Very high CPU utilisation with 40-50 concurrent connection on Innodb table

[Pankaj joshi]

I am getting very high cpu utilisation around 90% when 40-50 concurrent connections are executing .

The version of mysql is 5.1.32 community log

RAM 8GB


processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 2.80GHz
stepping : 1
cpu MHz : 2800.100
cache size : 1024 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall lm constant_tsc pni monitor ds_cpl cid cx16 xtpr
bogomips : 7004.24
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 2.80GHz
stepping : 1
cpu MHz : 2800.100
cache size : 1024 KB
physical id : 1
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall lm constant_tsc pni monitor ds_cpl cid cx16 xtpr
bogomips : 7004.24
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 2
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 2.80GHz
stepping : 1
cpu MHz : 2800.100
cache size : 1024 KB
physical id : 2
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall lm constant_tsc pni monitor ds_cpl cid cx16 xtpr
bogomips : 7004.24
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 3
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 2.80GHz
stepping : 1
cpu MHz : 2800.100
cache size : 1024 KB
physical id : 3
siblings : 1
core id : 0
cpu cores : 1
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall lm constant_tsc pni monitor ds_cpl cid cx16 xtpr
bogomips : 7004.24
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

show processlist

Id db Command Time State Info
1 \N Binlog Dump 13894 Has sent all binlog to slave; waiting for binlog to be updated \N
106164 DRS Sleep 3956 \N
3588858 \N Query 0 \N show full processlist
4297685 heywire Query 0 Sending data select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event ORDER by id LIMIT 10200,300
4297688 heywire Query 0 Sending data select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event where featured='true' ORDER by id LIMIT 3000,300
4297721 heywire Query 0 freeing items select id, username, password, main_image, back_image, creation_date from person where username='_vanya'
4297760 heywire Sleep 0 \N
4297762 heywire Query 0 Sending data select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event where featured='true' ORDER by id LIMIT 6900,300
4297763 \N Connect \N Reading from net \N
4297770 heywire Query 0 Sending data select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event ORDER by id LIMIT 10500,300
4297772 \N Sleep 0 \N
4297774 \N Connect \N Reading from net \N
4297777 heywire Sleep 0 \N
4297779 heywire Query 0 Sending data select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event where featured='true' ORDER by id LIMIT 9900,300
4297775 \N Sleep 0 \N
4297781 \N Sleep 0 \N
4297783 \N Connect \N Reading from net \N
4297784 heywire Sleep 0 \N
4297790 \N Connect \N Reading from net \N
4297789 \N Connect \N Reading from net \N
4297788 heywire Sleep 0 \N
4297787 heywire Sleep 0 \N
4297786 \N Connect \N Reading from net \N
4297785 \N Connect \N Reading from net \N
4297782 \N Connect \N Reading from net \N

the table event has only 10000 records

the table strucutre for event table is


CREATE TABLE `event` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`user_id` int(11) DEFAULT NULL,
`start_date` timestamp NULL DEFAULT NULL,
`end_date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`main_image` varchar(2000) DEFAULT NULL,
`back_image` varchar(2000) DEFAULT NULL,
`description` varchar(2000) DEFAULT NULL,
`pretty_url` varchar(2000) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`url` varchar(2000) DEFAULT NULL,
`username` varchar(2000) DEFAULT NULL,
`location` varchar(255) DEFAULT NULL,
`creation_date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`category` varchar(255) DEFAULT NULL,
`featured` varchar(10) DEFAULT NULL,
`last_post_count` int(11) DEFAULT NULL,
`address` varchar(500) DEFAULT NULL,
`address2` varchar(500) DEFAULT NULL,
`city` varchar(255) DEFAULT NULL,
`state` varchar(255) DEFAULT NULL,
`zip` varchar(100) DEFAULT NULL,
`country` varchar(100) DEFAULT NULL,
`locked` varchar(10) DEFAULT NULL,
`tinkurl` varchar(200) DEFAULT NULL,
`last_post` varchar(255) DEFAULT NULL,
`ad_image` varchar(2000) DEFAULT NULL,
`ad_url` varchar(2000) DEFAULT NULL,
`moderated` varchar(10) DEFAULT NULL,
`flag` int(11) DEFAULT NULL,
`projected_page` varchar(10) DEFAULT NULL,
`projected_main_image` varchar(2000) DEFAULT NULL,
`projected_back_image` varchar(2000) DEFAULT NULL,
`projected_page_twitter` varchar(255) DEFAULT NULL,
`code_plugin` varchar(2000) DEFAULT NULL,
`last_pub_date` bigint(20) unsigned DEFAULT NULL,
`comments` text,
PRIMARY KEY (`id`),
KEY `user_id` (`user_id`),
KEY `pretty_url` (`pretty_url`(767)),
KEY `idx_event_description` (`category`)
) ENGINE=InnoDB


the query which is running very frequently is
select id, name, description, main_image, back_image, start_date, end_date, user_id, username, location, category, email, url, pretty_url, tinkurl, creation_date, last_post from event ORDER by id LIMIT 10500,300

Please let me know if anything else would be required .

Thanks