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Merged
merged 69 commits into from
May 12, 2025
Merged

Scheduler based on priority queue and communication stack improvements #2567

merged 69 commits into from
May 12, 2025
+2,126 −935

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andrejtonev
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@andrejtonev andrejtonev commented Dec 20, 2024 •
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Bolt worker pool has been separated from the boost::asio communication stack
While the communication still relies on boost::asio, it is only used to queue tasks onto the new scheduler
PriorityThreadPool is a new class that can order tasks by priority and execute them on N threads + 1 sidecar thread
The sidecar thread is used for high priority tasks only and is a workaround because tasks cannot yield at the moment
This allows us to never block a connection and to always execute selection of high priority queries
Deprecated --bolt-session-inactivity-timeout flag
New hidden flag --scheduler which allows user to select between priority_queue and asio
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andrejtonev commented Dec 20, 2024 •
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    • New bolt work scheduler based on a priority queue with a sidecar channel for high priority queries. Users should never see a blocked database due to heavy load. Users can now run specific high priority queries even under heavy loads (example: SHOW TRANSACTIONS). 2567
  • Scheduler docs documentation#1302
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@andrejtonev andrejtonev self-assigned this Dec 20, 2024
@andrejtonev andrejtonev added feature feature Docs needed Docs needed CI -build=community -test=core Run community build and core tests on push CI -build=coverage -test=core Run coverage build and core tests on push CI -build=debug -test=core Run debug build and core tests on push CI -build=debug -test=integration Run debug build and integration tests on push CI -build=release -test=e2e Run release build and e2e tests on push CI -build=release -test=stress Run release build and stress tests on push labels Dec 20, 2024
@gitbuda gitbuda added this to the mg-v3.0.0 milestone Dec 30, 2024
@andrejtonev andrejtonev added the CI -build=release -test=benchmark Run release build and benchmark on push label Jan 3, 2025
Ignition
Ignition requested changes Jan 15, 2025
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@andrejtonev andrejtonev force-pushed the custom_worker_pool branch 2 times, most recently from 9284d5c to 8f20e94 Compare January 23, 2025 10:20
@gitbuda gitbuda modified the milestones: mg-v3.0.0, mg-v3.1.0 Jan 27, 2025
@andrejtonev andrejtonev removed CI -build=community -test=core Run community build and core tests on push CI -build=coverage -test=core Run coverage build and core tests on push CI -build=debug -test=core Run debug build and core tests on push CI -build=debug -test=integration Run debug build and integration tests on push CI -build=release -test=e2e Run release build and e2e tests on push CI -build=release -test=stress Run release build and stress tests on push labels Feb 16, 2025
@andrejtonev andrejtonev force-pushed the custom_worker_pool branch 3 times, most recently from 5561953 to ad24b0a Compare February 17, 2025 21:03
@andrejtonev
Code cleanup 1
222f9aa 
Moved worker pool to memgraph.cpp from Server Removed pool's pointer from ServerContext and Session SessionContext now has pool's pointer and a function to help add tasks Removed unused code from ChunkedDecoderBuffer Comments and general cleanup
@andrejtonev
Code cleanup 2
bd21221 
Removed TypedValueResultStreamBase and DecodeValue	unused due to MesssageRecord split Prepare doesn't assert but throws on missing parsed_res_	Should never happen, just in case General celan up
@andrejtonev
Code cleanup 3
9b93c40 
worker pool AwaitShutdown better names and general cleanup
@andrejtonev
Code cleanup 4
c7647e1 
Moved SimpleBarrier to its own header	Redesign using wait and notify	Unit tests Moved yielder to its own header and unified with RWSpinLock one
@andrejtonev
SimpleBarrier notify on bool (single possible value)
ece9525
@andrejtonev
Code cleanup4
0712343 
Hot threads reorganized into a class HotMaks unit tests
@andrejtonev
Code cleanup 5
711d09d 
Bugfix in sched_mon not detecting last_task (introduced in prev cleanup) HIGH only specific query types unit tests
andrejtonev and others added 2 commits April 29, 2025 21:30
@andrejtonev
Merge branch 'master' into custom_worker_pool
9804f16
@andrejtonev
Code cleanup 6
9d6fa28 
Bugfix: Worker destoryed before safe	- Worker was part of the operator() which exits on shutdown	- Every worker has a vector of other workers	- Worker can be destoryed only after each thread exited	- workers_ is now a unique_ptr unit test fix
@andrejtonev andrejtonev changed the title WIP: Communication stack improvements Scheduler based on priority queue and communication stack improvements May 5, 2025
@andrejtonev andrejtonev marked this pull request as ready for review May 5, 2025 12:06
@andrejtonev
Added scheduler selector
bd9b333 
New command-line HIDDEN flag `scheduler` New e2e test
@andrejtonev andrejtonev force-pushed the custom_worker_pool branch from 306a73d to bd9b333 Compare May 5, 2025 15:38
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Quality Gate Passed Quality Gate passed

Issues
11 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud
@andrejtonev andrejtonev added this pull request to the merge queue May 12, 2025
Merged via the queue into master with commit 1af5a81 May 12, 2025
17 checks passed
@andrejtonev andrejtonev deleted the custom_worker_pool branch May 12, 2025 12:54
@andrejtonev andrejtonev mentioned this pull request Jun 2, 2025
Merged
11 tasks
@gitbuda gitbuda mentioned this pull request Jun 3, 2025
Merged
16 tasks
@andrejtonev andrejtonev linked an issue Jun 26, 2025 that may be closed by this pull request
Implement a "side car / sidecar thread" #1084
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@gitbuda gitbuda mentioned this pull request Jun 26, 2025
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CI -build=community -test=core Run community build and core tests on push CI -build=coverage -test=core Run coverage build and core tests on push CI -build=debug -test=integration Run debug build and integration tests on push CI -build=jepsen -test=core Run jepsen build and core tests on push CI -build=release -test=benchmark Run release build and benchmark on push CI -build=release -test=e2e Run release build and e2e tests on push CI -build=release -test=query_modules Run release build and query modules tests on push CI -build=release -test=stress Run release build and stress tests on push Docs needed Docs needed feature feature

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@andrejtonev @Ignition @gitbuda