Re: Performance tips

2008-12-30 Thread Baron Schwartz
Hi Jim, On Tue, Dec 30, 2008 at 5:54 PM, Jim Lyons wrote: > On Sat, Dec 27, 2008 at 12:38 PM, Jake Maul wrote: > >> >> 3) Obviously it'd probably be faster if you weren't using >> SQL_NO_CACHE... guessing you just did that to show us what it's like >> that way? >> >> > Why would SQL_NO_CACHE slo

Re: Performance tips

2008-12-30 Thread Jim Lyons
On Sat, Dec 27, 2008 at 12:38 PM, Jake Maul wrote: > > 3) Obviously it'd probably be faster if you weren't using > SQL_NO_CACHE... guessing you just did that to show us what it's like > that way? > > Why would SQL_NO_CACHE slow it down? By not checking the cache or storing the resultset into cac

Re: Performance tips

2008-12-27 Thread ewen fortune
Mmm I just tested this and it does indeed work (although i tested with slightly less rows :o) ) explain select count(*) , date_format(calldate, '%y-%m-%d') as m from cdr_warehouse group by m \G *** 1. row *** id: 1 select_type: SIMPLE

Re: Performance tips

2008-12-27 Thread ewen fortune
Hi, On Sat, Dec 27, 2008 at 6:15 PM, Chris Picton wrote: > Hi > > I am trying to get to grips with understanding mysql performance. > > I have the following query: > > select sql_no_cache count(*), date_format(calldate, '%y-%m-%d') as m from > cdr_warehouse group by m; > > This gives me: > 115 ro

Re: Performance tips

2008-12-27 Thread Dan Nelson
In the last episode (Dec 27), Chris Picton said: > I am trying to get to grips with understanding mysql performance. > > I have the following query: > > select sql_no_cache count(*), date_format(calldate, '%y-%m-%d') as m from > cdr_warehouse group by m; > > This gives me: > 115 rows in set (59

Re: Performance tips

2008-12-27 Thread Jake Maul
usly it'd probably be faster if you weren't using SQL_NO_CACHE... guessing you just did that to show us what it's like that way? 4) I'd check the values of sort_buffer_size and read_rnd_buffer_size. Perhaps you could benefit from raising them slightly. As for general performance

Performance tips

2008-12-27 Thread Chris Picton
Hi I am trying to get to grips with understanding mysql performance. I have the following query: select sql_no_cache count(*), date_format(calldate, '%y-%m-%d') as m from cdr_warehouse group by m; This gives me: 115 rows in set (59.52 sec) mysql> explain select count(*), date_format(callda