How does PostgreSQL recognise "deleted" tuples by using xmax ?

Started by 纪晓曦over 16 years ago2 messagesgeneral
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#1纪晓曦
sheepjxx@gmail.com

How does PostgreSQL recognise "deleted" tuples by using xmax ?

#2Martijn van Oosterhout
kleptog@svana.org
In reply to: 纪晓曦 (#1)
Re: How does PostgreSQL recognise "deleted" tuples by using xmax ?

On Tue, Oct 27, 2009 at 03:55:39PM +1100, ????????? wrote:

How does PostgreSQL recognise "deleted" tuples by using xmax ?

xmax is the ID of the transaction that deleted the row. So if you are
in a transaction that sees that transaction as commited, it has been
deleted (from your point of view). If from your point of view that
transaction is aborted, it has not been deleted. If that transaction is
not finished yet, you have to wait.

Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/

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