ne 16. 2. 2020 v 16:15 odesílatel 曾文旌(义从) <wenjing....@alibaba-inc.com> napsal:
> > > 2020年2月15日 下午6:06，Pavel Stehule <pavel.steh...@gmail.com> 写道： > > > postgres=# insert into foo select generate_series(1,10000); >> INSERT 0 10000 >> postgres=# \dt+ foo >> List of relations >> ┌────────┬──────┬───────┬───────┬─────────────┬────────┬─────────────┐ >> │ Schema │ Name │ Type │ Owner │ Persistence │ Size │ Description │ >> ╞════════╪══════╪═══════╪═══════╪═════════════╪════════╪═════════════╡ >> │ public │ foo │ table │ pavel │ session │ 384 kB │ │ >> └────────┴──────┴───────┴───────┴─────────────┴────────┴─────────────┘ >> (1 row) >> >> postgres=# truncate foo; >> TRUNCATE TABLE >> postgres=# \dt+ foo >> List of relations >> ┌────────┬──────┬───────┬───────┬─────────────┬───────┬─────────────┐ >> │ Schema │ Name │ Type │ Owner │ Persistence │ Size │ Description │ >> ╞════════╪══════╪═══════╪═══════╪═════════════╪═══════╪═════════════╡ >> │ public │ foo │ table │ pavel │ session │ 16 kB │ │ >> └────────┴──────┴───────┴───────┴─────────────┴───────┴─────────────┘ >> (1 row) >> >> I expect zero size after truncate. >> >> Thanks for review. >> >> I can explain, I don't think it's a bug. >> The current implementation of the truncated GTT retains two blocks of FSM >> pages. >> The same is true for truncating regular tables in subtransactions. >> This is an implementation that truncates the table without changing the >> relfilenode of the table. >> >> > This is not extra important feature - now this is little bit a surprise, > because I was not under transaction. > > Changing relfilenode, I think, is necessary, minimally for future VACUUM > FULL support. > > Not allowing relfilenode changes is the current limit. > I think can improve on it. But ,This is a bit complicated. > so I'd like to know the necessity of this improvement. > Could you give me more details? > I don't think so GTT without support of VACUUM FULL can be accepted. Just due consistency. Regards Pavel > > Regards > > Pavel Stehule > > >> >> Wenjing >> >> >> Regards >> >> Pavel >> >> >>>> >>>> Wenjing >>>> >>>> >>>> >>>> >>>> > >>>> > -- >>>> > Robert Haas >>>> > EnterpriseDB: http://www.enterprisedb.com >>>> > The Enterprise PostgreSQL Company >>>> >>>> >> >
