Summary:
Utils source files are now moved to a standalone mg-utils library.
Unit and manual tests are no longer collected using glob recursion in
cmake, but are explicitly listed. This allows us to set only required
dependencies of those tests.
Both of these changes should improve compilation and link times, as well
as lower the disk usage.
Additional improvement would be to cleanup utils header files to be
split in .hpp and .cpp as well as merging threading into utils. Other
potential library extractions that shouldn't be difficult are:
* data_structures
* io/network
* communication
Reviewers: buda, mferencevic, dgleich, ipaljak, mculinovic, mtomic, msantl
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1408
Summary:
Command id is necessary in remote produce to identify an ongoing pull
because a transaction can have multiple commands that all belong under
the same plan and tx id.
Reviewers: teon.banek, mtomic, buda
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1386
Summary:
Removing `AS_IS` from GraphView because it doesn't seem like it is necessary for query execution and it also has weird semantics (you might get a mix of old and new records). `Unwind`, `OrderBy` and `PullRemoteOrderBy` now use `OLD` graph view.
Remove AS_IS from GraphView
Fix query_cost_estimator tests
Fix query_expression_evaluator tests
Fix query_plan_match_filter_return tests
Fix query_plan_create_set_remove_delete tests
Fix query_plan_accumulate_aggregate tests
Reviewers: teon.banek, buda
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1390
Summary:
A simplified end-to-end implementation
POD interface set-up, still have bugs with HDDkeys
Version bug fix and first iterator implementation
Fixed out-of-scope reference in PVS iterator
Added PVS unit tests
Reviewers: buda, mferencevic, dgleich, teon.banek
Reviewed By: buda, dgleich
Subscribers: mferencevic, pullbot
Differential Revision: https://phabricator.memgraph.io/D1369
Summary: Global address of `from` was stored in Edge record when created via CreateEdge RPC.
Reviewers: buda, msantl, dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1387
Summary:
Pointers in AstTreeStorage can point to same nodes. These nodes
should be serialized(saved) only once when serializing Ast tree.
Same goes for deserializing(loading).
When deserializing nodes, one should not use storage Create method,
because it will add node which isn't completely loaded to storage vector.
Therefore, one should use new Deserialize method which doesn't
add node to storage vector. Inserting node into storage vector
is defered until all node data is loaded.
Pass pointer to saved uids set, instead of storage
Delete unused set
Reviewers: teon.banek, msantl
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1344
Summary:
Added a new markdown file for concepts and a new test to test the edge
case with upper bound.
Reviewers: teon.banek, mtomic, dgleich, buda, ipaljak
Reviewed By: teon.banek, dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1366
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:
- Removed a lot of stuff that was incorrect and/or unnecessary
- Fixed const-correctness in the skiplist family
Reviewers: dgleich, teon.banek, buda
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1351
Summary:
Implemented cluster discovery in distributed memgraph.
When a worker registers, it sends a RPC request to master.
The master assigns that worker an id and sends the information about other
workers (pairs of <worker_id, endpoint>) to the new worker.
Master also sends the information about the new worker to all existing workers
in the process of worker registration.
After the last worker registers, all memgraph instances in the clusters should
know about every other.
Reviewers: mtomic, buda, florijan
Reviewed By: mtomic
Subscribers: teon.banek, dgleich, pullbot
Differential Revision: https://phabricator.memgraph.io/D1339
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: Adds a commit log garbage collector, which clears old transactions from the commit log
Reviewers: florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1310
Summary:
When commiting/aborting a transaction in tx master engine, make a two
phase commit to all workers so they can stop all futures and clear
transactional cache.
Reviewers: dgleich, florijan
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1320
Summary:
The network layer now has a `Session` that handles all things that should be
done before the `Execute` method is called on sessions. Also, all sessions
now communicate using streams instead of holding the input buffer and writing
to the `Socket`. This design will allow implementation of a SSL middleware.
Reviewers: buda, dgleich
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1314
Summary:
Remove "produce_" and "Produce" as prefix from all distributed stuff.
It's not removed in src/query/ stuff (operators).
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1315
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:
Writers preference is not guaranteed by the standard and as such
there are variations between implementations in different versions
of libphthread.
Reviewers: dgleich
Reviewed By: dgleich
Differential Revision: https://phabricator.memgraph.io/D1305
Summary:
Ensures that query plans are invalidated on the remote only when it's
guaranteed they will never be used on the master. This is done by
invalidating remote caches in the `CachedPlan` destructor.
There are two unplesant side-effects. First, an RPC call is made in an
object destructor. This is somewhat ugly, but not that different then
making an RPC call that must succeed in any other function. Note that
this does NOT slow down any query execution because the relevant
destructor is called by the skiplist garbage collector. The second ugly
side-effect is that in the unit test now we need to sleep to ensure the
skiplist GC destructs a cached plan before checking that it's
invalidated on the remote worker.
We might want to redesign this at some point.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1302
Summary:
- Remove caches on workers as a result of plan expiration or race
during insertion.
- Extract caching functionality into a class.
