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:
Added a warning to the log. Every 3 seconds (let's not make that configurable). Can be turned off.
I still don't like this. We are raising another thread and reading a file to do monitoring. We're developing a DB, not a sys monitor. Serious admins do that themselves. But, here it is.
UPDATE:
Cleaned up `utils/sysinfo/memory`. Removed all unused functions. Removed the faulty memory check in `tests/concurrent`.
Reviewers: buda, mferencevic, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D819
Summary:
Setup scaffolding for building Memgraph tools.
Change `utils::Split` without delimiter to split on whitespace.
This should make `Split` behave just like Python's `str.split`, which is
more practical for splitting on word boundaries.
Add `utils::StartsWith` function.
Rewrite csv_to_snapshot to C++.
Reviewers: mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D822
Summary:
Added path encoding and decoding in our Bolt layer. Returning paths to the Neo client seems to work fine.
Not sure how to test that the decoded works fine (our client?).
Tests are not written, that suite is complicated. Leaving that to mferencevic.
Also reduced DecodedValue a bit with macros. Less code, less error prone.
Reviewers: buda, florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D810
Summary:
Test planner splits MATCH ... WHERE
Remove distinction between FilterAnd and AndOperator
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D814
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: Removed the traversal API, been waiting for named path to land because that data structure has replaced traversal's Path. I left the wiki page of the API, just put a warning that it's not used.
Reviewers: buda, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D809
Summary:
Three TODOs resolved.
1. around line 897 - we currently don't support expansion into existing variable length edges (there is a TODO in symbol_generator.cpp:213), so this should not be done at the moment.
2. around line 1025 - This TODO was on review and nobody commented, so I'm removing it. Should have done that when the diff landed.
3. around line 1560 - This does not seem possible. Edge-uniqueness checks happen within a single `[OPTIONAL ] MATCH`. If it is OPTIONAL (the case interesting here), then the uniqueness check also gets planned under the optional branch. So, if an optional fails, the uniqueness check will get skipped, as opposed to getting executed over a Null. I added an edge-case test to verify this (and checked with the planner test).
Reviewers: buda, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D807
Summary:
- Keys() functions in the indices can't be const because ConcurrentMap doesn't provide const accessors (and they are broken in skiplist) :D
- no cucumber tests because many tests create indices so it's hard to say what's inside and what not
Reviewers: buda, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D797
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:
Replaced std::list with std::vector in all plan operators. Performance increase in harness tests is not visible. Defined a custom test:
```
unwind range(0, 1000000) as x
create ({a: tointeger(rand() * 100), b: tointeger(rand() * 100), c: tointeger(rand() * 100), d: tointeger(rand() * 10), e: tointeger(rand() * 10), f: tointeger(rand() * 10)});
match (n) return min(n.a), max(n.b), sum(n.c), n.d, n.e, n.f
match (n) with distinct n.a AS a, n.b AS b, n.c AS c, n.d AS d, n.e AS e, n.f AS f return count(*)
```
In that test performance gains are 9.8% on the aggregation query (mean 0.83s vs 092s) and 34% (mean 2.15s vs 3.25s) on the distinct query. Doubt we'll see much on any of the LDBC tests because they don't stress those operators nearly as much.
Reviewers: buda, teon.banek, mislav.bradac
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D778
Summary:
Antlr grammar has been updated to support putting edge types after the BFS
symbol. Planner collects edge type filters for BFS and inlines them in the
operator by joining the filter with the user input BFS filter itself. This
requires no change from the standpoint of the operator. On the other hand, in
order to use the faster lookup by a single edge type, `ExpandBreadthFirst`
operator now accept an optional edge type. The edge type is passed from the
planner only if the user is filtering by a single type.
Unit tests as well as tck have been updated.
Reviewers: florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D777
Summary: Reduces latency on LDBC query 9 from 7.9sec to 6.8sec (14%). That query has 650k rows in ORDER BY, 3 ordering elements and 10ish values get returned (both of them are now accumulated into vectors).
