Message-ID: <1241171443.2548.1485845413558.JavaMail.confluence@ip-10-127-227-164> Subject: Exported From Confluence MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_Part_2547_102314309.1485845413558" ------=_Part_2547_102314309.1485845413558 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Location: file:///C:/exported.html Persistence cache configuration

Persistence cache configuration


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Introduction

Tech Note

Current implementation uses a caching library called Stash (= via StashBundle). Stash supports the followi= ng cache backends: FileSystem, Memcache, APC,= Sqlite, Redis and BlackHole.

Use of Memcached (or experimentally using Redis) is a requirement fo= r use in Clustering setup. For an overview of this feature, see Clustering. 

When eZ Platform changes to another PSR-6 based cache system in the future,= then configuration documented below will change.

Cache service

The cache system is exposed as a "cache" service, and can be reused by a= ny other service as described on the Using Cache service page.

Configuration

By default, configuration is currently using FileSystem= , with %kernel.cache_dir%/stash to store cache files.

The configuration is placed in app/config/config.yml and lo= oks like this:

Default config.yml
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stash:
    caches:
        default:
            drivers:
                - FileSystem
            inMemory: true
            registerDoctrineAdapter: false
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Note for "inMemory" cache with long running scripts

Use inMemory with caution, and avoid it completely for long= running scripts for the following reasons:

  • It does not have any limits, so can result in the application running o= ut of PHP memory.
  • Its cache pool is by design a PHP variable and is not shared acro= ss requests/processes/servers, so data becomes stale if any other concurren= t activity happens towards the repository.

Multi reposit= ory setup

In ezplatform.yml you can specify which cache pool you want= to use on a siteaccess or sitegroup level. The following example shows use= in a sitegroup:

ezplatform.yml site group setting
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ezpublish:
    system:
        # "site_group" refers to the group configured in site access
        site_group:
            # "default" refers to the cache pool, the one configured on sta=
sh.caches above
            cache_pool_name: "default"
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One cache pool for each repository

If your installation has several repositories=20 (databases), make sure every group of sites using different r= epositories also uses a different cache pool.

Sta= sh cache backend configuration

General settings

To check which cache settings are available for your installation, run t= he following command in your terminal:

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php app/console config:dump-reference stash
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FileSystem=

This cache backend uses the local filesystem, by default the Symfony cac= he folder. As this is per server, it does not support multi se= rver (cluster) setups!=

We strongly discourage you from storing cache files on NFS= , as it defeats the purpose of the cache: speed.

Availab= le settings

path
 The path where the cache is placed; default is <= code>%kernel.cache_dir%/stash, effectively app/cache/<env&g= t;/stash 
dirSplit
 Number of times the cache key shou= ld be split up to avoid having too many files in each folder; default is 2.= 
filePermissions
 The permissions of the cache file;= default is 0660. 
dirPermissions
 The permission of the cache file d= irectories (see dirSplit); default is 0770. 
memKeyLimit

Limit on how many key to path e= ntries are kept in memory during execution at a time to avoid having to rec= alculate the path on key lookups; default is 200.

 
keyHashFunction
 Algorithm used for creating paths;= default is md5. Use crc32 on Windows to avoid path length issues.

Issues with Microsoft Windows

If you are using a Windows OS, you may encounter an issue regarding long paths for cache directory name. The paths are long becaus= e Stash uses md5 to generate unique keys that are sanitized really quickly.=

Solution is to change the hash algorithm used by Stash.=

Specifying key hash function
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stash:
    caches:
        default:
            drivers:
                - FileSystem
            inMemory: true
            registerDoctrineAdapter: false
            FileSystem:
                keyHashFunction: 'crc32'
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This configuration is only recommended for Windows users.

Note: You can also define the path where you wan= t the cache files to be generated to be able to get even shorter system pat= h for cache files.

 

FileSystem cache backend troubleshooting

By default, Stash Filesystem cache backend stores cache to a sub-folder = named after the environment (i.e. app/cache/dev, app/cac= he/prod). This can lead to the following issue: if different environ= ments are used for operations, persistence cache (manipulating content, mos= tly) will be affected and cache can become inconsistent.

To prevent this, there are 2 solutions:

 

1. Manual

Always use the same environment, for web, command = line, cronjobs etc.

