tag:blogger.com,1999:blog-15440695.post6654449729965596193..comments2024-02-29T10:39:57.857-05:00Comments on Alex Fatkulin's Blog: Hot backup mode and a little known factAlex Fatkulinhttp://www.blogger.com/profile/06361288475877100451noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-15440695.post-55999941947235913132009-10-30T16:27:42.305-04:002009-10-30T16:27:42.305-04:00hello, thanks for the help, the truth to my schedu...hello, thanks for the help, the truth to my schedule I have trouble in databases, told me that there is programming style called extreme programing, I believe that each person develops his style, but I wonder if this exists? thanks ..Fitnesshttp://www.fitnesstonic.com/noreply@blogger.comtag:blogger.com,1999:blog-15440695.post-7713905477978170732009-01-27T11:37:00.000-05:002009-01-27T11:37:00.000-05:00Jonathan,thanks for the correction... you're right...Jonathan,<BR/><BR/>thanks for the correction... you're right.<BR/><BR/>What you say can be confirmed by ding an "alter system checkpoint" (and making sure blocks are no longer dirty using v$bh/x$bh) as well.<BR/><BR/>I'll make an update to the post and reference your comment, thanks again.Alex Fatkulinhttps://www.blogger.com/profile/06361288475877100451noreply@blogger.comtag:blogger.com,1999:blog-15440695.post-11479036069570999162009-01-27T11:06:00.000-05:002009-01-27T11:06:00.000-05:00Alex,It's not the write to disk that matters, it's...Alex,<BR/><BR/>It's not the write to disk that matters, it's the read from disk to buffer.<BR/><BR/>The full block is copied into the redo buffer on the first change after the block has been read from disk. (If you update just one row, you'll see you get two change records - the first is the block, the second is the normal redo record for the update).<BR/><BR/>If you check x$bh.flag you can see that bit 25 (redo_since_read) gets set on this first change, and the flag can't persist if the block gets flushed from memory.<BR/><BR/>Regards<BR/>Jonathan LewisAnonymousnoreply@blogger.com