0900
Fujii Masao <masao.fu...@oss.nttdata.com> wrote:
>
>
> On 2024/07/02 16:34, Yugo NAGATA wrote:
> > So, I would like to propose to add
> > has_large_object_function for checking if a user has the privilege on a
> > large
> > object.
>
> +1
Thank you for your looking into this!
I've attached a updated patch.
>
> BTW since we already have pg_largeobject, using has_largeobject_privilege
> might
> offer better consistency. However, I'm okay with the current name for now.
> Even after committing the patch, we can rename it if others prefer
> has_largeobject_privilege.
I was also wandering which is better, so I renamed it because it seems at least
one person,
you, have an idea that has_largeobject_privilege might be better. If it is
found that majority
prefer the previous name, I'll get it back.
>
> As for 0001.patch, should we also remove the inclusion of "access/genam.h" and
> "access/htup_details.h" since they're no longer needed?
Removed.
>
> > 0002 adds has_large_object_privilege function.There are three variations
> > whose
> > arguments are combinations of large object OID with user name, user OID, or
> > implicit user (current_user).
>
> As for 0002.patch, as the code in these three functions is mostly the same,
> it might be more efficient to create a common internal function and have
> the three functions call it for simplicity.
I made a new internal function "has_lo_priv_byid" that is called from these
functions.
> Here are other review comments for 0002.patch.
>
> + <row>
> + <entry role="func_table_entry"><para role="func_signature">
> + <indexterm>
> + <primary>has_large_object_privilege</primary>
>
> In the documentation, access privilege inquiry functions are listed
> alphabetically. So, this function's description should come right
> after has_language_privilege.
Fixed.
>
> + * has_large_objec_privilege variants
>
> Typo: s/objec/object
Fixed.
>
> + * The result is a boolean value: true if user has been granted
> + * the indicated privilege or false if not.
>
> The comment should clarify that NULL is returned if the specified
> large object doesn’t exist. For example,
> --------------
> The result is a boolean value: true if user has the indicated
> privilege, false if not, or NULL if object doesn't exist.
> --------------
Fixed.
>
> +convert_large_object_priv_string(text *priv_text)
>
> It would be better to use "priv_type_text" instead of "priv_text"
> for consistency with similar functions.
>
>
> + static const priv_map parameter_priv_map[] = {
> + {"SELECT", ACL_SELECT},
> + {"UPDATE", ACL_UPDATE},
>
> parameter_priv_map should be large_object_priv_map.
Fixed.
> Additionally, the entries for "WITH GRANT OPTION" should be included here.
Fixed.
>
> +-- not-existing user
> +SELECT has_large_object_privilege(-99999, 1001, 'SELECT'); -- false
> + has_large_object_privilege
> +----------------------------
> + t
> +(1 row)
>
>
> The comment states the result should be false, but the actual result is true.
> One of them seems incorrect.
I misunderstood that has_table_privilege always returns false for not-existing
user,
but it was not correct. Actually, it returns true if the privilege is granted
to public.
I removed this check from the test at last because I don't think it is
important.
Regards,
Yugo Nagata
--
Yugo NAGATA <nag...@sraoss.co.jp>
>From 98c2ce7ef1f03aac7a3bbfdc8c1599ea92d253f8 Mon Sep 17 00:00:00 2001
From: Yugo Nagata <nag...@sraoss.co.jp>
Date: Tue, 2 Jul 2024 15:12:17 +0900
Subject: [PATCH v2 2/2] Add has_largeobject_privilege function
This function is for checking whether a user has the privilege on a
large object. There are three variations whose arguments are combinations
of large object OID with user name, user OID, or implicit user (current_user).
It returns NULL if not-existing large object id is specified, and raises an
error if non-existing user name is specified. These behavior is similar
with has_table_privilege.
---
doc/src/sgml/func.sgml | 18 +++
src/backend/utils/adt/acl.c | 140 ++++++++++++++++++++
src/include/catalog/pg_proc.dat | 13 ++
src/test/regress/expected/privileges.out | 162 +++++++++++++++++++++++
src/test/regress/sql/privileges.sql | 42 ++++++
5 files changed, 375 insertions(+)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..57f2e1f29b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -25113,6 +25113,24 @@ SELECT has_function_privilege('joeuser', 'myfunc(int, text)', 'execute');
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>has_largeobject_privilege</primary>
+ </indexterm>
+ <function>has_largeobject_privilege</function> (
+ <optional> <parameter>user</parameter> <type>name</type> or <type>oid</type>, </optional>
+ <parameter>largeobject</parameter> <type>oid</type>,
+ <parameter>privilege</parameter> <type>text</type> )
+ <returnvalue>boolean</returnvalue>
+ </para>
+ <para>
+ Does user have privilege for large object?
