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
memgraph
Memgraph is an ACID compliant high performance transactional distributed in-memory graph database featuring runtime native query compiling, lock free data structures, multi-version concurrency control and asynchronous IO.
dependencies
Memgraph can be compiled using any modern c++ compiler. It mostly relies on the standard template library, however, some things do require external libraries.
Some code contains linux-specific libraries and the build is only supported on a 64 bit linux kernel.
- linux
- clang 3.8 (good c++11 support, especially lock free atomics)
- antlr (compiler frontend)
- cppitertools
- fmt format
- google benchmark
- google test
- glog
- gflags