Async POC #6317
Async POC #6317
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Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
src/server/string_family.cc
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| boost::intrusive_ptr<Transaction> keepalive{cmnd_cntx->tx}; | ||
| auto replier = [mget_results, mget_resp, cmnd_cntx, keepalive](SinkReplyBuilder* builder) { |
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issues:
- Use a move-only functor so we can use unique_ptr
- Automatically implement a keepalive mechanism for the transaction
| return (prev_state & ASYNC_REPLY_DONE) != 0; | ||
| } | ||
| bool IsReady() const; // If deferred is ready | ||
| bool OnCompletion(util::fb2::detail::Waiter* waiter); |
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| // Update head state and subscribe to updates if its not ready | ||
| if (parsed_head_ && parsed_head_ != parsed_to_execute_ && !head_ready) | ||
| head_ready |= parsed_head_->OnCompletion(&head_waiter); |
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Please write explanation here what exactly we do here. It's gentle, so I prefer we have comments than going through low-level code to understand
| task.blocker->OnCompletion(waiter); | ||
| return false; | ||
| }}; | ||
| return visit(ov, reply_); |
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how the access to reply_ is synchronized between threads?
before, with state_ one a single thread could access reply_payload.
now I see OnCompletion is called from the io thread but you also write into reply_ from the shard thread
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I never write into reply from the shard thread, its either assigned to the return value of the handler or set to the callback that will reply
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Ok, I will need to see SET command I guess - how it propagates the Stored reply from the shard thread.
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it won't propagate from the shard thread, it will work via a replier
Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
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Related to #6314