Beefy Boxes and Bandwidth Generously Provided by pair Networks
Think about Loose Coupling
 
PerlMonks  

Re: (OT) perl, memory and mysql

by misterb101 (Sexton)
on Feb 10, 2006 at 18:48 UTC ( #529430=note: print w/replies, xml ) Need Help??


in reply to (OT) perl, memory and mysql

Hi,
rnahi is right. If you want to see how many rows are effected and how the joins are done execute a
explain SELECT AM.AM_A, AM.AM_M FROM AM,AR,SA,MR,SM,SR WHERE AM.AM_A ! += + SA.SA_A && AM.AM_A != AR.AR_A && AM.AM_M != MR.MR_M && AM.AM_M != SM +.SM_M;
in your command line mysql client. Any query that has table joins like 'ALL' are bad news. These are the cartesian product joins rnahi talks about.
for more information about this check for instance http://dev.mysql.com/doc/refman/4.1/en/query-speed.html
if the explain query gives you a reasonable amount of rows and joins and you still have a problem with DBI, return to the monastry!
--
Cheers,
Rob

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://529430]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others rifling through the Monastery: (5)
As of 2021-05-18 11:25 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    Perl 7 will be out ...





    Results (178 votes). Check out past polls.

    Notices?