Re: Help! Very bad SQL bug in 7.2.3.0.0

Tom,

How are you joining these tables? Try adding the last line (shown below). I've speeded up many a query by relating the last table back to the first. Note that this is not possible in every instance, but if so, give it a try.

where	a.x = b.x and
	b.x = c.x and
	c.x = d.x and
	d.x = e.x and
	e.x = a.x	-- add this and see what happens

good.luck = true

-- 
 Les Gainous, lesgainous_at_earthlink.net

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Tom Fielden wrote:


> 

> Recipe for bad results:


> 

> Join several tables sequentially like so: a-b-c-d-e

>    Put a simple on 'e'.

>    Observe that the query runs fast.

>    Now put a simple condition on 'a'

>    observe that the query is 100 times slower! Sheesh!

> 

> This is so incredibly bad that Microsoft SQL server looks like a

> viable alternative.

> 

> Please don't let me get sucked into the 'Gates' of hell! What is

> the work-around?

> 

> Also, this seems like an extremely common type of query to run. In

> fact, a developer down the hall has an almost identical problem with

> the same effect.

> 

> If you have any ideas, I would greatly appreciate hearing from you.

> 

> Thanks in advance,

> 

> Tom Fielden

> Mentor Graphics Corp.