Hi, I have started testing the "Global temporary table" feature, from "gtt_v11-pg13.patch". Below is my findings:
-- session 1: postgres=# create global temporary table gtt1(a int); CREATE TABLE -- seeeion 2: postgres=# truncate gtt1 ; ERROR: could not open file "base/13585/t3_16384": No such file or directory is it expected? On Sun, Feb 16, 2020 at 8:53 PM Pavel Stehule <pavel.steh...@gmail.com> wrote: > > > 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 >>>>> >>>>> >>> >> -- With Regards, Prabhat Kumar Sahu EnterpriseDB: http://www.enterprisedb.com
