pg_sequences bug ?

Started by Shinoda, Noriyoshialmost 9 years ago3 messages
#1Shinoda, Noriyoshi
noriyoshi.shinoda@hpe.com

Hi hackers,

I tried a committed pg_sequences for PostgreSQL 10dev (https://commitfest.postgresql.org/12/771/).
I found that when multiple users create SEQUENCE, I cannot see the pg_sequences catalog. I think that should work just like pg_tables.

$ psql -U user1
postgres=> CREATE SEQUENCE seq1 ;
CREATE SEQUENCE

$ psql -U user2
postgres=> CREATE SEQUENCE seq2 ;
CREATE SEQUENCE
postgres=> SELECT * FROM pg_sequences ;
ERROR: permission denied for sequence seq1

Apparently it seems that the pg_sequence_last_value function included in the pg_sequences view definition cannot be executed.
Is this behavior supposed?

Snapshot:
https://ftp.postgresql.org/pub/snapshot/dev/postgresql-snapshot.tar.gz 2017-02-04 00:29:04
Operating System:
Red Hat Enterprise Linux 7 Update 2 (x86-64)

Regards.

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#2Michael Paquier
michael.paquier@gmail.com
In reply to: Shinoda, Noriyoshi (#1)
1 attachment(s)
Re: pg_sequences bug ?

On Sat, Feb 4, 2017 at 2:50 PM, Shinoda, Noriyoshi
<noriyoshi.shinoda@hpe.com> wrote:

I tried a committed pg_sequences for PostgreSQL 10dev (https://commitfest.postgresql.org/12/771/).
I found that when multiple users create SEQUENCE, I cannot see the pg_sequences catalog. I think that should work just like pg_tables.

$ psql -U user1
postgres=> CREATE SEQUENCE seq1 ;
CREATE SEQUENCE

$ psql -U user2
postgres=> CREATE SEQUENCE seq2 ;
CREATE SEQUENCE
postgres=> SELECT * FROM pg_sequences ;
ERROR: permission denied for sequence seq1

Apparently it seems that the pg_sequence_last_value function included in the pg_sequences view definition cannot be executed.
Is this behavior supposed?

That seems user-unfriendly to me.

We could perhaps just use has_sequence_privilege() and return NULL if
the caller of pg_sequences does not have select and usage access to a
given sequence? Please see the patch attached.
--
Michael

Attachments:

pgsequences-read.patchtext/x-patch; charset=US-ASCII; name=pgsequences-read.patchDownload
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 28be27a07e..907e0fb630 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -175,7 +175,11 @@ CREATE OR REPLACE VIEW pg_sequences AS
         S.seqincrement AS increment_by,
         S.seqcycle AS cycle,
         S.seqcache AS cache_size,
-        pg_sequence_last_value(C.oid) AS last_value
+        CASE
+            WHEN has_sequence_privilege(C.oid, 'SELECT,USAGE'::text)
+                THEN pg_sequence_last_value(C.oid)
+            ELSE NULL
+        END AS last_value
     FROM pg_sequence S JOIN pg_class C ON (C.oid = S.seqrelid)
          LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
     WHERE NOT pg_is_other_temp_schema(N.oid)
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index de5ae00970..d7a165eb42 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1647,7 +1647,10 @@ pg_sequences| SELECT n.nspname AS schemaname,
     s.seqincrement AS increment_by,
     s.seqcycle AS cycle,
     s.seqcache AS cache_size,
-    pg_sequence_last_value((c.oid)::regclass) AS last_value
+        CASE
+            WHEN has_sequence_privilege(c.oid, 'SELECT,USAGE'::text) THEN pg_sequence_last_value((c.oid)::regclass)
+            ELSE NULL::bigint
+        END AS last_value
    FROM ((pg_sequence s
      JOIN pg_class c ON ((c.oid = s.seqrelid)))
      LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace)))
#3Peter Eisentraut
peter.eisentraut@2ndquadrant.com
In reply to: Michael Paquier (#2)
Re: pg_sequences bug ?

On 2/4/17 7:30 AM, Michael Paquier wrote:

We could perhaps just use has_sequence_privilege() and return NULL if
the caller of pg_sequences does not have select and usage access to a
given sequence? Please see the patch attached.

Committed with documentation updates. Thanks.

--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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