Thank you very much for reviewing this patch. This is very important to improve the GTT.
> 2020年8月3日 下午3:09，movead...@highgo.ca 写道：
>
>
> >Fixed in global_temporary_table_v29-pg13.patch
> >Please check.
>
> 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.
>
> 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)
>
> 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.
>
> 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.
>
> 5. It's a long patch and hard to review, I think it will pretty good if it
> can be
> divided into several subpatches with relatively independent subfunctions.
Thank you for your suggestion, and I am considering doing so, including adding
comments.
Wenjing
>
> Regards,
> Highgo Software (Canada/China/Pakistan)
> URL : www.highgo.ca <http://www.highgo.ca/>
> EMAIL: mailto:movead(dot)li(at)highgo(dot)ca
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