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Re: pgsql/src/backend/commands sequence.c

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: tgl(at)postgresql(dot)org
Cc: pgsql-committers(at)postgresql(dot)org
Subject: Re: pgsql/src/backend/commands sequence.c
Date: 2002-01-11 19:22:34
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-committers
> Log message:
> 	Fix sequence creation to set the t_xmin of a sequence's tuple to
> 	FrozenTransactionId, not the XID of the creating transaction.  Without
> 	this it's possible for a reference to a long-gone CLOG record to occur,
> 	per Christian Meunier's bug report of 10-Jan-02.  Worse, the sequence
> 	tuple would become invisible to SELECTs after 2 billion transactions.

Can you remind me why sequences are different from normal tables in the

> 	Since the fix is applied during sequence creation it does not help
> 	existing databases, unless you drop and recreate every sequence.
> 	However, we intend to force initdb for 7.2RC1 anyway, to fix a pg_proc
> 	error, so I see no need to do more for this problem.

This eliminates allowing an SQL query to fix the problems with pg_proc
--- pg_upgrade, because there was an int4->int8 change in sequences,
will properly set the new XID if it is used on older databases.

  Bruce Momjian                        |
  pgman(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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Subject: pgsql/src/backend/utils/time tqual.c
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