Question Memcache or APC

[semprot]

1. I have memcache and APC installed. Which one should i use for vb optimise?
2. Should i set this setting on? >> "vB Optimise: Overload vBCache Handler". What's the pros & cons?

Thanks.

 

[Fillip H.]

1. I'd go with APC, since memcache is only used if you have multiple servers.

2. Pros being more stuff gets cached, cons I don't know.

 

[semprot]

Thanks for the quick response.. I am trying apc now (i used memcache on vb optimise lite)

 

[semprot]

Ok ive tried APC for some minutes (maybe up to 1h), but i got this error later "Warning: Unknown: Unable to allocate memory for pool. in Unknown on line 0".
When i switched to memcache, i dont get that error.
But personally, i feel APC is much faster.
What should i do to fix that APC error?

 

[Fillip H.]

The first and second results for that error message on Google has potential answers, see the answers from the php.net guys here: https://bugs.php.net/bug.php?id=58982

 

[semprot]

The first and second results for that error message on Google has potential answers, see the answers from the php.net guys here: https://bugs.php.net/bug.php?id=58982

Thanks. it seems i have to tweak my apc setting according to that link..

 

[semprot]

I use APC now, and on system test, i got this message "Your Opcache Operator extension is functioning, however it is unable to store data. Please check your extension configuration.".
What APC configuration should i check?

Thanks.

 

[Fillip H.]

Ensure that the variable storage is large enough and that the cacher is enabled

 

[semprot]

Thanks it seems because my APC has very high defragmentation although i've set its ttl to zero. Defragmentation can increased until 100%.
After i flushed the cache, all system tests are passed.

 

[semprot]

My next question is not directly related to vb optimise, can i ask about apc here?
how to avoid high defragmentation? here is my apc setting

apc.cache_by_default	1
apc.canonicalize	1
apc.coredump_unmap	0
apc.enable_cli	1
apc.enabled	1
apc.file_md5	0
apc.file_update_protection	2
apc.filters	
apc.gc_ttl	3600
apc.include_once_override	0
apc.lazy_classes	0
apc.lazy_functions	0
apc.max_file_size	20M
apc.mmap_file_mask	
apc.num_files_hint	1000
apc.preload_path	
apc.report_autofilter	0
apc.rfc1867	0
apc.rfc1867_freq	0
apc.rfc1867_name	APC_UPLOAD_PROGRESS
apc.rfc1867_prefix	upload_
apc.rfc1867_ttl	3600
apc.serializer	default
apc.shm_segments	1
apc.shm_size	256M
apc.slam_defense	1
apc.stat	0
apc.stat_ctime	0
apc.ttl	0
apc.use_request_time	1
apc.user_entries_hint	4096
apc.user_ttl	7200
apc.write_lock	1

And vb optimise just saved me 4 mill queries on my first day

 

[Fillip H.]

That is sadly beyond my area of expertise

 

[semprot]

Ensure that the variable storage is large enough and that the cacher is enabled

I just rebuilt my litespeed and i got "Your Opcache Operator extension is functioning, however it is unable to store data. Please check your extension configuration." again.
APC setting seems the same compared with before the rebuild.

I've tried to run a PHP script :

<?php
$bar = 'BAR';
apc_store('foo', $bar);
var_dump(apc_fetch('foo'));
?>

And it works perfectly (it returns this response) :

string(3) "BAR"

Apc fragmentation is low (near 0.x%).

And on forum home page i notice that the number on "Reduced on this page: MySQL XX,00%" is lower than before rebuilt.
Now is about 15-25.
Before, it was about 44-60.

So it seems less things are cached now.

 

[Fillip H.]

The apc_store and apc_get would need to be called in two separate scripts to give an accurate test.

<?php 
$bar = 'BAR'; 
apc_store('foo', $bar); 
?>

<?php
var_dump(apc_fetch('foo'));
?>

Does it still produce the correct content?

 

[semprot]

The apc_store and apc_get would need to be called in two separate scripts to give an accurate test.

<?php 
$bar = 'BAR'; 
apc_store('foo', $bar); 
?>

<?php
var_dump(apc_fetch('foo'));
?>

Does it still produce the correct content?

I tried to separate to 2 files, and apc_fetch sometimes failed, sometimes it is fine if i refresh it several times..

Sometimes it returns :

bool(false)

Sometimes (very rarely) it returns :

string(3) "BAR"

So what setting should i check?

 

[Fillip H.]

That'd be the issue then, it should return bar 100% of the time.

Try putting this script on your server and observing it:
APC INFO <?php echo $host ?> (save as apc.php and upload it somewhere in your public_html dir)

Screenshot the View Host Stats tab and I might be able to advise

 

[eva2000]

semprot take a read of High APC Fragmentation - LiteSpeed Support Forums if that is same semprot on litespeed forums

 

[semprot]

semprot take a read of High APC Fragmentation - LiteSpeed Support Forums if that is same semprot on litespeed forums

That's me.. Thanks.

I think i've figured out the problem. I use litespeed + suphp >> i shouldn't use APC / xcache because they won't work well.
I will try to use eAccelerator now.

I think that should be written into a thread here and stickied :
"If you use litespeed + suphp, do not use APC / xcache"

I'm sure it will help more users here