1e0ac8ab8f
Summary: My dear fellow Memgraphians. It's friday afternoon, and I am as ready to pop as WAL is to get reviewed... What's done: - Vertices and Edges have global IDs, stored in `VersionList`. Main storage is now a concurrent map ID->vlist_ptr. - WriteAheadLog class added. It's based around buffering WAL::Op objects (elementraly DB changes) and periodically serializing and flusing them to disk. - Snapshot recovery refactored, WAL recovery added. Snapshot format changed again to include necessary info. - Durability testing completely reworked. What's not done (and should be when we decide how): - Old WAL file purging. - Config refactor (naming and organization). Will do when we discuss what we want. - Changelog and new feature documentation (both depending on the point above). - Better error handling and recovery feedback. Currently it's all returning bools, which is not fine-grained enough (neither for errors nor partial successes, also EOF is reported as a failure at the moment). - Moving the implementation of WAL stuff to .cpp where possible. - Not sure if there are transactions being created outside of `GraphDbAccessor` and it's `BuildIndex`. Need to look into. - True write-ahead logic (flag controlled): not committing a DB transaction if the WAL has not flushed it's data. We can discuss the gain/effort ratio for this feature. Reviewers: buda, mislav.bradac, teon.banek, dgleich Reviewed By: dgleich Subscribers: mtomic, pullbot Differential Revision: https://phabricator.memgraph.io/D958
20 lines
379 B
C++
20 lines
379 B
C++
#pragma once
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#include <chrono>
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namespace utils {
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// This class is threadsafe.
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class Timer {
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public:
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/** Time elapsed since creation. */
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std::chrono::duration<double> Elapsed() const {
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return std::chrono::steady_clock::now() - start_time_;
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}
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private:
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std::chrono::time_point<std::chrono::steady_clock> start_time_ =
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std::chrono::steady_clock::now();
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};
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};
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