+ Allowable privilege types are
+ <literal>SELECT</literal> and <literal>UPDATE</literal>.
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/adt/acl.c b/src/backend/utils/adt/acl.c
index d7b39140b3..775b900712 100644
--- a/src/backend/utils/adt/acl.c
+++ b/src/backend/utils/adt/acl.c
@@ -26,6 +26,7 @@
#include "catalog/pg_foreign_data_wrapper.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_language.h"
+#include "catalog/pg_largeobject.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_tablespace.h"
@@ -39,6 +40,7 @@
#include "lib/bloomfilter.h"
#include "lib/qunique.h"
#include "miscadmin.h"
+#include "storage/large_object.h"
#include "utils/acl.h"
#include "utils/array.h"
#include "utils/builtins.h"
@@ -46,6 +48,7 @@
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
+#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/varlena.h"
@@ -124,6 +127,7 @@ static AclMode convert_tablespace_priv_string(text *priv_type_text);
static Oid convert_type_name(text *typename);
static AclMode convert_type_priv_string(text *priv_type_text);
static AclMode convert_parameter_priv_string(text *priv_text);
+static AclMode convert_largeobject_priv_string(text *priv_text);
static AclMode convert_role_priv_string(text *priv_type_text);
static AclResult pg_role_aclcheck(Oid role_oid, Oid roleid, AclMode mode);
@@ -4669,6 +4673,142 @@ convert_parameter_priv_string(text *priv_text)
return convert_any_priv_string(priv_text, parameter_priv_map);
}
+/*
+ * has_largeobject_privilege variants
+ * These are all named "has_largeobject_privilege" at the SQL level.
+ * They take various combinations of large object OID with
+ * user name, user OID, or implicit user = current_user.
+ *
+ * The result is a boolean value: true if user has the indicated
+ * privilege, false if not, or NULL if object doesn't exist.
+ */
+
+/*
+ * has_lo_priv_byid
+ *
+ * Helper function to check user privileges on a large object given the
+ * role by Oid, large object by id, and privileges as AclMode.
+ */
+static bool
+has_lo_priv_byid(Oid roleid, Oid lobjId, AclMode priv, bool *is_missing)
+{
+ Snapshot snapshot = NULL;
+ AclResult aclresult;
+
+ if (priv & ACL_UPDATE)
+ snapshot = NULL;
+ else
+ snapshot = GetActiveSnapshot();
+
+ if (!LargeObjectExistsWithSnapshot(lobjId, snapshot))
+ {
+ Assert(is_missing != NULL);
+ *is_missing = true;
+ return false;
+ }
+
+ if (lo_compat_privileges)
+ return true;
+
+ aclresult = pg_largeobject_aclcheck_snapshot(lobjId,
+ roleid,
+ priv,
+ snapshot);
+ return aclresult == ACLCHECK_OK;
+}
+
+/*
+ * has_largeobject_privilege_name_id
+ * Check user privileges on a large object given
+ * name username, large object oid, and text priv name.
+ */
+Datum
+has_largeobject_privilege_name_id(PG_FUNCTION_ARGS)
+{
+ Name username = PG_GETARG_NAME(0);
+ Oid roleid = get_role_oid_or_public(NameStr(*username));
+ Oid lobjId = PG_GETARG_OID(1);
+ text *priv_type_text = PG_GETARG_TEXT_PP(2);
+ AclMode mode;
+ bool is_missing = false;
+ bool result;
+
+ mode = convert_largeobject_priv_string(priv_type_text);
+ result = has_lo_priv_byid(roleid, lobjId, mode, &is_missing);
+
+ if (is_missing)
+ PG_RETURN_NULL();
+
+ PG_RETURN_BOOL(result);
+}
+
+/*
+okui chiba * has_largeobject_privilege_id
+ * Check user privileges on a large object given
+ * large object oid, and text priv name.
+ * current_user is assumed
+ */
+Datum
+has_largeobject_privilege_id(PG_FUNCTION_ARGS)
+{
+ Oid lobjId = PG_GETARG_OID(0);
+ Oid roleid = GetUserId();
+ text *priv_type_text = PG_GETARG_TEXT_PP(1);
+ AclMode mode;
+ bool is_missing = false;
+ bool result;
+
+ mode = convert_largeobject_priv_string(priv_type_text);
+ result = has_lo_priv_byid(roleid, lobjId, mode, &is_missing);
+
+ if (is_missing)
+ PG_RETURN_NULL();
+
+ PG_RETURN_BOOL(result);
+}
+
+/*
+ * has_largeobject_privilege_id_id
+ * Check user privileges on a large object given
+ * roleid, large object oid, and text priv name.
