A, Actor Introduction
Actor is a concurrency model is an alternative to shared memory concurrency model.
Shortcoming shared memory model:
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Shared memory model using a variety of locks to solve the state competition, poor performance and make coding is complicated and prone to error.
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Shared memory is limited to a single node server resource limitations.
Actor model advantages:
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To communicate messages between threads, message sequence single thread, there is no competition status.
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Way to communicate a message, you can easily set up a cluster.
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The State and Behavior bindings, better control of the state.
Glossary:
Mailbox: can be understood as first in first out queue, and the cache is responsible for receiving messages delivered.
State: state information, such as the user's account balance information.
Behavior: responsible for order processing Mailbox messages, such as debit messages, arrival messages, check your balance messages.
Two, Orleans Introduction
Actor .Net Orleans is a foundation to maintain cross-platform open-source framework, Virtual Actor original concept, support for distributed clusters.
Project Address: http://dotnet.github.io/orleans/
It has the following advantages:
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Access to objects Actor, consistent with object-oriented habits.
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Proposed the concept of the Virtual Actor, fine-grained access ID by Actor, Actor can carry tens of millions of objects.
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The Stateful support, buffer layer can replace more precise control of the memory state, reducing the pressure on the database.
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High-performance, single Actor can support 100,000 + in QPS.
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Activation transparent, Actor of visitors is permanent, but also provide complete life cycle control, easy to expand.
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Native support for clusters, but Actor location transparency, visitors do not need to concern Actor running load will be scheduled according to the node where the node cluster.
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Offers a variety of support cluster, the cluster is very easy to deploy, support AdoNet, Zookeeper, K8s, SF and so on.
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It provides a complete solution for unit testing, unit testing easy.
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It provides a perfect monitoring tool that detailed monitoring indicators.
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Based on .net core, supports a variety of platforms.
Glossary:
Silo: a node in the cluster, Grains responsible for maintaining the current node.
SiloGateway: Each node exists, is responsible for maintaining the cluster status and forwards the request.
Grain: equivalent Actor, identified by ID + Interface.
Client: Grain used to access the cluster of client tools.
Three, Ray introduced
Ray Actor model constructed based on event-based distributed ultimately traceable high performance consistency frame, the traditional split complicated distributed transaction processing flow by way of the linear event-driven, performance and higher throughput, more responsive.
Ray offers state maintenance, event publish / subscribe, such as power control, distributed transactions and other modules, and built a distributed ID, distributed lock, lock the weight distributed services.
Ray provide superior performance, can achieve a single Actor 20000 / s events.
Project Address: https://github.com/RayTale/Ray
Glossary:
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State (State): aggregate data memory.
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Event (Event): change of status information.
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EventBus: providing events and send event consumer subscriptions.
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Idempotence: to ensure event delivery times will not cause an abnormal state, such as transfer event A chart on multiple service B, but B will only increase once the balance.
Ray's final consistency principle transfer
A user calls A method of transferring accounts Actor of transfer funds, check balances carried Actor account A state based on memory, if the balance is insufficient, the direct cause of the failure is returned, if the check is to produce a successful transfer Event (recording target account Id, transfer amount , the remaining balance) and persisted, and then transmitted to modify memory state EventBus. EventBus a subscriber balance reading event information repository A modified account transfers and bill inserted into the bill a table, call another subscriber account Actor arrival method B according to event information based on, will produce a B account Actor arrival Event (arrival record amount, FromId, the remaining balance) and persisted, and then transmitted to modify memory state EventBus, EventBus arrival of a subscriber billing according to the balance of the read event information modification repository and inserted into the B accounts in a billing table .