- Minor refactor of Interpreter::operator()
- New RPC and test for it.
- Rename ConsumePlanRes to DispatchPlanRes for consistency, remove
return value as it's always true and never used.
- Interpreter is now constructed with a `GraphDb` reference. At the
moment only for reaching the `distributed::PlanDispatcher`, but in
the future we should probably use that primarily for planning.
I added a function to `PlanConsumer` that is only used for testing.
I prefer not doing this, but I felt this needed testing. I can remove
it now if you like.
Reviewers: teon.banek, msantl
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1292
Summary:
Instead of waiting for a fix period for the coordinations to start and
coordinate with the master, wait for each of them individually to report
being done.
Also: rename `WorkerInThread` to `WorkerCoordinationInThread`.
Reviewers: dgleich, teon.banek, msantl
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1288
Summary:
This fixes a bug where the planning would raise NotYetImplemented error,
due to preventing plan splitting while the operator is already on
master. For example, `MATCH (a), (b) CREATE (a)-[e:r]->(b) RETURN e`
would split the plan after Cartesian and before Create. Thus, the rest
of the plan would be on master, including the Accumulate before Produce.
We still can (and must) replace Accumulate with Synchronize but this
would fail due to unneeded check.
Reviewers: florijan, msantl
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1272
Summary:
I have not thoroughly thought this through, especially the worker
destruction (is it legit to abort all running tx?), but it's tested to
abort during remote pull, what we need.
Also I improved error handling for vertex deletion failure during
remote pull (@dgleich).
Reviewers: teon.banek, msantl, dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1263
Summary:
Instead of passing `coordination`, pass `rpc_worker_clients` that
holds a map of worker_id->clientPool. By having only one instance of
`RpcWorkerClients` that is owned by `GraphDB` and passing it by refference
we'll share the same client pools for rpc clients.
Reviewers: teon.banek, florijan, dgleich, mferencevic
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1261
Summary:
Release of per-transaction data in distributed Memgraph refactored. The
master node no longer releases each time a transaction is done, thus
offloading some work from the engine.
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1235
Summary:
Remove a method in tx::Engine whose results can be obtained from commit
log info (also guaranteed to be globally correct in distributed).
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1240
Summary:
Difficult to test properly as the problem was an implicit conversion of
`gid::Gid` to `mvcc::VersionList<> *`. The only proper way to defend
against this would be to make `gid::Gid` a type.
The `CHECK` added in this diff does not help, but should be there, so...
Reviewers: dgleich
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1244
Summary:
During distributed execution, OrderBy is split across workers and the
master gets to merge those results via PullRemoteOrderBy. Since this
operator may be an input to almost any other operator, virtual accessors
to `input` have been added in LogicalOperator.
Depends on D1221
Reviewers: florijan, msantl, buda
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1232
Summary:
Extracted `TypedValueVectorCompare` and `RemotePuller` from operators
so it can be reused.
The new `PullRemoteOrerBy` operator pulls one result from each worker and one
from master, relies on the fact that workers/master returned sorted results,
returns the next one in order, and pulls the source of that result to get the
next one.
Depends on D1215 that (at the moment) is still in review.
Reviewers: florijan, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1221
Summary:
- The expansion vertex gets created on the origin's worker
- The edge automatically gets created wherever necessary
- Vertex creation logic reuse
- End to end test
Reviewers: teon.banek, msantl
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1227
Summary:
To see the thread names in htop press <F2> to enter setup and under
'Display options' choose 'Show custom thread names'.
Reviewers: buda, teon.banek, florijan
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1234
Summary:
- Add the said test
- Add `workerid` function
- Add random wait (enabled with flag) to `rpc::Client::Call` for network
latency simulation
Reviewers: buda, mferencevic, teon.banek
Reviewed By: buda, teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1222
Summary:
Previously, the RPC stack used the network stack only to receive messages. The
messages were then added to a separate queue that was processed by different
thread pools. This design was inefficient because there was a lock when
inserting and getting messages from the common queue.
This diff removes the need for separate thread pools by utilising the new
network stack design. This is possible because the new network stack allows
full processing of the network request without blocking the whole queue.
Reviewers: buda, florijan, teon.banek, dgleich, mislav.bradac
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1229
Summary:
This may improve the query execution workload, because the Expand will
yield local results while it waits for remote ones. Note that we rely on
the fact that walking the graph produces results without any predetermined
order. Therefore, we can yield paths as we see fit. Enforcing the order
is done through OrderBy operator, and this change shouldn't affect that.
Reviewers: florijan, msantl, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1215
Summary:
Updating a record locally while there is an remote update waiting to be applied caused
the operation to return as already deleted, instead of applying it
Reviewers: florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1226
Summary:
Previously, the network stack `communication::Server` accepted connections and
assigned them statically in a round-robin fashion to `communication::Worker`.
That meant that if two compute intensive connections were assigned to the same
worker they would block each other while the other workers would do nothing.
This implementation replaces `communication::Worker` with
`communication::Listener` which holds all accepted connections in one pool and
ensures that all workers execute all connections.
