答复: autovacuum can not remove dead tuples

I think we have foud the cause,after we killed the session that state is idle in transation ,dead tuples can be
removed.Iknow that in PG9.6 we can use DISABLE_PAGE_SKIPPING,but 9.5 can`t .
 
But we still don’t know how this idle in transaction session comes.maybe it is produced by DBeaver,we need to have a
test.

     DBID  |dbname| username| program                 | ip address    | begi_time            |state             |Query
     17482 | ela    | ela    |                                     |   2018-04-03 01:00:00 | active            | select
collect_customer_job();
17482 | ela     | ela    | DBeaver 3.7.7 - Main      | xxx.xxx.xx.xxx   |  2018-04-03 08:51:48  | idle in transaction
|SELECT current_database(), current_schema(),session_user
 
17482 | ela     | dbm  DBeaver 3.7.7 - Main      |xxx.xxx.xx.xxx   |   2018-04-03 16:20:02.| idle in transaction  |
SELECTcurrent_database(), current_schema(),session_user
 

-----邮件原件-----
发件人: Sergei Kornilov [mailto:sk@zsrv.org] 
发送时间: 2018年4月3日 22:19
收件人: 石勇虎 <SHIYONGHU651@pingan.com.cn>; pgsql-bugs@postgresql.org
主题: Re: autovacuum can not remove dead tuples

Hello
And an additional question:

> [postgres:5543@ela] [04-03.17:27:09]=# select 
> pid,state,substr(query,0,100) from pg_stat_activity where query ~ 
> 'ela_elifeassist_product' ;
Have you another long transactions related not to this table?
Any long transaction will prevent vacuum. Vacuum can only delete rows older than the oldest transaction regardless
relations.For example, transaction begin; select * from tablename1;
 
-- sleep 10 min
select * from another_tablename;
commit;
We must leave some dead rows in another_tablename for this 10 minutes because we do not know which rows are required in
anopen transaction later.
 

regards Sergei.


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