Random add/set errors on Debian/Memcached 1.1.12

[dormando]

Are there any PHP folks on the list who want to step up participation a 
bit? I loathe the language but understand it's popular; we get a lot of 
questions and need more docs, people helping out, etc.

I'm willing to bet your pecl/memcache client could use an upgrade; I've 
seen a lot of reports of this issue happening with the older client.

Also, 1.1.12 is fairly old and has _some_ bugs... I wouldn't be quick to 
blame it on your issue though.

Otherwise, you should strace a process that's exhibiting issues and see 
what the actual traffic between memcached and your client process looks 
like. You can pull the real errors from that, send to the list, and 
we'll work from there.

-Dormando

Mauro Maggi wrote:
> We got some random errors with Memcached 1.1.12 on a (32-bit) production
> server running Debian 4.0r1. The client API is the one provided with php
> 4.4.4
> 
> memcache_set() and memcache_add() randomly fail when trying to set large
> values ( > 30kb); the larger the entry length, the larger the number of
> failures. Moreover, we get random notices like this one: 
> "Notice: memcache_get_stats() [function.memcache-get-stats]: Server
> 192.168.0.13 (tcp 11211) failed with: Failed reading line from stream
> (0) in /path/to/script.php"
> 
> The same setup on a local developing box, with the same setup, gives us
> no failures and everything works ok.
> 
> What's wrong in our production box? Is there a way to get an insight on
> why the functions are failing, other than their "false" return value?
> 
> What follows is the phpinfo() memcached reported configuration and the output of the memcache_get_advanced_server_stats on our production box:
> 
> Revision 	$Revision: 1.92 $
> memcache.allow_failover	1
> memcache.chunk_size	8192
> memcache.default_port	11211
> memcache.hash_function	crc32
> memcache.hash_strategy	standard
> memcache.max_failover_attempts	20
> 
> ----
> 
> Server stats:array(19) {
>   ["pid"]=>
>   string(4) "2735"
>   ["uptime"]=>
>   string(6) "355498"
>   ["time"]=>
>   string(10) "1196778820"
>   ["version"]=>
>   string(6) "1.1.12"
>   ["rusage_user"]=>
>   string(10) "230.270391"
>   ["rusage_system"]=>
>   string(10) "452.140257"
>   ["curr_items"]=>
>   string(7) "1012241"
>   ["total_items"]=>
>   string(8) "10852467"
>   ["bytes"]=>
>   string(10) "1429072369"
>   ["curr_connections"]=>
>   string(3) "469"
>   ["total_connections"]=>
>   string(7) "6798948"
>   ["connection_structures"]=>
>   string(3) "654"
>   ["cmd_get"]=>
>   string(8) "10898327"
>   ["cmd_set"]=>
>   string(8) "10852467"
>   ["get_hits"]=>
>   string(7) "8061893"
>   ["get_misses"]=>
>   string(7) "2836434"
>   ["bytes_read"]=>
>   string(11) "18236447981"
>   ["bytes_written"]=>
>   string(11) "14350735133"
>   ["limit_maxbytes"]=>
>   string(10) "2147483648"
> }
> 
> 
>