On Monday 24 July 2006 09:06, Duncan Hill wrote:
On Monday 24 July 2006 09:05, Ratheesh K J wrote:
Hello All,
I run a select query to see its speed. It took around 5 seconds. Now i
run the same query simultaneously twice usng two instances of the client
tool. It took 10 seconds for both the queris to complete. Its not 5 secs
+ 5 secs. Both the queries were running till 10 secs when i saw using
In the case of a single disk serving up the data, two simultaneous queries
for the same data will cause the disk to go back and forth trying to
satisfy each query. Even with a mirrored pair of disks, you're going to
have problems unless you have a very intelligent disk controller that can
split the requests across the two disks.
Forgot to add - do the queries require table locks? If so, the first one is
going to lock the table, run in 5 seconds, unlock. Then the second one, and
then the third. Assuming no query cache.
4 messages in com.mysql.lists.mysqlRe: Select Query taking time
