Thread

1. Re: TOAST performance (was Re: [GENERAL] Delete Perform

   Vadim Mikheev <vmikheev@sectorbase.com> — 2001-12-21T00:03:58Z

   > 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
   
   

2. Re: TOAST performance (was Re: [GENERAL] Delete Perform

   Bruce Momjian <pgman@candle.pha.pa.us> — 2001-12-21T03:56:06Z

   > > 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.
   
   
   -- 
     Bruce Momjian                        |  http://candle.pha.pa.us
     pgman@candle.pha.pa.us               |  (610) 853-3000
     +  If your life is a hard drive,     |  830 Blythe Avenue
     +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026