+ */
+Datum
+has_largeobject_privilege_id_id(PG_FUNCTION_ARGS)
+{
+ Oid roleid = PG_GETARG_OID(0);
+ Oid lobjId = PG_GETARG_OID(1);
+ text *priv_type_text = PG_GETARG_TEXT_PP(2);
+ AclMode mode;
+ bool is_missing = false;
+ bool result;
+
+ mode = convert_largeobject_priv_string(priv_type_text);
+ result = has_lo_priv_byid(roleid, lobjId, mode, &is_missing);
+
+ if (is_missing)
+ PG_RETURN_NULL();
+
+ PG_RETURN_BOOL(result);
+}
+
+/*
+ * convert_largeobject_priv_string
+ * Convert text string to AclMode value.
+ */
+static AclMode
+convert_largeobject_priv_string(text *priv_type_text)
+{
+ static const priv_map largeobject_priv_map[] = {
+ {"SELECT", ACL_SELECT},
+ {"SELECT WITH GRANT OPTION", ACL_GRANT_OPTION_FOR(ACL_SELECT)},
+ {"UPDATE", ACL_UPDATE},
+ {"UPDATE WITH GRANT OPTION", ACL_GRANT_OPTION_FOR(ACL_UPDATE)},
+ {NULL, 0}
+ };
+
+ return convert_any_priv_string(priv_type_text, largeobject_priv_map);
+}
+
/*
* pg_has_role variants
* These are all named "pg_has_role" at the SQL level.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index ff5436acac..d1da9a8947 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5333,6 +5333,19 @@
prorettype => 'bool', proargtypes => 'oid text',
prosrc => 'has_any_column_privilege_id' },
+{ oid => '4551', descr => 'user privilege on large objct by username, large object oid',
+ proname => 'has_largeobject_privilege', procost => '10', provolatile => 's',
+ prorettype => 'bool', proargtypes => 'name oid text',
+ prosrc => 'has_largeobject_privilege_name_id' },
+{ oid => '4552', descr => 'current privilege on large objct by large object oid',
+ proname => 'has_largeobject_privilege', procost => '10', provolatile => 's',
+ prorettype => 'bool', proargtypes => 'oid text',
+ prosrc => 'has_largeobject_privilege_id' },
+{ oid => '4553', descr => 'user privilege on large objct by user oid, large object oid',
+ proname => 'has_largeobject_privilege', procost => '10', provolatile => 's',
+ prorettype => 'bool', proargtypes => 'oid oid text',
+ prosrc => 'has_largeobject_privilege_id_id' },
+
{ oid => '3355', descr => 'I/O',
proname => 'pg_ndistinct_in', prorettype => 'pg_ndistinct',
proargtypes => 'cstring', prosrc => 'pg_ndistinct_in' },
diff --git a/src/test/regress/expected/privileges.out b/src/test/regress/expected/privileges.out
index fab0cc800f..f0506951da 100644
--- a/src/test/regress/expected/privileges.out
+++ b/src/test/regress/expected/privileges.out
@@ -2077,10 +2077,160 @@ SELECT lo_truncate(lo_open(2001, x'20000'::int), 10);
0
(1 row)
+-- has_largeobject_privilege function
+-- superuser
+\c -
+SELECT has_largeobject_privilege(1001, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1003, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1004, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1001, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1003, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1004, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+-- not-existing large object
+SELECT has_largeobject_privilege(9999, 'SELECT'); -- NULL
+ has_largeobject_privilege
+---------------------------
+
+(1 row)
+
+-- non-superuser
+SET SESSION AUTHORIZATION regress_priv_user2;
+SELECT has_largeobject_privilege(1001, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege(1003, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1004, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1001, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege(1003, 'UPDATE'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege(1004, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1001, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1003, 'SELECT'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1005, 'SELECT');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1005, 'UPDATE'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege('regress_priv_user3', 2001, 'UPDATE');
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
-- compatibility mode in largeobject permission
\c -
SET lo_compat_privileges = false; -- default setting
