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be careful with size of keys being used in joins

P: n/a
Hi, I want to share my experience with you. If you have large tables,
and you are doing joins, be extra careful that the keys in the joins
have exactly the same size (and type). Donít mix mediumint and int
for example.

There is a huge performance hit if your join keys are not the same
size. This IS documented on mysql.com, but not everyone reads
everything :D

Just beware!

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Sep 12 '05 #1
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P: n/a
"steve" <Us************@dbForumz.com> wrote in message
news:4_***************************************@dbf orumz.com...
Hi, I want to share my experience with you. If you have large tables,
and you are doing joins, be extra careful that the keys in the joins
have exactly the same size (and type). Don't mix mediumint and int
for example.

There is a huge performance hit if your join keys are not the same
size. This IS documented on mysql.com, but not everyone reads
everything :D

Just beware!


Owwwhhh! So that's it.
It is documented and I didn't read it.

Thank you Steve
Thomas Bartkus
Sep 13 '05 #2

P: n/a
"" wrote:
"steve" <Us************@dbForumz.com> wrote in message
news:4_***************************************@dbf orumz.com...
Hi, I want to share my experience with you. If you have

large tables,
and you are doing joins, be extra careful that the keys in

the joins
have exactly the same size (and type). Don't mix mediumint

and int
for example.

There is a huge performance hit if your join keys are not

the same
size. This IS documented on mysql.com, but not everyone reads
everything :D

Just beware!


Owwwhhh! So that's it.
It is documented and I didn't read it.

Thank you Steve
Thomas Bartkus


I have spent AT LEAST A DAY dealing with all kind of weird mysql
errors (error .., mysql has gone away), which were solved by making
sure the join fields are the same. The problem is that there is no
way to tie the error to the this problem.

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Articles individually checked for conformance to usenet standards
Topic URL: http://www.dbforumz.com/mySQL-carefu...ict255010.html
Visit Topic URL to contact author (reg. req'd). Report abuse: http://www.dbforumz.com/eform.php?p=881602
Sep 13 '05 #3

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