Summary:
GraphDbAccessor is now constructed only through GraphDb. This allows the
concrete GraphDb to instantiate a concrete GraphDbAccessor. This allows
us to use virtual calls, so that the implementation may be kept
separate. The major downside of doing things this way is heap allocation
of GraphDbAccessor. In case it turns out to be a real performance
issues, another solution with pointer to static implementation may be
used.
InsertVertexIntoRemote is now a non-member function, which reduces
coupling. It made no sense for it to be member function because it used
only the public parts of GraphDbAccessor.
Reviewers: msantl, mtomic, mferencevic
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1504
Summary:
This is the first step in cutting the crazy dependencies of
communication module to the whole database. Includes have been
reorganized and conversion between DecodedValue and other Memgraph types
(TypedValue and PropertyValue) has been extracted to a higher level
component called `communication/conversion`. Encoder, like Decoder, now
relies only on DecodedValue. Hopefully the conversion operations will
not significantly slow down streaming Bolt data.
Additionally, Bolt ID is now wrapped in a class. Our storage model uses
*unsigned* int64, while Bolt expects *signed* int64. The implicit
conversions may lead to encode/decode errors, so the wrapper should
enforce some type safety to prevent such errors.
Reviewers: mferencevic, buda, msantl, mtomic
Reviewed By: mferencevic, mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1453
Summary:
Wal retention test was flaky, this kinda fixes it.
It's hard to fix it completely since there are separate threads happening which
are not synchronized, and forcing the synchronization from the outside would
not agree to the specifications i.e. single-threadness of WAL.
Reviewers: buda
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1358
Summary: Make synchronized snapshot. This invokese the snapshooter on workers on the master snapshot scheduler interval.
Reviewers: msantl, mtomic
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1334
Summary:
When performing recovery, ensure that the transaction ID in engine is
bumped to one after the max tx id seen in recovery.
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1312
Summary:
Find[Vertex|Edge] -> Find[Vertex|Edge]Optional
Find[Vertex|Edge]Checked -> Find[Vertex|Edge]
In some places change old code that finds-optional and immediately checks
to use the checked functionality.
It seems that in all the src/ stuff optional finds are no loger used,
only in tests, but there they are used extensively so I don't feel those
functions should be removed.
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1309
Summary:
Refactor in two ways. First, expose members without getters as we will
need most of them in distributed. And this was always the sensible thing
to do. Second, add storage type values to deltas. This is also a
sensible thing to do, and it will be very beneficial in distributed. We
didn't do it before because name<->value type mappings aren't guaranteed
to be the same after recovery. A task has been added to address this
(preserve mappings in durability).
Reviewers: dgleich, buda
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1167
Summary:
Adds worker id to snapshot and wal filename.
Adds a new worker_id flag to be used for recovering a worker with a distributed snapshot.
Adds worker_id field to snapshot to check for consistency.
Reviewers: florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1096
Summary:
GraphDb is refactored to become an API exposing different parts
necessary for the database to function. These different parts can have
different implementations in SingleNode or distributed Master/Server
GraphDb implementations.
Interally GraphDb is implemented using two class heirarchies. One
contains all the members and correct wiring for each situation. The
other takes care of initialization and shutdown. This architecture is
practical because it can guarantee that the initialization of the
object structure is complete, before initializing state.
Reviewers: buda, mislav.bradac, dgleich, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1093
Summary: Operations are moved and renamed from WAL to a separate file in preparation for HA and distributed storage.
Reviewers: florijan, mtomic, mislav.bradac
Reviewed By: florijan
Subscribers: mislav.bradac, pullbot
Differential Revision: https://phabricator.memgraph.io/D1034
Summary:
It occurred that part of the durability flakyness test might be that the
same durability directory is used always. If the test is run
simultaneously on a single system, there will be interference.
This might not actually fix all the flakyness :(
I also made the `utils::RandomString` function since that's now used in
multiple places, tested it etc.
Reviewers: buda, dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1020
Summary: Once a snapshot is successfully written, delete WAL files which are no longer necessary for recovery. Note that this prohibits recovering the WAL from any except the last snapshot.
Reviewers: buda, mislav.bradac, dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1000
Summary:
In preparation for distributed storage we need to have labels/properties/edgetypes uniquely identifiable by their ids, which will be global in near future.
The old design has to be abandoned because it's not possible to keep track of global labels/properties/edgetypes while they are local pointers.
Reviewers: mislav.bradac, florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D993
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