SET SESSION AUTHORIZATION regress_priv_user4;
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- false
+ has_largeobject_privilege
+---------------------------
+ f
+(1 row)
+
SELECT loread(lo_open(1002, x'40000'::int), 32); -- to be denied
ERROR: permission denied for large object 1002
SELECT lowrite(lo_open(1002, x'20000'::int), 'abcd'); -- to be denied
@@ -2100,6 +2250,18 @@ ERROR: permission denied for function lo_import
\c -
SET lo_compat_privileges = true; -- compatibility mode
SET SESSION AUTHORIZATION regress_priv_user4;
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- true
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- true
+ has_largeobject_privilege
+---------------------------
+ t
+(1 row)
+
SELECT loread(lo_open(1002, x'40000'::int), 32);
loread
--------
diff --git a/src/test/regress/sql/privileges.sql b/src/test/regress/sql/privileges.sql
index ae338e8cc8..b8101ea6fa 100644
--- a/src/test/regress/sql/privileges.sql
+++ b/src/test/regress/sql/privileges.sql
@@ -1328,11 +1328,50 @@ SELECT loread(lo_open(1005, x'40000'::int), 32);
SELECT lo_truncate(lo_open(1005, x'20000'::int), 10); -- to be denied
SELECT lo_truncate(lo_open(2001, x'20000'::int), 10);
+-- has_largeobject_privilege function
+
+-- superuser
+\c -
+SELECT has_largeobject_privilege(1001, 'SELECT');
+SELECT has_largeobject_privilege(1002, 'SELECT');
+SELECT has_largeobject_privilege(1003, 'SELECT');
+SELECT has_largeobject_privilege(1004, 'SELECT');
+
+SELECT has_largeobject_privilege(1001, 'UPDATE');
+SELECT has_largeobject_privilege(1002, 'UPDATE');
+SELECT has_largeobject_privilege(1003, 'UPDATE');
+SELECT has_largeobject_privilege(1004, 'UPDATE');
+
+-- not-existing large object
+SELECT has_largeobject_privilege(9999, 'SELECT'); -- NULL
+
+-- non-superuser
+SET SESSION AUTHORIZATION regress_priv_user2;
+SELECT has_largeobject_privilege(1001, 'SELECT');
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- false
+SELECT has_largeobject_privilege(1003, 'SELECT');
+SELECT has_largeobject_privilege(1004, 'SELECT');
+
+SELECT has_largeobject_privilege(1001, 'UPDATE');
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- false
+SELECT has_largeobject_privilege(1003, 'UPDATE'); -- false
+SELECT has_largeobject_privilege(1004, 'UPDATE');
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1001, 'SELECT');
+SELECT has_largeobject_privilege('regress_priv_user3', 1003, 'SELECT'); -- false
+SELECT has_largeobject_privilege('regress_priv_user3', 1005, 'SELECT');
+
+SELECT has_largeobject_privilege('regress_priv_user3', 1005, 'UPDATE'); -- false
+SELECT has_largeobject_privilege('regress_priv_user3', 2001, 'UPDATE');
+
-- compatibility mode in largeobject permission
\c -
SET lo_compat_privileges = false; -- default setting
SET SESSION AUTHORIZATION regress_priv_user4;
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- false
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- false
+
SELECT loread(lo_open(1002, x'40000'::int), 32); -- to be denied
SELECT lowrite(lo_open(1002, x'20000'::int), 'abcd'); -- to be denied
SELECT lo_truncate(lo_open(1002, x'20000'::int), 10); -- to be denied
@@ -1346,6 +1385,9 @@ SELECT lo_import('/dev/null', 2003); -- to be denied
SET lo_compat_privileges = true; -- compatibility mode
SET SESSION AUTHORIZATION regress_priv_user4;
+SELECT has_largeobject_privilege(1002, 'SELECT'); -- true
+SELECT has_largeobject_privilege(1002, 'UPDATE'); -- true
+
SELECT loread(lo_open(1002, x'40000'::int), 32);
SELECT lowrite(lo_open(1002, x'20000'::int), 'abcd');
SELECT lo_truncate(lo_open(1002, x'20000'::int), 10);
--
2.34.1
>From 13e78ef824618f0ee1d05ca887c2bfc1f23b7bd8 Mon Sep 17 00:00:00 2001
From: Yugo Nagata <nag...@sraoss.co.jp>
Date: Tue, 2 Jul 2024 15:12:09 +0900
Subject: [PATCH v2 1/2] Deduplicate codes of LargeObjectExists and
mvLargeObjectExists
myLargeObjectExists() and LargeObjectExists() share almost same codes
except to whether snapshot can be specified. To deduplicate it,
thie commit renames myLargeObjectExists() to LargeObjectExistsWithSnapshot()
and rewrites LargeObjectExists() to call this internally.
