7f1c7a46cc
Summary: 1. added distributed tests, currently only one can be run (TODO) 2. usability changes: add Close() to Subscription 3. EventStream::Subscription -> Subscription 4. Add Subscription to ChainOnce 5. Added README.md conventions5 Reviewers: sasa.stanko Reviewed By: sasa.stanko Subscribers: pullbot, buda Differential Revision: https://phabricator.memgraph.io/D701
34 lines
1.5 KiB
Markdown
34 lines
1.5 KiB
Markdown
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# distributed memgraph
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This subdirectory structure implements distributed infrastructure of Memgraph.
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## Terminology
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* Memgraph Node Id (mnid): a machine (processs) that runs a (distributed) Memgraph program.
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* Node: a computer that performs (distributed) work.
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* Vertex: an abstract graph concept.
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* Reactor: a unit of concurrent execution, lives on its own thread.
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* Channel: a (one-way) communication abstraction between Reactors. The reactors can be on the same machine or on different processes.
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* Message: gets sent through channels. Must be serializable if sent via network layer (library: cereal).
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* Event: arrival of a (subclass of) Message. You can register callbacks. Register exact callbacks (not for derivated/subclasses).
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* EventStream: read-end of a channel, is owned by exactly one Reactor/thread.
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* ChannelWriter: write-end of a channel, can be owned (wrote into) by multiple threads.
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## Ownership:
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* System, Distributed are singletons. They should be always alive.
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* ChannelWriter (write-end) should be lightweight and can be copied arbitrarily.
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* EventStream (read-end) should never be written by anyone except the owner (the reactor that created it).
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## Code Conventions
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* Locked: A method having a Locked... prefix indicates that you
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have to lock the appropriate mutex before calling this function.
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* ALWAYS close channels. You will memory leak if you don't.
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Reactor::CloseChannel or Subscription::Close will do the trick.
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## Dependencies
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* cereal
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* <other memgraph dependencies> |