Summary:
Previously, our implementation of the Bolt protocol buffered all results in
memory before sending them out to the client. This implementation immediately
streams the results to the client to avoid any memory allocations. Also, this
implementation splits the interpretation and pulling logic into two.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1495
Summary:
Session specifics have been move out of the Bolt `executing` state, and
are accessed via pure virtual Session type. Our server is templated on
the session and we are setting the concrete type, so there should be no
virtual call overhead. Abstract Session is used to indicate the
interface, this could have also been templated, but the explicit
interface definition makes it clearer.
Specific session implementation for running Memgraph is now implemented
in memgraph_bolt, which instantiates the concrete session type. This may
not be 100% appropriate place, but Memgraph specific session isn't
needed anywhere else.
Bolt/communication tests now use a dummy session and depend only on
communication, which significantly improves test run times.
All these changes make the communication a library which doesn't depend
on storage nor the database. Only shared connection points, which aren't
part of the base communication library are:
* glue/conversion -- which converts between storage and bolt types, and
* communication/result_stream_faker -- templated, but used in tests and query/repl
Depends on D1453
Reviewers: mferencevic, buda, mtomic, msantl
Reviewed By: mferencevic, mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1456
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:
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:
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:
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:
If there was no plan caching, the CachedPlan would not survive
`Interpreter::operator()`, as it was not owned by the
`Interpreter::Result`. If there was caching, it could hapen that the
cache got invalidated while that plan was being interpreted (by
another thread) without that interpretation retaining ownership.
Also simplified code around this.
Reviewers: mislav.bradac, teon.banek
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1084
Summary:
AST caching should be well tested by now.
We should consider removing `Context.is_query_cached_` member as well as the
implementation and tests for `CypherMainVisitor`.
Reviewers: mislav.bradac, mferencevic, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D833
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:
This fixes a bug, where streaming would try to get the name of the symbol from
an invalid token position. For example, `MATCH (n) WITH n RETURN *`
Reviewers: florijan, mislav.bradac
Reviewed By: florijan, mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D811
Summary:
This is done when the generated AST will be cached.
Remove LiteralsPlugger.
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D788
Summary:
Benchmark planning and estimating indexed ScanAll. According to the benchmark,
caching speeds up the whole process of planning and estimation by a factor of
2. Most of the performance gain is in the `CostEstimator` itself, due to plenty
of calls to `VerticesCount` when estimating all of the generated plans.
Reviewers: mislav.bradac, florijan
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D765
Summary:
Moved Neo4j config to config dir.
Neo4j and PostgreSQL are now downloaded to libs.
Renamed metadata flags in memgraph.
Changed apollo generate for new harness.
Reviewers: mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D741
Summary:
This allows for inserting dummy DbAccessor in tests. Unfortunate side
effect of this change is that the whole implementation had to be moved
from cpp to hpp.
Also templatize remaining RuleBasedPlanner implementation
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D704
Summary:
This is a simple integration of multiple plan generation and cost
estimation. Each plan produced by VariableStartPlanner is cost estimated
and the best is used for execution.
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D424
Summary:
This change modifies the planning API to be more general, in order to support
picking different planning strategies. The current planning strategy has been
named RuleBasedPlanner.
Reviewers: florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D411
Summary:
Make Symbol members read only.
Check WITH/RETURN * in SymbolGenerator.
Test semantic checks for WITH/RETURN *.
Sort expanded user identifiers by name.
Test planning WITH/RETURN *.
Reviewers: buda, florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D357
