From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
---|---|
To: | 曾文旌 <wenjing(dot)zwj(at)alibaba-inc(dot)com> |
Cc: | Prabhat Sahu <prabhat(dot)sahu(at)enterprisedb(dot)com>, tushar <tushar(dot)ahuja(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, 蔡松露(子嘉) <zijia(at)taobao(dot)com>, "Cai, Le" <le(dot)cai(at)alibaba-inc(dot)com> |
Subject: | Re: [Proposal] Global temporary tables |
Date: | 2020-07-07 10:05:42 |
Message-ID: | CAFj8pRCp+r=WRXryPQ1Lxhq-tfZqomp00FjddUztqWaAOO4Pxg@mail.gmail.com |
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Lists: | pgsql-hackers |
Hi
> GTT Merge the latest PGMaster and resolves conflicts.
>
>
>
I tested it and it looks fine. I think it is very usable in current form,
but still there are some issues:
postgres=# create global temp table foo(a int);
CREATE TABLE
postgres=# insert into foo values(10);
INSERT 0 1
postgres=# alter table foo add column x int;
ALTER TABLE
postgres=# analyze foo;
WARNING: reloid 16400 not support update attstat after add colunm
WARNING: reloid 16400 not support update attstat after add colunm
ANALYZE
Please, can you summarize what is done, what limits are there, what can be
implemented hard, what can be implemented easily?
I found one open question - how can be implemented table locks - because
data is physically separated, then we don't need table locks as protection
against race conditions.
Now, table locks are implemented on a global level. So exclusive lock on
GTT in one session block insertion on the second session. Is it expected
behaviour? It is safe, but maybe it is too strict.
We should define what table lock is meaning on GTT.
Regards
Pavel
> Pavel
>
>
>> With Regards,
>> Prabhat Kumar Sahu
>> EnterpriseDB: http://www.enterprisedb.com
>>
>>
>>
>
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