Обсуждение: Re: TOAST performance (was Re: [GENERAL] Delete Perform

> If "pre-page WAL write" means the value of the page before the current
> changes, then there is generally another reason for writing it out.

Bruce, "*pre*-page" is confusing - we write "after-change" page
image to WAL.

> When the system comes back up, we need to do a rollback on
> transaction B since it did not commit and we need the "pre-page"
> to know how to undo the change for B that got saved in step 6 above.

Brian, PGSQL still uses non-overwriting storage manager -
removing rows inserted by aborted transactions is not required.

Vadim

> > If "pre-page WAL write" means the value of the page before the current
> > changes, then there is generally another reason for writing it out.
> 
> Bruce, "*pre*-page" is confusing - we write "after-change" page
> image to WAL.

Yes, I didn't like pre-page either.  Changed.


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