SuperCache.Partition.Holder (SuperCache v1.3.0)

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Registry for partition ETS table names.

Maintains a mapping from partition index (integer) to the corresponding ETS table atom. The mapping is stored in a :protected ETS table owned by this GenServer so that:

  • Reads are lock-free (:read_concurrency).
  • The table survives crashes as long as this GenServer is alive.
  • Multiple processes can look up partitions concurrently without blocking each other.

Lifecycle

  1. On application start, Partition.start/1 calls set_num_partition/1 and set/1 for each index to populate the registry.
  2. During runtime, get/1 and get_all/1 are used by the routing layer to resolve partition tables.
  3. On shutdown, stop/0 clears the registry.

Example

SuperCache.Partition.Holder.set_num_partition(4)
SuperCache.Partition.Holder.set(0)
SuperCache.Partition.Holder.get(0)
# => :"SuperCache.Storage.Ets_0"

Summary

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

clean()

Clears all partition registrations from the ETS table.

get(order)

Look up the ETS table atom for a given partition index.

get_all()

Return all registered partition ETS table atoms.

set(order)

Register a partition index with its corresponding ETS table name.

set_num_partition(num)

Store the total number of partitions in the registry.

start_link(opts \\ [])

Starts the Partition.Holder GenServer and its owned ETS table.

stop()

Stops the Partition.Holder GenServer.

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

clean()

@spec clean() :: true

Clears all partition registrations from the ETS table.

Does NOT delete the ETS table itself — only removes its contents.

get(order)

@spec get(non_neg_integer()) :: atom() | nil

Look up the ETS table atom for a given partition index.

Reads directly from the ETS table — no GenServer hop. Raises if the index has not been registered.

Examples

SuperCache.Partition.Holder.get(0)
# => :"SuperCache.Storage.Ets_0"

get_all()

@spec get_all() :: [atom()]

Return all registered partition ETS table atoms.

Filters out non-partition entries (such as :num_partition).

set(order)

@spec set(non_neg_integer()) :: :ok

Register a partition index with its corresponding ETS table name.

The table name is derived from the configured :table_prefix and the given order (index). For example, with prefix "SuperCache.Storage.Ets" and order 2, the table name will be :"SuperCache.Storage.Ets_2".

set_num_partition(num)

@spec set_num_partition(pos_integer()) :: :ok

Store the total number of partitions in the registry.

Used by Partition.get_num_partition/0 to resolve the partition count without a GenServer hop.

start_link(opts \\ [])

@spec start_link(keyword()) :: :ignore | {:error, any()} | {:ok, pid()}

Starts the Partition.Holder GenServer and its owned ETS table.

stop()

@spec stop() :: :ok

Stops the Partition.Holder GenServer.

The ETS table will be deleted when the GenServer terminates.