RE: In-placre persistance change of a relation

Hello, Tsunakawa-San


> Do you know the reason why data copy was done before?  And, it may be
> odd for me to ask this, but I think I saw someone referred to the past
> discussion that eliminating data copy is difficult due to some processing at
> commit.  I can't find it.
I can share 2 sources why to eliminate the data copy is difficult in hackers thread.

Tom's remark and the context to copy relation's data.
https://www.postgresql.org/message-id/flat/31724.1394163360%40sss.pgh.pa.us#31724.1394163360@sss.pgh.pa.us

Amit-San quoted this thread and mentioned that point in another thread.
https://www.postgresql.org/message-id/CAA4eK1%2BHDqS%2B1fhs5Jf9o4ZujQT%3DXBZ6sU0kOuEh2hqQAC%2Bt%3Dw%40mail.gmail.com

Best,
    Takamichi Osumi