Thanks for the reply What I need to know is if there is a way to prevent the server from geting stuck after a missbehave query like the example is sent?
The problem is all other clients go so slow that no work can be done and no new connections can be made. The server is a DUAL XEON 3GH 1GB RAM, 2 SCSI HD 10.000RPM INTEL MB running SuSE Linux 9.0, my.cnf = example my.medium Andres Hocevar VENEZUELA > [EMAIL PROTECTED] wrote: >> Hi >> >> I need to prevent users from holding down the server,issuing the next >> query the server becomes so slow that the other clients can't even >> login!, the tables are around 6Million records: >> >> SELECT (some fields ), sum(more fields) AS calcfield >> FROM table1 INNER JOIN table2 ON ... INNER JOIN table3 ON .... GROUP >> BY (group field) >> HAVING table1.field = 'something' AND calcfield BETWEEEN 1 AND 10 >> >> if the same query is changed to >> >> SELECT (some fields ), sum(more fields) AS calcfield >> FROM table1 INNER JOIN table2 ON ... INNER JOIN table3 ON .... WHERE >> table1.field = 'something' >> GROUP BY (group field) >> HAVING calcfield BETWEEEN 1 AND 10 >> >> the query takes 3sec! >> >> Is there a way to handle this situations in witch one thread takes >> over the whole server?? > > HAVING clause is applied before data are sent to the client without any > optimization. That is why you first query is slower than second one. > > Turn on slow query log to find queries that take a long time to execute: > http://www.mysql.com/doc/en/Slow_query_log.html > > > > -- > For technical support contracts, goto > https://order.mysql.com/?ref=ensita This email is sponsored by > Ensita.net http://www.ensita.net/ > __ ___ ___ ____ __ > / |/ /_ __/ __/ __ \/ / Egor Egorov > / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] > /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net > <___/ www.mysql.com > > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
