Re: ice-broker scan thread

Jeff,

On 11/29/05 9:35 AM, "Jeffrey W. Baker" <jwbaker(at)acm(dot)org> 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