>I find this is the most latest mail with an attachment, so I test and reply on
>this thread, several points as below:
>1. I notice it produces new relfilenode when new session login and some
>data insert. But the relfilenode column in pg_class still the one when create
>the global temp table. I think you can try to show 0 in this area as what nail
>relation does.
>I think getting the GTT to have a default relfilenode looks closer to the
>existing implementation, and setting it to 0 requires extra work and has no
>clear benefit.
>What do you think？
>I'd like to know the reasons for your suggestion.
The 'relfilenode' mean the file no on disk which different from oid of a
relation,
the default one is a wrong for gtt, so I think it's not so good to show it in
pg_class.
>2. The nail relations handle their relfilenodes by RelMapFile struct, and this
>patch use hash entry and relfilenode_list, maybe RelMapFile approach more
>understandable in my opinion. Sorry if I miss the real design for that.
>We can see the STORAGE and statistics info for the GTT, including relfilenode,
>through view pg_gtt_relstats
postgres=# \d gtt
Table "public.gtt"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+---------
a | integer | | |
b | integer | | |
postgres=# insert into gtt values(1,1);
INSERT 0 1
postgres=# select * from pg_gtt_relstats ;
schemaname | tablename | relfilenode | relpages | reltuples | relallvisible |
relfrozenxid | relminmxid
------------+-----------+-------------+----------+-----------+---------------+--------------+------------
public | gtt | 16384 | 0 | 0 | 0 |
532 | 1
(1 row)
postgres=# truncate gtt;
TRUNCATE TABLE
postgres=# select * from pg_gtt_relstats ;
schemaname | tablename | relfilenode | relpages | reltuples | relallvisible |
relfrozenxid | relminmxid
------------+-----------+-------------+----------+-----------+---------------+--------------+------------
public | gtt | 16387 | 0 | 0 | 0 |
533 | 1
(1 row)
I just suggest a way which maybe most naturely to the exist code struct, and
it's
uo to you.
>3. I get a wrong result of pg_relation_filepath() function for global temp
>table,
>I think it's necessaryto keep this an correct output.
postgres=# select pg_relation_filepath(oid) from pg_class where relname = 'gtt';
pg_relation_filepath
----------------------
base/13835/t3_16384
(1 row)
I didn't find anything wrong. Could you please give me a demo.
In my opinoin it should show 'base/13835/t3_16387', other than
'base/13835/t3_16384',
because the relfilenode change to 16387 when you truncate it in step 2.
>4. In gtt_search_by_relid() function, it has not handle the missing_ok argument
>if gtt_storage_local_hash is null. There should be some comments if it's the
>right
>code.
>This is a problem that has been fixed in global_temporary_table_v34-pg13.patch.
Sorry about it, I can not find it in mail thread and maybe I miss something.
The mail thread
is so long, it's better to create a new mail thread I think.
Regards,
Highgo Software (Canada/China/Pakistan)
URL : www.highgo.ca
EMAIL: mailto:movead(dot)li(at)highgo(dot)ca
