Re: Remove xmin and cmin from frozen tuples - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Remove xmin and cmin from frozen tuples
Date
Msg-id 200509022128.j82LSf017329@candle.pha.pa.us
Whole thread Raw
In response to Re: Remove xmin and cmin from frozen tuples  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Updated TODO:
> 
> >         o Allow COPY on a newly-created table to skip WAL logging
> 
> >           On crash recovery, the table involved in the COPY would
> >           have its heap and index files truncated.  One issue is
> >           that no other backend should be able to add to the table
> >           at the same time, which is something that is currently
> >           allowed.
> 
> This is simply wrong.  (1) a table created in the current transaction
> isn't visible to anyone else, (2) the correct rollback state is for
> it not to be there, rather than be there and empty.

New text:
       o Allow COPY on a newly-created table to skip WAL logging
         On crash recovery, the table involved in the COPY would         removed or have its heap and index files
truncated. One         issue is that no other backend should be able to add to         the table at the same time,
whichis something that is         currently allowed.
 

I think we can lock a zero-length table and do this optimization.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: Remove xmin and cmin from frozen tuples
Next
From: Alvaro Herrera
Date:
Subject: Re: Remove xmin and cmin from frozen tuples