Weird behaviour with the new MOVE clause of ALTER TABLESPACE

Hey,

I was working on adding support to the new MOVE clause of the ALTER
TABLESPACE statement to pgAdmin when I noticed this issue. See this
example:

Fresh git compilation, and new database on a new cluster:

$ createdb b1
$ psql b1
psql (9.4devel)
Type "help" for help.

b1=# CREATE TABLESPACE ts1 LOCATION '/opt/postgresql/tablespaces/ts94';
CREATE TABLESPACE
b1=# SELECT count(*) FROM pg_class c
JOIN pg_tablespace t ON c.reltablespace=t.oid
AND spcname='pg_default';
count
-------
0
(1 row)

b1=# SELECT count(*) FROM pg_class c
JOIN pg_tablespace t ON c.reltablespace=t.oid AND spcname='ts1';
count
-------
0
(1 row)

b1=# SELECT count(*) FROM pg_class c WHERE c.reltablespace=0;
count
-------
268
(1 row)

So, 268 objects in the default tablespace (which happens to be
pg_default) and none in ts1 (that's correct, it was just created).

Now, we move all objects from pg_default to ts1. My expectation was that
all user objects would be afterwards in the ts1 tablespace. And here is
what happens:

b1=# ALTER TABLESPACE pg_default MOVE ALL TO ts1;
ALTER TABLESPACE
b1=# SELECT count(*) FROM pg_class c
JOIN pg_tablespace t ON c.reltablespace=t.oid
AND spcname='pg_default';
count
-------
0
(1 row)

b1=# SELECT count(*) FROM pg_class c
JOIN pg_tablespace t ON c.reltablespace=t.oid AND spcname='ts1';
count
-------
21
(1 row)

b1=# SELECT count(*) FROM pg_class c WHERE c.reltablespace=0;
count
-------
247
(1 row)

I have 21 objects in ts1 and 247 stayed in the default tablespace. I'm
not sure what I should find weird: that some objects were moved, or that
not all objects were moved :)

What's weirder is the objects themselves:

b1=# SELECT relkind, relname FROM pg_class c
JOIN pg_tablespace t ON c.reltablespace=t.oid AND spcname='ts1'
ORDER BY 1, 2;
relkind | relname
---------+-------------------------
i | pg_toast_12619_index
i | pg_toast_12624_index
i | pg_toast_12629_index
i | pg_toast_12634_index
i | pg_toast_12639_index
i | pg_toast_12644_index
i | pg_toast_12649_index
r | sql_features
r | sql_implementation_info
r | sql_languages
r | sql_packages
r | sql_parts
r | sql_sizing
r | sql_sizing_profiles
t | pg_toast_12619
t | pg_toast_12624
t | pg_toast_12629
t | pg_toast_12634
t | pg_toast_12639
t | pg_toast_12644
t | pg_toast_12649
(21 rows)

In other words, all information_schema tables (and their toast tables
and the toast indexes) were moved. Why only them? AFAICT, there are no
other information_schema tables, only views which obviously are not
concerned by the ALTER TABLESPACE statement.

Should information_schema tables be moved and not pg_catalog ones? it
doesn't seem consistent to me.

I probably miss something obvious.

Thanks for any pointer.

--
Guillaume
http://blog.guillaume.lelarge.info
http://www.dalibo.com

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