Re: [PORTS] Port Bug Report: transaction control interacts strangely with drop table

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: Christopher Oliver <oliver(at)traverse(dot)net>
Cc: pgsql-ports(at)postgreSQL(dot)org
Subject: Re: [PORTS] Port Bug Report: transaction control interacts strangely with drop table
Date: 1999-06-17 03:00:11
Message-ID: 199906170300.XAA09445@candle.pha.pa.us
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We have played with this problem for quite some time. I thought it had
been fixed. Obviously not. You give a good example of the problem.

> PostgreSQL version : 6.5
>
> Compiler used : 2.7.3.2
>
> Hardware:
> ---------
> Pentium 133 / 64M RAM
>
> Versions of other tools:
> ------------------------
>
>
> --------------------------------------------------------------------------
>
> Problem Description:
> --------------------
> Transactions do not protect against outside visibility of
> drop table. The interaction leaves an empty file which
> held the table which prevents a similarly named table
> from being created. Further aborting does not undo
> effects of drop table. This does not seem right.
>
>
>
> --------------------------------------------------------------------------
>
> Test Case:
> ----------
> Scenario:
>
> 1) open two psql sessions (A and B) on the same database.
>
> 2) in session 1, create a talbe an populate with entries.
>
> 3) in session 2, select * from table to see that values
> are present;
>
> 4) in session 1, begin a transaction and drop the
> newly created table.
>
> 5) in session 2, select * from the table. Observe
> that the entries are gone though the transaction is
> not commited.
>
> 6) In session 1, commit the transaction.
>
> 7) In session 2, observe select * still shows an
> empty table where none should exist.
>
> 8) In session 2, observe that while the table doesn't
> exist, you may not create another with the same name.
> (The file representing the table still exists, and it
> is empty.)
>
> Note also that an abort of the transaction will not cause
> the data to return.
>
>
> --------------------------------------------------------------------------
>
> Solution:
> ---------
>
>
> --------------------------------------------------------------------------
>
>
>

--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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