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* how to clean dropped column in pg_attribute
@ 2020-09-08 09:38 ZongtianHou <zongtianhou@icloud.com>
0 siblings, 1 reply; 3+ messages in thread
From: ZongtianHou @ 2020-09-08 09:38 UTC (permalink / raw)
To: pgsql-admin
Hi, everyone
I found dropped columns still exist in pg_attribute table. In the below example I drop c2 column and vacuum (full) this table and pg_attribute, it still exist (the last row). how can I clean it away?
postgres=# select * from pg_attribute where attrelid=16515;
attrelid | attname | atttypid | attstattarget | attlen | attnum | attndims | attcacheoff | atttypmod | attbyval | attstorage | attalign | attnotnull | atthasdef | attisdropped | attislocal | attinhcount
----------+------------------------------+----------+---------------+--------+--------+----------+-------------+-----------+----------+------------+----------+------------+-----------+--------------+------------+-------------
16515 | c1 | 23 | -1 | 4 | 1 | 0 | -1 | -1 | t | p | i | f | f | f | t | 0
16515 | c3 | 23 | -1 | 4 | 3 | 0 | -1 | -1 | t | p | i | f | f | f | t | 0
16515 | ctid | 27 | 0 | 6 | -1 | 0 | -1 | -1 | f | p | s | t | f | f | t | 0
16515 | xmin | 28 | 0 | 4 | -3 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | cmin | 29 | 0 | 4 | -4 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | xmax | 28 | 0 | 4 | -5 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | cmax | 29 | 0 | 4 | -6 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | tableoid | 26 | 0 | 4 | -7 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | gp_segment_id | 23 | 0 | 4 | -8 | 0 | -1 | -1 | t | p | i | t | f | f | t | 0
16515 | c4 | 16 | -1 | 1 | 4 | 0 | -1 | -1 | t | p | c | f | f | f | t | 0
16515 | ........pg.dropped.2........ | 0 | 0 | 4 | 2 | 0 | -1 | -1 | t | p | i | f | f | t | t | 0
(11 rows)
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: how to clean dropped column in pg_attribute
@ 2020-09-08 09:49 hubert depesz lubaczewski <depesz@depesz.com>
parent: ZongtianHou <zongtianhou@icloud.com>
0 siblings, 1 reply; 3+ messages in thread
From: hubert depesz lubaczewski @ 2020-09-08 09:49 UTC (permalink / raw)
To: ZongtianHou <zongtianhou@icloud.com>; +Cc: pgsql-admin
On Tue, Sep 08, 2020 at 05:38:24PM +0800, ZongtianHou wrote:
> I found dropped columns still exist in pg_attribute table. In the
> below example I drop c2 column and vacuum (full) this table and
> pg_attribute, it still exist (the last row). how can I clean it away?
Unfortunately only by copying the table aside, and then renaming new
table.
But - the dropped attribute will not sure any disk space, as long as you
ran some vacuums.
Best regards,
depesz
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: how to clean dropped column in pg_attribute
@ 2020-09-08 09:51 ZongtianHou <zongtianhou@icloud.com>
parent: hubert depesz lubaczewski <depesz@depesz.com>
0 siblings, 0 replies; 3+ messages in thread
From: ZongtianHou @ 2020-09-08 09:51 UTC (permalink / raw)
To: depesz@depesz.com; +Cc: pgsql-admin
Ok, thanks for this info
Best regards,
Zongtian
> On Sep 8, 2020, at 5:49 PM, hubert depesz lubaczewski <depesz@depesz.com> wrote:
>
> On Tue, Sep 08, 2020 at 05:38:24PM +0800, ZongtianHou wrote:
>> I found dropped columns still exist in pg_attribute table. In the
>> below example I drop c2 column and vacuum (full) this table and
>> pg_attribute, it still exist (the last row). how can I clean it away?
>
> Unfortunately only by copying the table aside, and then renaming new
> table.
>
> But - the dropped attribute will not sure any disk space, as long as you
> ran some vacuums.
>
> Best regards,
>
> depesz
>
^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2020-09-08 09:51 UTC | newest]
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2020-09-08 09:38 how to clean dropped column in pg_attribute ZongtianHou <zongtianhou@icloud.com>
2020-09-08 09:49 ` hubert depesz lubaczewski <depesz@depesz.com>
2020-09-08 09:51 ` ZongtianHou <zongtianhou@icloud.com>
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