Hello Monty, Thank you for your note and feedback.
After getting excellent assistance, I'm using JDBC setMaxRows rather than LIMIT, which gives me portability. I'll investigate SQL_CALC_FOUND_ROW option further. I notice I would need to first upgrade to MySQL 4.x, though and then find / work out how to use it with JDBC. It would be great to do only one query, which means the processing would be reduced from approx. 25 to 4 seconds. I'd say, that is a great reduction. Kind regards Emmanuel > -----Original Message----- > From: Michael Widenius [mailto:[EMAIL PROTECTED]] > Sent: 21 January 2002 00:44 > To: Emmanuel van der Meulen > Cc: MySQL General List; MySQL Java List > Subject: RE: Understanding throughput with JDBC > > > > Hi! > > >>>>> "Emmanuel" == Emmanuel van der Meulen <[EMAIL PROTECTED]> writes: > > Emmanuel> Hello Mark, > Emmanuel> Thank you for the note and feedback. BTW, it was not > over a network. Both > Emmanuel> on local PC. So all the time went into building the > resultset in memory. > Emmanuel> I'm surprised at the time that takes. > > Emmanuel> Further to why I'm desirous to do this query, twofold. > One I get the record > Emmanuel> count (rows in the table); since realised there are > other ways to get he > Emmanuel> number of rows. For the second requirement I cannot > see an alternative. > Emmanuel> Not on this table, but on another where I keep a > timestamp, I'd like to get > Emmanuel> the 50 most recent inserts. So what I do is; (SELECT * FROM > Emmanuel> MEMBERSHIPSTRACKING ORDER BY ACTIVITYTIMESTAMP DESC) > thus get all the rows, > Emmanuel> ordered desc on timestamp and then I have the most > recent 50 inserts. If > Emmanuel> anyone could assist me with this, I'd use other means, > rather than > Emmanuel> retrieving the full resultset. > > Why can't you use 'LIMIT 50' to get the latest 50 rows ? > (As Mark asked, why do you have to use LIMIT 10000) > > You can also use SQL_CALC_FOUND_ROW option to avoid to do two queries, > if you want to know how many rows the WHERE statement actually matched > (see the MySQL manual for more information about this topic). > > Regards, > Monty > > -- > For technical support contracts, goto https://order.mysql.com/ > __ ___ ___ ____ __ > / |/ /_ __/ __/ __ \/ / Mr. Michael Widenius <[EMAIL PROTECTED]> > / /|_/ / // /\ \/ /_/ / /__ MySQL AB, CTO > /_/ /_/\_, /___/\___\_\___/ Helsinki, Finland > <___/ www.mysql.com --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
