Relay provides several configuration directives and the relay.ini file is easily located by running:

php --ini

It’s strongly recommended to set the relay.maxmemory, relay.eviction_policy and relay.databases directives. If you’re running a licensed binary, be sure to set the relay.key and relay.environment as well.

Memory limits

Relay will allocate what relay.maxmemory is set to when PHP starts, even if no relay.key. However if no valid license was set, after 60 minutes of runtime, Relay will downsize the allocated memory to its hard limit of 16 MB.

Disabling the cache

Sometimes you may wish to install the Relay extension, but not have it allocate memory, either because you want to only use it as a faster alternative to PhpRedis, or to keep it dormant for future use.

You may disable all in-memory caching and memory allocation by setting:

relay.maxmemory = 0

Configuration directives

Directive Default Description
relay.key Relay license key. Without a license key Relay will throttle to 16MB memory one hour after startup.
relay.environment development The environment Relay is running in. Supported values: production, staging, testing, development
relay.maxmemory 32M How much memory Relay allocates on startup. This value can either be a number like 134217728 or a unit (e.g. 128M) like memory_limit. Relay will allocate at least 16M for overhead structures. Set to 0 to disable in-memory caching and use as client only.
relay.maxmemory_pct 95 At what percentage of used memory should Relay start evicting keys.
relay.eviction_policy noeviction How should relay evict keys. This has been designed to mirror Redis’ options and we currently support noeviction, lru, and random.
relay.eviction_sample_keys 128 How many keys should we scan each time we process evictions.
relay.default_pconnect 1 Default to using a persistent connection when calling connect().
relay.databases 16 The number of databases Relay will create per in-memory cache. This setting should match the databases setting in your redis.conf.
relay.max_endpoint_dbs 32 The maximum number of PHP workers that will have their own in-memory cache. While each PHP worker will have its own connection to Redis, not all workers need their own in-memory cache and can be read-only workers. This setting is per connection endpoint (distinct Redis connections), e.g. connecting to two separate instances will double the workers.
relay.initial_readers 128 The number of epoch readers allocated on startup.
relay.invalidation_poll_freq 5 How often (in microseconds) Relay should proactively check the connection for invalidation messages from Redis.
relay.loglevel off Whether Relay should log debug information. Supported levels: debug, verbose, error, off
relay.logfile /tmp/relay.log The path to the file in which information should be logged, if logging is enabled.