Especially to Fred, Monty and Sasha (thanks for the answers already).
Monty,
I read the chapter and really don't see what the problem could be with the
indexes.
Fred,
EXPLAIN gives me
table type possible_keys key key_len
ref rows extra
LinkedInfo ALL NULL NULL NULL
NULL 618920
JoinedLinkedInfo ref Link_ID Link_ID 8
LinkedInfo.Link_ID 10 where used
I'm doing this from the mysql> client.
The Link_ID fields have exactly the same type. Key_buffer and others are
like I can find them in the manual.
Sasha,
I don't see how I can rewrite it without LEFT JOIN. I tried to rewrite it as
(which should be faster I think):
SELECT Sum(JoinedLinkedInfo.ValueNum) AS Amount, LinkedInfo.Record_ID FROM
JoinedLinkedInfo LEFT JOIN LinkedInfo USING (Link_ID) WHERE
JoinedLinkedInfo.Field_ID=21 GROUP BY LinkedInfo.Record_ID;
EXPLAIN fort this gives me
table type possible_keys key key_len
ref rows extra
JoinedLinkedInfo ref Field_ID Field_ID 8
??? 10
LinkedInfo eq_ref PRIMARY,Link_ID PRIMARY 8
JoinedLinkedInfo.Link_ID 1
When I try to execute this, I get the following error:
ERROR 1114: The table SQL33d2aa_0 is full.
Can anyone help?
Marc
-----Original Message-----
From: Fred Lindberg [mailto:lindberg@stripped]
Sent: vrijdag 9 april 1999 16:22
To: mysql@stripped
Subject: Re: Performance.
On Fri, 9 Apr 1999 15:59:27 +0200, Marc De Caluwé wrote:
>mySQL gives me the result (84.245 records) after... 2 hours and 59 minutes.
>
>The same query (on a similar pc) in Access takes about 6-7 minutes.
>What am I doing wrong???
Can you post table structure from MySQL (describe ...)? Are you doing
this from Access via OBDC, or from the mysql> client? Are the LINK_ID
fields of EXACTLY the same type? Is the Key_buffer big enough to hold
both indices? Other buffers?
-Sincerely, Fred
(Frederik Lindberg, Infectious Diseases, WashU, St. Louis, MO, USA)
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