---
src/backend/catalog/pg_largeobject.c | 13 +++++--
src/backend/storage/large_object/inv_api.c | 40 +---------------------
src/include/catalog/pg_largeobject.h | 2 ++
3 files changed, 13 insertions(+), 42 deletions(-)
diff --git a/src/backend/catalog/pg_largeobject.c b/src/backend/catalog/pg_largeobject.c
index e235f7c5e6..5d9fdfbd4c 100644
--- a/src/backend/catalog/pg_largeobject.c
+++ b/src/backend/catalog/pg_largeobject.c
@@ -14,8 +14,6 @@
*/
#include "postgres.h"
-#include "access/genam.h"
-#include "access/htup_details.h"
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/indexing.h"
@@ -153,6 +151,15 @@ LargeObjectDrop(Oid loid)
*/
bool
LargeObjectExists(Oid loid)
+{
+ return LargeObjectExistsWithSnapshot(loid, NULL);
+}
+
+/*
+ * Same as LargeObjectExists(), except snapshot to read with can be specified.
+ */
+bool
+LargeObjectExistsWithSnapshot(Oid loid, Snapshot snapshot)
{
Relation pg_lo_meta;
ScanKeyData skey[1];
@@ -170,7 +177,7 @@ LargeObjectExists(Oid loid)
sd = systable_beginscan(pg_lo_meta,
LargeObjectMetadataOidIndexId, true,
- NULL, 1, skey);
+ snapshot, 1, skey);
tuple = systable_getnext(sd);
if (HeapTupleIsValid(tuple))
diff --git a/src/backend/storage/large_object/inv_api.c b/src/backend/storage/large_object/inv_api.c
index f951083324..afce51c167 100644
--- a/src/backend/storage/large_object/inv_api.c
+++ b/src/backend/storage/large_object/inv_api.c
@@ -41,7 +41,6 @@
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_largeobject.h"
-#include "catalog/pg_largeobject_metadata.h"
#include "libpq/libpq-fs.h"
#include "miscadmin.h"
#include "storage/large_object.h"
@@ -123,43 +122,6 @@ close_lo_relation(bool isCommit)
}
-/*
- * Same as pg_largeobject.c's LargeObjectExists(), except snapshot to
- * read with can be specified.
- */
-static bool
-myLargeObjectExists(Oid loid, Snapshot snapshot)
-{
- Relation pg_lo_meta;
- ScanKeyData skey[1];
- SysScanDesc sd;
- HeapTuple tuple;
- bool retval = false;
-
- ScanKeyInit(&skey[0],
- Anum_pg_largeobject_metadata_oid,
- BTEqualStrategyNumber, F_OIDEQ,
- ObjectIdGetDatum(loid));
-
- pg_lo_meta = table_open(LargeObjectMetadataRelationId,
- AccessShareLock);
-
- sd = systable_beginscan(pg_lo_meta,
- LargeObjectMetadataOidIndexId, true,
- snapshot, 1, skey);
-
- tuple = systable_getnext(sd);
- if (HeapTupleIsValid(tuple))
- retval = true;
-
- systable_endscan(sd);
-
- table_close(pg_lo_meta, AccessShareLock);
-
- return retval;
-}
-
-
/*
* Extract data field from a pg_largeobject tuple, detoasting if needed
* and verifying that the length is sane. Returns data pointer (a bytea *),
@@ -279,7 +241,7 @@ inv_open(Oid lobjId, int flags, MemoryContext mcxt)
snapshot = GetActiveSnapshot();
/* Can't use LargeObjectExists here because we need to specify snapshot */
- if (!myLargeObjectExists(lobjId, snapshot))
+ if (!LargeObjectExistsWithSnapshot(lobjId, snapshot))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("large object %u does not exist", lobjId)));
diff --git a/src/include/catalog/pg_largeobject.h b/src/include/catalog/pg_largeobject.h
index b40c90b749..e684c58ca9 100644
--- a/src/include/catalog/pg_largeobject.h
+++ b/src/include/catalog/pg_largeobject.h
@@ -20,6 +20,7 @@
#include "catalog/genbki.h"
#include "catalog/pg_largeobject_d.h"
+#include "utils/snapshot.h"
/* ----------------
* pg_largeobject definition. cpp turns this into
@@ -49,5 +50,6 @@ DECLARE_UNIQUE_INDEX_PKEY(pg_largeobject_loid_pn_index, 2683, LargeObjectLOidPNI
extern Oid LargeObjectCreate(Oid loid);
extern void LargeObjectDrop(Oid loid);
extern bool LargeObjectExists(Oid loid);
+extern bool LargeObjectExistsWithSnapshot(Oid loid, Snapshot snapshot);
#endif /* PG_LARGEOBJECT_H */
--
2.34.1
