[V4RB] Snail speed

[Russ Tyndall]

On 5/5/06 4:15 PM, "Ruslan Zasukhin" <sunshine at public.kherson.ua> wrote:

> On 5/5/06 11:07 PM, "Stan Busk" <maxprog at mac.com> wrote:
> 
>> Hi,
>> 
>> Just wonder why v2.3 is so slow comparing to v2.2. Queries that take
>> between 1 and 3 seconds now take between 40 and 50 seconds, this is
>> 16 times slower.
> 
> Not expect result!
> 
>> I have rebuilt indexes of course but same problem
>> appears in all my project and very simple queries.
> 
>> I am just asking  here because I am sure that can't be possible, I am likely
>> not aware  of something that has changed (again). Any clue? I heard v2.3
>> includes optimizations.
> 
> Right.
> 
> What query for example?
> 
> 
> Guys for info of all. Right now I develop new feature for Valentina:
>   EXAPLAIN of SQL query execution.
> 
> It will produce very detailed and nice for read report
> on any SQL query. Also EACH step of query will be measured by time.
> 
> This feature will give all us into hands tool to easy and fast determine
> Where some SQL query have breaks...
> 
> I am on 40-50% of done now.
> 

Ruslan, Stan:

"EXPLAIN" is going to be great.

It does seem that there is something going on inside of 2.3 that makes some
queries strangely slow. (See Mantis 0001575.)

By the way, *sometimes* I have been able to restore Valentina to normal
speed by changing some queries slightly.

For example, this line causes one of my queries to be very slow (20+ secs):

Where.... [I'm leaving out several statements]
And  State = 'NC'

But if I replace that line with

And State IN('NC')

Normal valentina speed is restored (just tenths of a second).  Such changes
don't work in all cases, but sometimes.

I'm sure Ruslan will figure out what is going on and fix this issue swiftly.

Unfortunately, I haven't been able to figure out a way to restore some
queries to normal valentina speed.

Perhaps the EXPLAIN feature will help Ruslan and Co. find and fix such
situations?

-- 
Russ Tyndall
Wake Forest, NC