Nebulex.Adapters.Local.Generation (Nebulex v2.0.0) View Source
Generational garbage collection process.
The generational garbage collector manage the heap as several sub-heaps,
known as generations, based on age of the objects. An object is allocated
in the youngest generation, sometimes called the nursery, and is promoted
to an older generation if its lifetime exceeds the threshold of its current
generation (defined by option :gc_interval). Everytime the GC runs
(triggered by :gc_interval timeout), a new cache generation is created
and the oldest one is deleted.
The only way to create new generations is through this module (this server
is the metadata owner) calling new/2 function. When a Cache is created,
a generational garbage collector is attached to it automatically,
therefore, this server MUST NOT be started directly.
Options
These options are configured through the Nebulex.Adapters.Local adapter:
:gc_interval- If it is set, an integer > 0 is expected defining the interval time in milliseconds to garbage collection to run, delete the oldest generation and create a new one. If this option is not set, garbage collection is never executed, so new generations must be created explicitly, e.g.:MyCache.new_generation(opts).:max_size- If it is set, an integer > 0 is expected defining the max number of cached entries (cache limit). If it is not set (nil), the check to release memory is not performed (the default).:allocated_memory- If it is set, an integer > 0 is expected defining the max size in bytes allocated for a cache generation. When this option is set and the configured value is reached, a new cache generation is created so the oldest is deleted and force releasing memory space. If it is not set (nil), the cleanup check to release memory is not performed (the default).:gc_cleanup_min_timeout- An integer > 0 defining the min timeout in milliseconds for triggering the next cleanup and memory check. This will be the timeout to use when either the max size or max allocated memory is reached. Defaults to10_000(10 seconds).:gc_cleanup_max_timeout- An integer > 0 defining the max timeout in milliseconds for triggering the next cleanup and memory check. This is the timeout used when the cache starts and there are few entries or the consumed memory is near to0. Defaults to600_000(10 minutes).
Link to this section Summary
Functions
Returns a specification to start this module under a supervisor.
Removes or flushes all entries from the cache (including all its generations).
A convenience function for retrieving the state.
Returns the list of the generations in the form [newer, older].
Returns the memory info in a tuple form {used_mem, total_mem}.
Creates a new cache generation. Once the max number of generations is reached, when a new generation is created, the oldest one is deleted.
Returns the newer generation.
Reallocates the block of memory that was previously allocated for the given
server_ref with the new size. In other words, reallocates the max memory
size for a cache generation.
Resets the timer for pushing new cache generations.
Returns the PID of the GC server for the given server_ref.
Starts the garbage collector for the build-in local cache adapter.
Link to this section Types
Specs
opts() :: Nebulex.Cache.opts()
Specs
Specs
t() :: %Nebulex.Adapters.Local.Generation{
allocated_memory: term(),
backend: term(),
backend_opts: term(),
gc_cleanup_max_timeout: term(),
gc_cleanup_min_timeout: term(),
gc_cleanup_ref: term(),
gc_heartbeat_ref: term(),
gc_interval: term(),
max_size: term(),
meta_tab: term(),
stats_counter: term()
}
Link to this section Functions
Returns a specification to start this module under a supervisor.
See Supervisor.
Specs
delete_all(server_ref()) :: integer()
Removes or flushes all entries from the cache (including all its generations).
Example
Nebulex.Adapters.Local.Generation.delete_all(MyCache)Specs
get_state(server_ref()) :: t()
A convenience function for retrieving the state.
Specs
list(server_ref()) :: [:ets.tid()]
Returns the list of the generations in the form [newer, older].
Example
Nebulex.Adapters.Local.Generation.list(MyCache)Specs
memory_info(server_ref()) :: {used_mem :: non_neg_integer(), total_mem :: non_neg_integer()}
Returns the memory info in a tuple form {used_mem, total_mem}.
Example
Nebulex.Adapters.Local.Generation.memory_info(MyCache)Specs
new(server_ref(), opts()) :: [atom()]
Creates a new cache generation. Once the max number of generations is reached, when a new generation is created, the oldest one is deleted.
Options
:reset_timer- Indicates if the poll frequency time-out should be reset or not (default: true).
Example
Nebulex.Adapters.Local.Generation.new(MyCache)
Nebulex.Adapters.Local.Generation.new(MyCache, reset_timer: false)Specs
newer(server_ref()) :: :ets.tid()
Returns the newer generation.
Example
Nebulex.Adapters.Local.Generation.newer(MyCache)Specs
realloc(server_ref(), pos_integer()) :: :ok
Reallocates the block of memory that was previously allocated for the given
server_ref with the new size. In other words, reallocates the max memory
size for a cache generation.
Example
Nebulex.Adapters.Local.Generation.realloc(MyCache, 1_000_000)Resets the timer for pushing new cache generations.
Example
Nebulex.Adapters.Local.Generation.reset_timer(MyCache)Specs
server(server_ref()) :: pid()
Returns the PID of the GC server for the given server_ref.
Example
Nebulex.Adapters.Local.Generation.server(MyCache)Specs
start_link(opts()) :: GenServer.on_start()
Starts the garbage collector for the build-in local cache adapter.