Problems with sudden high load

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Author	Message
Helle Andersen	Wednesday 10 January 2007 3:07:04 am We have for the past weeks experienced extremely hight peaks in our CPU usage which we cannot explain. From a normal 2-8 % CPU usage on the database the CPU usage suddenly increases to 50-90% - without more users than ordinarily. e.g. Date user idle hits (otoba) 09:00:01 AM 2.04 96.99 2685 09:10:01 AM 3.68 95.45 2981 09:20:01 AM 6.23 92.51 3771 09:30:01 AM 30.75 65.51 4518 09:40:01 AM 82.15 10.57 4573 09:50:01 AM 3.71 94.12 4696 10:00:01 AM 4.70 94.08 5801 10:10:01 AM 5.41 93.43 3992 Restarting MySQL (and sometimes also clearing the entire cache) usually solves the problem. We run a cluster solution with a powerfull database, 4 front end webservers and two load balancers. As far as we can se the this CPU usage is not caused by more user traffic, but we cannot see what causes this extremely high load. Anyone else experience similar problems or any ideas ? Whether or not this is related to another problem we have I do not know: see http://ez.no/community/forum/developer/database_inconsistency_replacement_of_attributes Helle Andersen

Author

Message

Wednesday 10 January 2007 3:07:04 am

We have for the past weeks experienced extremely hight peaks in our CPU usage which we cannot explain. From a normal 2-8 % CPU usage on the database the CPU usage suddenly increases to 50-90% - without more users than ordinarily.
e.g.

Date                  user          idle         hits (otoba)

09:00:01 AM       2.04            96.99	         2685
09:10:01 AM       3.68            95.45	         2981
09:20:01 AM       6.23            92.51	         3771
09:30:01 AM       30.75          65.51	        4518
09:40:01 AM       82.15          10.57	        4573
09:50:01 AM       3.71            94.12	         4696
10:00:01 AM       4.70            94.08	          5801
10:10:01 AM       5.41            93.43	          3992

Restarting MySQL (and sometimes also clearing the entire cache) usually solves the problem.
We run a cluster solution with a powerfull database, 4 front end webservers and two load balancers.
As far as we can se the this CPU usage is not caused by more user traffic, but we cannot see what causes this extremely high load. Anyone else experience similar problems or any ideas ?
Whether or not this is related to another problem we have I do not know: see http://ez.no/community/forum/developer/database_inconsistency_replacement_of_attributes
Helle Andersen

eZ debug

Timing:	Jan 19 2025 01:07:55
Script start
Timing:	Jan 19 2025 01:07:55
Module start 'layout'
Timing:	Jan 19 2025 01:07:55
Module start 'content'
Timing:	Jan 19 2025 01:07:56
Module end 'content'
Timing:	Jan 19 2025 01:07:56
Script end

Main resources:

Total runtime	0.7110 sec
Peak memory usage	4,096.0000 KB
Database Queries	46

Timing points:

Checkpoint	Start (sec)	Duration (sec)	Memory at start (KB)	Memory used (KB)
Script start	0.0000	0.0079	589.1563	152.6250
Module start 'layout'	0.0079	0.0030	741.7813	39.4453
Module start 'content'	0.0109	0.6988	781.2266	403.8750
Module end 'content'	0.7097	0.0013	1,185.1016	8.1641
Script end	0.7110		1,193.2656

Time accumulators:

Accumulator	Duration (sec)	Duration (%)	Count	Average (sec)
Ini load
Load cache	0.0035	0.4863	16	0.0002
Check MTime	0.0014	0.1905	16	0.0001
Mysql Total
Database connection	0.0014	0.2000	1	0.0014
Mysqli_queries	0.6729	94.6384	46	0.0146
Looping result	0.0004	0.0573	44	0.0000
Template Total	0.6758	95.0	2	0.3379
Template load	0.0023	0.3207	2	0.0011
Template processing	0.6735	94.7223	2	0.3367
Template load and register function	0.0002	0.0226	1	0.0002
states
state_id_array	0.0014	0.2031	1	0.0014
state_identifier_array	0.0011	0.1576	2	0.0006
Override
Cache load	0.0018	0.2509	11	0.0002
Sytem overhead
Fetch class attribute can translate value	0.0005	0.0761	1	0.0005
Fetch class attribute name	0.0005	0.0721	1	0.0005
XML
Image XML parsing	0.0001	0.0169	1	0.0001
class_abstraction
Instantiating content class attribute	0.0000	0.0006	1	0.0000
General
dbfile	0.0007	0.0924	10	0.0001
String conversion	0.0000	0.0013	4	0.0000
Note: percentages do not add up to 100% because some accumulators overlap

Templates used to render the page:

Usage	Requested template	Template	Template loaded
1	node/view/full.tpl	full/forum_topic.tpl	extension/sevenx/design/simple/override/templates/full/forum_topic.tpl
1	content/datatype/view/ezxmltext.tpl	<No override>	extension/community_design/design/suncana/templates/content/datatype/view/ezxmltext.tpl
2	content/datatype/view/ezxmltags/line.tpl	<No override>	design/standard/templates/content/datatype/view/ezxmltags/line.tpl
2	content/datatype/view/ezxmltags/paragraph.tpl	<No override>	extension/ezwebin/design/ezwebin/templates/content/datatype/view/ezxmltags/paragraph.tpl
1	content/datatype/view/ezxmltags/literal.tpl	<No override>	extension/community/design/standard/templates/content/datatype/view/ezxmltags/literal.tpl
1	print_pagelayout.tpl	<No override>	extension/community/design/community/templates/print_pagelayout.tpl
Number of times templates used: 8 Number of unique templates used: 6

Time used to render debug report: 0.0001 secs