Overview

Module riak_core_bucket_type

• Description
• Data Types
• Function Index
• Function Details

Description

Bucket Types allow groups of buckets to share configuration details. Each bucket belongs to a type and inherits its properties. Buckets can override the properties they inherit using riak_core_bucket. The "Default Bucket Type" always exists. The Default Type's properties come from the riak_core default_bucket_props application config, so the Default Type and its buckets continue to act as they had prior to the existence of Bucket Types.

Unlike Buckets, Bucket Types must be explicitly created. In addition, types support setting some properties only on creation (via riak_core_bucket_props:validate/4). Since, types are stored using riak_core_metadata, in order to provide safe creation semantics the following invariant must be satisfied: all nodes in the cluster either see no type or a single version of the type for the lifetime of the cluster (nodes need not see the single version at the same time). As part of ensuring this invariant, creation is a two-step process:

1. The type is created and is inactive. To the node an inactive type does not exist 2. When the creation has propogated to all nodes, the type may be activated. As the activation propogates, nodes will be able to use the type

The first step is performed using create/2. The second by activate/1. After the type has been activated, some properties may be updated using update/2. All operations are serialized through riak_core_claimant except reading bucket type properties with get/1.

Bucket types can be in one of four states. The state of a type can be queried using status/1.

1. undefined - the type has not been created 2. created - the type has been created but has not propogated to all nodes 3. ready - the type has been created and has propogated to all nodes but has not been activated 4. active - the Bucket Type has been activated, but the activation may not have propogated to all nodes yet

In order for the invariant to hold, additional restrictions are placed on the operations, generally and based on the state of the Bucket Type. These restrictions are in-place to ensure safety during cases where membership changes or node failures change the riak_core_claimant to a new node -- ensuring concurrent updates do not break the invariant.

* calling create/1 multiple times before a Bucket Type is active is allowed. The newer creation will supersede any previous ones. In addition, the type will be "claimed" by the riak_core_claimant node writing the property. Future calls to create/1 must be serialized through the same claimant node or the call will not succeed. In the case where the claimed type fails to propogate to a new claimant during a a failure the potential concurrent update is resolved with last-write-wins. Since nodes can not use inactive types, this is safe. * A type may only be activated if it is in the ready state. This means all nodes must be reachable from the claimant * create/1 will fail if the type is active. Activation concurrent with creation is not possible due to the previous restriction * update/1 will fail unless the type is updated. update/1 does not allow modifications to properties for which the invariant must hold (NOTE: this is up to the implementor of the riak_core bucket_validator).

Data Types

bucket_type()

bucket_type() = binary()

bucket_type_props()

bucket_type_props() = riak_core_bucket:properties()

Function Index

Function Details

activate/1

Activate the type. This will succeed only if the type is in the ready state. Otherwise, an error is returned.

all_n/0

iterate over bucket types and find any active buckets.

create/2

Create the type. The type is not activated (available to nodes) at this time. This function may be called arbitratily many times if the claimant does not change between calls and the type is not active. An error will also be returned if the properties are not valid. Properties not provided will be taken from those returned by

See also: defaults/0.

defaults/0

The hardcoded defaults for all bucket types.

defaults/1

The hardcoded defaults for the legacy, default bucket type. These find their way into the default_bucket_props environment variable

fold/2

Fold over all bucket types, storing result in accumulator

get/1

Return the properties associated with the given bucket type.

iterator/0

Return an iterator that can be used to walk through all existing bucket types and their properties

itr_close/1

itr_done/1

Returns true if there are no more bucket types to iterate over

itr_next/1

Advance the iterator to the next bucket type. itr_done/1 should always be called before this function

itr_value/1

Returns the type and properties that the iterator points too. Any siblings, are resolved at this time. itr_done/1 should be checked before calling this function.

property_hash/2

Returns a hash of a specified set of bucket type properties whose values may have implications on the treatment or handling of buckets created using the bucket type.

property_hash/3

reset/1

Reset the properties of the bucket. This only affects properties that can be set using update/2 and can only be performed on an active type.

status/1

Returns the state the type is in.

update/2

Update an existing bucket type. Updates may only be performed on active types. Properties not provided will keep their existing values.

Overview

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