2 . Share stash cache across environments

Either by using another Stash cache backend, or by setting Stash to use = a shared cache folder that does not depend on the environment.

In ezplatform.yml:

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stash:
    caches:
        default:
            FileSystem:
                path: "%kernel.root_dir%/cache/common"
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This will store stash cache to app/cache/common.

APC & APCu

This cache backend is using shard memory with APC's user cache feature. = As this is per server, it does not support multi server (cluster) setups.

Not supported because of following limitation

As APC(u) user cache is not shared between processes, it is not possible= to clear the user cache from CLI, even if you set apc.enable_cli to On. That is why publishing= content from a command line script won't let you properly clear SPI Persis= tence cache.

Please also note that the default value for apc.shm_size is 128MB. However, 256MB is recommended for APC to work properly. For mo= re details please refer to the APC configuration manual.

 

Available settings

ttl The time to live of the cache in seconds; defaul= t is 500 (8.3 minutes)
namespace A namespace to prefix cache keys w= ith to avoid key conflicts with other eZ Platform sites on same eZ Platform= installation; default is null.

Memcache(d)

This cache backend is using Memcached, a distributed caching solution. This is the only supported cache solution for multi server (cluster) setups!

Note

Stash supports both the php-memcache and php-memcached exte= nsions. However only php-memcached is officially supported= as php-memcache is missing many features and is less stable.

servers

Array of Memcached servers, wit= h host/IP, port and weight

server: Host= or IP of your Memcached server
port: Port= that Memcached is listening to (defaults to 11211)
weight= : Weight of the server, when using several Memcached server= s
prefix_key<= /code> A namespace to prefix cache = keys with to avoid key conflicts with other eZ Platform sites on same eZ Pl= atform installation (default is an empty string).
Must be = the same on all servers with the same installation. See Memcached = prefix_key option * 
compression= default true. See Memcached compression op= tion * 
libketama_compatible= default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-libketama-compatible" class=3D"external-link" rel=3D"nofollow">= See Memcached libketama_compatible option * 
buffer_writes default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-buffer-writes" class=3D"external-link" rel=3D"nofollow">See Mem= cached buffer_writes option * 
binary_protocol default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-binary-protocol" class=3D"external-link" rel=3D"nofollow">See M= emcached binary_protocol option* 
no_block default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-no-block" class=3D"external-link" rel=3D"nofollow">See Memcache= d no_block option * 
tcp_nodelay= default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-tcp-nodelay" class=3D"external-link" rel=3D"nofollow">See Memca= ched tcp_nodelay option * 
connection_timeout default 1000. See= Memcached connection_timeout option * 
retry_timeout default 0. See Mem= cached retry_timeout option * 
send_timeout default 0. See Memcache= d send_timeout option * 
recv_timeout

default 0. See Memca= ched recv_timeout option * 
poll_timeout default 1000. See Memca= ched poll_timeout option * 
cache_lookups default false. <= a href=3D"http://www.php.net/manual/en/memcached.constants.php#memcached.co= nstants.opt-cache-lookups" class=3D"external-link" rel=3D"nofollow">See Mem= cached cache_lookups option * 
server_failure_limit= default 0. See = PHP Memcached documentation * 
socket_send_size
See Memcached socket_send_size option= *
socket_recv_size See Memcached socket_recv_size option= *
serializer See Memcached serializer option *
hash= See Memcached hash option *
distribution<= /strong>

Specifies the method of distrib= uting item keys to the servers. See Memcached distribution option *

 

* All settings except servers are only ava= ilable with memcached PHP extension. For more information on these settings= and which version of php-memcached they are available in, see: = ;http://php.net/Memcached
=

 

When using Memcache cache backend, you may use inMemory to redu= ce network traffic as long as you are aware of its limitations mentioned ab= ove.

Example with M= emcache

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stash:
    caches:
        default:
            drivers: [ Memcache ]
            inMemory: true
            registerDoctrineAdapter: false
            Memcache:
                prefix_key: ezdemo_
                retry_timeout: 1
                servers:
                    -
                        server: 127.0.0.1
                        port: 11211
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Connection errors issue

If memcached does display connection errors when using the default (asci= i) protocol, then switching to binary protocol (in the stash configurat= ion and memcached daemon) should resolve the issue.

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