Jeff,
On 11/29/05 9:35 AM, "Jeffrey W. Baker" <[EMAIL PROTECTED]> wrote: > On Tue, 2005-11-29 at 09:45 -0500, Pollard, Mike wrote: > >> Anyway, what I did was the following. When doing a sequential scan, we >> were starting at the beginning of the table and scanning forward. If I >> threw up some threads to read ahead, then my user thread and my read >> ahead threads would thrash on trying to lock the buffer slots. So, I >> had the read ahead threads start at some distance into the table, and >> work toward the beginning. > > I believe this is commonly called a synchronous scan. I think sync scan refers to the use of a scanner shared among concurrent queries, where they can join a scan in progress from it's current location. It sounds like the logic could be shared. Sync scan (as I've described above) is another important optimization we'd like to see. - Luke ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