Reviewers: buda, florijan, teon.banek
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1220
Summary:
- Add `database::GraphDb::GetWorkerIds()`
- Change `CreateNode` constructor API
- Make `CreateNode` distribute nodes uniformly over workers
Did not yet modify `CreateExpand`, coming in the next diff.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1216
Summary:
Implementation of remote vertex and edge creation. This diff addresses
the creation API (`GraphDbAccessor::InsertEdge`,
`GraphDbAccessor::InsertRemoteVertex`) and the necessary RPC and
`RemoteCache` stuff.
What is missing for full remote creation support are
`query::plan::operator` changes that are expected to minor. Pushing this
diff as it's large enough, operator and end to end tests in the next.
Also, the naming of existing structures and files is confusing (update
refering to both updates and created, `results` used too often etc.). I
will address this too, but feel free to comment on bad naming.
Reviewers: dgleich, teon.banek, msantl
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1210
Summary:
This is still very much in progress. No advanced checks are done to
prevent planning unimplemented things. Basic Cartesian product should
work, for example `MATCH (a), (b) CREATE (a)-[:r]->(c)-[:r]->(b)`. But
anything more advanced may lead to undefined behaviour of the planner
and therefore execution. Use at your own risk!
Add ModifiedSymbols method to LogicalOperator
For planning Cartesian, we need information on which symbols are filled
by operator sub-trees. Currently, this is used to set symbols which
should be transferred over network. Later, they should be used to detect
whether filter expressions use symbols modified from Cartesian branches.
Then we will be able to ensure correct dependency of filters and their
behaviour.
Prepare DistributedPlan for multiple worker plans
Since Cartesian branches need to be split and handled by each worker, we
now dispatch multiple plans to workers.
Reviewers: florijan, msantl, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1208
Summary:
Rename and fix concurrent list test.,
This tests a fix for the concurrent list.I was not able to reproduce the flakyness, but this could be it.
If it happens again we'll know that this is not the solution to the problem, and look further.
Change memory ordering
Reviewers: mferencevic
Reviewed By: mferencevic
Subscribers: buda, pullbot
Differential Revision: https://phabricator.memgraph.io/D1188
Summary:
On the master cleanups are hooked directly into the transaction engine.
This is beneficial because the master might have bigger caches and we
want to clear them as soon as possible.
On the workers there is a periodic RPC call to the master about living
transactions, which takes care of releasing local caches. This is
suboptimal because long transactions will prevent cache GC (like with
data GC). It is however fairly simple.
Note that all cleanup is not done automatically and `RemotePull` has
been reduced accordingly. @msantl, please verify correctness and
consider if the code can be additionally simplified.
Reviewers: teon.banek, msantl
Reviewed By: msantl
Subscribers: pullbot, msantl
Differential Revision: https://phabricator.memgraph.io/D1202
Summary:
Pulls left op cursor and keeps the result, and then for each pull of
the right op cursor, adds all the left op results to produce a cartesian
product.
Reviewers: teon.banek, florijan
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1201
Summary:
Get rid of client class
Fix cppcheck errors
Add documentation to metrics.hpp
Add documentation to stats.hpp
Remove stats from global namespace
Fix build failures
Refactor a bit
Refactor stopwatch into a function
Add rpc execution time stats
Fix segmentation fault
Reviewers: mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1200
Summary:
We have been using `Edges::VertexAddress` and `Edges::EdgeAddress` a lot
in other parts of the codebase because it's cleaner to write then
`Address<mvcc::VersionList<Edge>>`, especially in code what should not
really be MVCC-aware. However, a lot of that code should not really be
`Edges` aware either, as that's a storage datastructure that should not
be exposed.
This became annoying, so I extracted these addresses into a type-file. I
don't really like this approach, it might be better to have
`Vertex::Address` and `Edge::Address`, but that means we'd have to
import those headers and we'd get circular dependencies.
“The horror! The horror!”
- Joseph Conrad, Heart of Darkness
Reviewers: teon.banek, buda
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1204
Summary:
Updates are supported, insertions and removals not in this diff. The
test is a bit overdesigned, it happens.
Reviewers: teon.banek, dgleich, msantl
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1176
Summary:
Defined a new test based on reported bug, for multiple remote expansion.
Fixed the bug. Introduced minor refactors in distributed unit testing.
Reviewers: mculinovic, dgleich
Reviewed By: mculinovic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1173
Summary:
This is a basic take on planning distributed writes. Main logic is in handling
the Accumulate operator, which requires Synchronize operation if the results
are used after modification.
Tests for planning distributed writes have been added.
Reviewers: florijan, msantl
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1172
Summary:
This diff consolidates local and remote update handling. It ensures and
tests that updates for remote elements are visible locally (on the
updating worker).
The next part will be accumulating remote updates and applying them on
the owner.
Also extracted a common testing fixture.
Reviewers: dgleich, buda, mtomic
Reviewed By: mtomic
Subscribers: mtomic, pullbot
Differential Revision: https://phabricator.memgraph.io/D1169
