Re: EXPLAIN dies with an error

[John L. Singleton]

Hi Andris,

Out of curiosity, would you mind turning on your shared SQL and let me 
know if you get a performance boost? (v 7.5 and up)

do a:
param_directput SHAREDSQL YES
db_restart
I'm curious if it's the compilation or the execution that's taking a 
long time.

Other than that, I can't say why explain died---you'll have to hold out 
for the reinforcements tomorrow!

Let me know.

Cheers,
JLS
Andris Spruds wrote:

Hi John,

Yep, I did update them. The query runned a bit (some 10%) faster afterwards,
but it's still way to slow.
Andris

----- Original Message ----- 
From: "John L. Singleton" <[EMAIL PROTECTED]>
To: "Andris Spruds" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Wednesday, April 21, 2004 12:53 AM
Subject: Re: EXPLAIN dies with an error

Hi Andris,

Did you update the optimizer statistics?

JLS

Andris Spruds wrote:

 

Dear MaxDB list,

The query
"EXPLAIN SELECT l.*, m.measurement, m.date_taken
   

FROM dbc_measurements m, dbc_lakes l
 

WHERE m.date_taken = (SELECT MAX(date_taken) FROM dbc_measurements m2 WHERE
m2.lake_id = m.lake_id AND m2.param_id=m.param_id)
AND m.param_id=41
AND m.lake_id=l.id
ORDER BY m.measurement DESC"
returns
[-9205]: System error: AK Catalog information not
found:FF000019023F022000810000000000000000000000000000000000000000000000000
   

0
 

00000000000

The problem is that the query itself takes at least 5 seconds to execute,
and I would like to optimize the tables so that it runs faster. But the
EXPLAIN statement dies with an error. Am I doing something wrong? The MaxDB
manual does not contain any useful information on the beforementioned error
message.
With best regards,
Andris Spruds






   

 

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