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
Summary:
Use sigaction to register signal handlers.
This is preferred over `signal` function, according to `man 3p signal`.
Add global sig_atomic_t flag when shutting down.
Block other signal handlers when shutting down.
Reviewers: mislav.bradac, mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D943
Summary:
Remove name from GraphDb.
Take GraphDb in query test macros instead of accessor.
Add is_accepting_transactions flag to GraphDb.
Reviewers: mislav.bradac, florijan, mferencevic
Reviewed By: mislav.bradac
Subscribers: mferencevic, pullbot
Differential Revision: https://phabricator.memgraph.io/D940
Summary:
- Removed durability::Summary because it was wired into reader and stopped me from recovering WAL files.
- Refactored and renamed BufferedFile(Reader/Writer) to HashedFile(Reader/Writer).
- Vertex and edge counts in the snapshot are now hashed.
Breaking snapshot compatibility again (hashing), but since the previous version was not released, and we are not caching snapshots, the previous version does not need to be supported.
Reviewers: teon.banek, mislav.bradac, buda
Reviewed By: teon.banek, mislav.bradac
Subscribers: dgleich, pullbot
Differential Revision: https://phabricator.memgraph.io/D932
Summary:
New snapshot structure:
- magic number
- snapshot version (old-version recovery not yet implemented)
- transaction snapshot (will be used in the WAL)
- the rest is as before (indices, vertices, edges)
Not backward compatible with the old snapshotting.
Does not improve error handling (user feedback). A task for that has been added.
Reviewers: buda, mislav.bradac, mferencevic, teon.banek
Reviewed By: teon.banek
Subscribers: teon.banek, dgleich, pullbot
Differential Revision: https://phabricator.memgraph.io/D912
Summary: This change increases the planning time, but should reduce memory consumption.
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D901
Summary: Added support for optional properties, random integers (uniform distr) and random strings.
Reviewers: mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D885
Summary:
This puts the whole installation and packaging under a single point of
entry. (Docker, DEB, RPM, etc.)
Rename alpha.dockerfile to beta.dockerfile
Use Debian Stretch for docker
Remove building old hardcoded compiler
Rename build_interpreter to build_memgraph
Remove unused config-file
Reviewers: mferencevic, buda
Reviewed By: mferencevic, buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D857
Summary:
- Removed BreadthFirstAtom, using EdgeAtom only with a Type enum.
- Both variable expansions (breadth and depth first) now have mandatory inner node and edge Identifiers.
- Both variable expansions use inline property filtering and support inline lambdas.
- BFS and variable expansion now have the same planning process.
- Planner modified in the following ways:
- Variable expansions support inline property filtering (two filters added to all_filters, one for inline, one for post-expand).
- Asserting against existing_edge since we don't support that anymore.
- Edge and node symbols bound after variable expansion to disallow post-expand filters to get inlined.
- Some things simplified due to different handling.
- BreadthFirstExpand logical operator merged into ExpandVariable. Two Cursor classes remain and are dynamically chosen from.
As part of planned planner refactor we should ensure that a filter is applied only once. The current implementation is very suboptimal for property filtering in variable expansions.
@buda: we will start refactoring this these days. This current planner logic is too dense and complex. It is becoming technical debt. Most of the time I spent working on this has been spent figuring the planning out, and I still needed Teon's help at times. Implementing the correct and optimal version of query execution (avoiding multiple potentially expensive filterings) was out of reach also due to tech debt.
Reviewers: buda, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot, buda
Differential Revision: https://phabricator.memgraph.io/D852
Summary:
Add json and cppitertools to libs/CMakeLists.txt.
Import external projects as libraries.
This removes the need to use `add_dependencies` in order to link with
external project.
Extract common ExternalProject_Add function.
Add macro for easier addition of external libraries.
Reviewers: mislav.bradac, mferencevic
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D845
Summary: - modified all utils/algorithm functions to be inline and in the utils namespace
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D830
Summary:
I started with cleaning flags up (removing unused ones, documenting undocumented ones). There were some flags to remove in `QueryEngine`. Seeing how we never use hardcoded queries (AFAIK last Mislav's testing also indicated they aren't faster then interpretation), when removing those unused flags the `QueryEngine` becomes obsolete. That means that a bunch of other stuff becomes obsolete, along with the hardcoded queries. So I removed it all (this has been discussed and approved on the daily).
Some flags that were previously undocumented in `docs/user_technical/installation` are now documented. The following flags are NOT documented and in my opinion should not be displayed when starting `./memgraph --help` (@mferencevic):
```
query_vertex_count_to_expand_existsing (from rule_based_planner.cpp)
query_max_plans (rule_based_planner.cpp)
```
If you think that another organization is needed w.r.t. flag visibility, comment.
@teon.banek: I had to remove some stuff from CMakeLists to make it buildable. Please review what I removed and clean up if necessary if/when this lands. If the needed changes are minor, you can also comment.
Reviewers: buda, mislav.bradac, teon.banek, mferencevic
Reviewed By: buda, mislav.bradac
Subscribers: pullbot, mferencevic, teon.banek
Differential Revision: https://phabricator.memgraph.io/D825
Summary: The constness of the DbAccessor interferes with caching the results.
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D771
Summary:
There was only two files in dbms directory so I moved them to database
directory.
Reviewers: buda
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D540
Summary:
- added functionality to `GraphDbAccessor` for cardinality estimates
- changed all `GraphDbAccessor::Count...` functions to return `int64_t`
- added the need functionality into `LabelPropertyIndex`
- modified `SkipList::position_and_count` to accept a custom `equals` function. Equality could not be implemented using only the custom `less` because it compares a templated `TItem` with skiplist element type `T`, and is therefore not symetrical.
Reviewers: teon.banek, buda, mislav.bradac
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D521
Summary:
- refactored so `less` is used instead of `greater`
- added a fuzzy unit test
Reviewers: mislav.bradac, buda, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D519
Summary: This is the first implementation that seems to work. I am not happy with it's complexity. Might attempt a simpler implementation, at the cost of some performance.
Reviewers: dgleich, buda
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D502
Summary:
CMake is smart enough to transitively detect dependencies and link them
appropriately. Therefore, it is enough that we put all libraries that
memgraph uses to the dependency list of memgraph_lib and memgraph_pic
targets.
Patch the fmt library for C++14 and higher
fmt library would detect that C++11 is supported and then put the
compiler flag. This flag was set so it overrides parent project compiler
flags. This override from fmt would prevent us from using C++14
features. New version (3.1) of fmt resolves this issue, but it hasn't
been released yet. Therefore, this commit updates the script which
clones fmt to use the released 3.0.1 version and apply the fix on that.
Reviewers: dgleich, buda
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D441
