engine-params.org

EP Parameters

1 Configuring the Engine

Engine parameters may be specified using the -e option to memcached. These parameters control various aspects of the behavior of the engine.

For example, if you would like to store your database in /data/base and prevent it from having objects larger than 1MB, you would run memcached like this:

memcached -E ep.so -e 'dbfile=/data/base;max_item_size=1048576'

2 Parameters for the EP Engine

key	type	descr
config_file	string	Path to additional parameters.
dbname	string	Path to on-disk storage.
ht_locks	int	Number of locks per hash table.
ht_size	int	Number of buckets per hash table.
initfile	string	Optional SQL script to run after opening DB
postInitfile	string	Optional SQL script to run after all DB
		shards and statements have been initialized
max_item_size	int	Maximum number of bytes allowed for an item.
tap_backlog_limit	int	Max number of items allowed in a tap backfill
max_size	int	Max cumulative item size in bytes.
mem_high_wat	int	Automatically evict when exceeding this size.
mem_low_wat	int	Low water mark to aim for when evicting.
min_data_age	int	Minimum data stability time before persist.
queue_age_cap	int	Maximum queue time before forcing persist.
tap_id	string	Local tap identifier for remote peer.
tap_idle_timeout	int	Tap client idle timeout.
tap_keepalive	int	Seconds to hold open named tap connections.
tap_peer	string	Upstream server to contact.
vb0	bool	If true, start with an active vbucket 0
waitforwarmup	bool	Whether to block server start during warmup.
warmup	bool	Whether to load existing data at startup.
expiry_window	int	expiry window to not persist an object
		that is expired (or will be soon)
exp_pager_stime	int	Sleep time for the pager that purges expired
		objects from memory and disk
failpartialwarmup	bool	If false, continue running after failing to
		load some records.
db_shards	int	Number of shards for db store