Multiple simultaneous requests and cache generation

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Piotrek Karaś	Wednesday 17 December 2008 11:18:29 am Hi all, Can anyone tell me, or at least give me a hint where to look for the answer: Whenever <b>cache-block</b> or <b>view-cache</b> are expired or physically cleared, what's eZ approach in generating new ones: will all the simultaneous requests compete in generating cache-blocks or view-cache, or will the first one set some sort of lock, making all other requests wait for it being generated? Or maybe any other approach? This seems to be performance-wise <b>important for heavy-traffic sites</b>, as many competing requests could kill a server in case of accidental cache clear, for example. Any comments or clarification on this subject greatly appreciated! Cheers, Piotrek <i>PS. This is a question forwarded from a potential heavy-traffic eZ client, so it would be great if I could get back to them with some feedback... ;)</i> -- Company: mediaSELF Sp. z o.o., http://www.mediaself.pl eZ references: http://ez.no/partners/worldwide_partners/mediaself eZ certified developer: http://ez.no/certification/verify/272585 eZ blog: http://ez.ryba.eu
André R.	Monday 29 December 2008 4:04:07 am A lock is used on view cache, but this is subject to change at least in the cluster code: http://issues.ez.no/IssueView.php?Id=14204&activeItem=16 eZ Online Editor 5: http://projects.ez.no/ezoe \|\| eZJSCore (Ajax): http://projects.ez.no/ezjscore \|\| eZ Publish EE http://ez.no/eZPublish/eZ-Publish-Enterprise-Subscription @: http://twitter.com/andrerom

Author

Message

Piotrek Karaś

Wednesday 17 December 2008 11:18:29 am

Hi all,

Can anyone tell me, or at least give me a hint where to look for the answer:

Whenever cache-block or view-cache are expired or physically cleared, what's eZ approach in generating new ones: will all the simultaneous requests compete in generating cache-blocks or view-cache, or will the first one set some sort of lock, making all other requests wait for it being generated? Or maybe any other approach?

This seems to be performance-wise important for heavy-traffic sites, as many competing requests could kill a server in case of accidental cache clear, for example.

Any comments or clarification on this subject greatly appreciated!

Cheers,
Piotrek

PS. This is a question forwarded from a potential heavy-traffic eZ client, so it would be great if I could get back to them with some feedback... ;)

--
Company: mediaSELF Sp. z o.o., http://www.mediaself.pl
eZ references: http://ez.no/partners/worldwide_partners/mediaself
eZ certified developer: http://ez.no/certification/verify/272585
eZ blog: http://ez.ryba.eu

André R.

Monday 29 December 2008 4:04:07 am

A lock is used on view cache, but this is subject to change at least in the cluster code:
http://issues.ez.no/IssueView.php?Id=14204&activeItem=16

eZ Online Editor 5: http://projects.ez.no/ezoe || eZJSCore (Ajax): http://projects.ez.no/ezjscore || eZ Publish EE http://ez.no/eZPublish/eZ-Publish-Enterprise-Subscription
@: http://twitter.com/andrerom

eZ debug

Timing:	Jan 20 2025 08:00:54
Script start
Timing:	Jan 20 2025 08:00:54
Module start 'layout'
Timing:	Jan 20 2025 08:00:54
Module start 'content'
Timing:	Jan 20 2025 08:00:56
Module end 'content'
Timing:	Jan 20 2025 08:00:56
Script end

Main resources:

Total runtime	1.1361 sec
Peak memory usage	4,096.0000 KB
Database Queries	54

Timing points:

Checkpoint	Start (sec)	Duration (sec)	Memory at start (KB)	Memory used (KB)
Script start	0.0000	0.0058	589.3047	152.6406
Module start 'layout'	0.0058	0.0038	741.9453	39.4766
Module start 'content'	0.0096	1.1250	781.4219	534.6250
Module end 'content'	1.1346	0.0015	1,316.0469	12.1250
Script end	1.1361		1,328.1719

Time accumulators:

Accumulator	Duration (sec)	Duration (%)	Count	Average (sec)
Ini load
Load cache	0.0031	0.2761	16	0.0002
Check MTime	0.0013	0.1149	16	0.0001
Mysql Total
Database connection	0.0007	0.0637	1	0.0007
Mysqli_queries	1.0860	95.5853	54	0.0201
Looping result	0.0005	0.0475	52	0.0000
Template Total	1.1004	96.9	2	0.5502
Template load	0.0024	0.2087	2	0.0012
Template processing	1.0980	96.6466	2	0.5490
Template load and register function	0.0001	0.0096	1	0.0001
states
state_id_array	0.0019	0.1642	1	0.0019
state_identifier_array	0.0008	0.0727	2	0.0004
Override
Cache load	0.0019	0.1715	16	0.0001
Sytem overhead
Fetch class attribute can translate value	0.0012	0.1021	2	0.0006
Fetch class attribute name	0.0011	0.0976	4	0.0003
XML
Image XML parsing	0.0012	0.1064	2	0.0006
class_abstraction
Instantiating content class attribute	0.0000	0.0007	4	0.0000
General
dbfile	0.0022	0.1934	24	0.0001
String conversion	0.0000	0.0007	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
2	content/datatype/view/ezimage.tpl	<No override>	extension/sevenx/design/simple/templates/content/datatype/view/ezimage.tpl
2	content/datatype/view/ezxmltext.tpl	<No override>	extension/community_design/design/suncana/templates/content/datatype/view/ezxmltext.tpl
3	content/datatype/view/ezxmltags/paragraph.tpl	<No override>	extension/ezwebin/design/ezwebin/templates/content/datatype/view/ezxmltags/paragraph.tpl
2	content/datatype/view/ezxmltags/line.tpl	<No override>	design/standard/templates/content/datatype/view/ezxmltags/line.tpl
1	print_pagelayout.tpl	<No override>	extension/community/design/community/templates/print_pagelayout.tpl
Number of times templates used: 11 Number of unique templates used: 6

Time used to render debug report: 0.0001 secs