Reviewers: buda, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D775
Summary:
Add function First to utils.
Insert EdgeType into Expand during planning.
Reviewers: florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D769
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:
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:
- The `Edges` data structure now handles common ops, including providing an iterator over edges whose "other" vertex is know.
- This should improve performance on dense_expand tests in the harness without other side-effects.
- query::plan::Expand operator modified not to check for existing-node stuff since that now gets handled by the `Edges` data structure.
- `Edges::Iterator` implemented only for const iterators since that suffices for now. Can implement non-const if the need arrises.
Reviewers: buda, mislav.bradac, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D763
Summary:
Measured improvements in a test scenario with 4 labels, 1M vertices for each label:
Old code: ~2.5 seconds per index
New code: ~1.5 seconds per index
When building an index for a non-existing label the updated code is done immediately. The old code depends on the number of vertices in the database.
The new code *could* be slower when building an index for a label that has a lot of vertices, and the index is not garbage collected recently and contains a lot of junk. This can be avoided by a simple check in the `BuildIndex` function (if label_index cardinality > total cardinality), if you like.
Reviewers: buda, mislav.bradac, teon.banek
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D767
Summary: `assert` function added. Useful to us for asserting DB state in harness tests. Potentially useful to the client for breaking out of a query as soon as a predicate fails, as opposed to collecting result and checking them client-side.
Reviewers: buda, mislav.bradac, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D750
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: Some TypedValue arithmetic ops threw exceptions for the wrong reasons, the op applicability type checks were wrong. Also the tests for that behavior were wrong. These are the fixes.
Reviewers: mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D724
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:
Added:
- map support in PropertyValue
- conversion of map TypedValue to PropertyValue if appropriate flag is set (undocumented because it's private)
- ordering of map PropertyValue in LabelPropertyIndex
- issue raised regarding list and value property modifications in storage (currently unsupported)
Maybe I missed some feature or whatever?
Reviewers: mislav.bradac, buda, teon.banek
Reviewed By: mislav.bradac, buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D692
Summary:
This change should allow for passing a different PlanningContext and/or
GraphDbAccessor. In turn, we can write tests which pass a dummy context
for decoupled testing of the planning process (from the rest of the
system).
Reviewers: mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D700
Summary:
It's purpose is to illustrate that currently expansion from a single node (with a fixed degree) does not execute in consistent time, but the execution time depends on the rest of the graph (that's disconnected). Current benchmark results:
```
florijan@florxps:~/Memgraph/memgraph/build$ ./tests/benchmark/expansion
Run on (8 X 3500 MHz CPU s)
2017-08-17 16:06:30
***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead.
***WARNING*** Library was built as DEBUG. Timings may be affected.
Benchmark Time CPU Iterations
-------------------------------------------------------------------------
ExpansionBenchFixture/Match/1 0 ms 0 ms 4903
ExpansionBenchFixture/Match/1024 0 ms 0 ms 4785
ExpansionBenchFixture/Match/1024k 0 ms 0 ms 4623
ExpansionBenchFixture/Expand/1 9 ms 9 ms 83
ExpansionBenchFixture/Expand/1024 20 ms 20 ms 41
ExpansionBenchFixture/Expand/1024k 3430 ms 3430 ms 1
```
Reviewers: mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D676
Summary:
This is needed in cases when the planner decides to start expanding from
the other end.
Reviewers: mislav.bradac, florijan
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D681
Summary: Because it was unnecessary and also implemented wrong (if someone tried using a Schduler with something other then std::mutex, it would not compile). We can trivially add this if it ever becomes necessary.
Reviewers: buda, mislav.bradac
Reviewed By: buda, mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D666
Summary:
A single line (graph_db.cpp:109 in the new code) was missing. This should have been done in D355 (made by DGleich, approved by Flor AND Buda AND Mislav :D).
Converted a lambda to a method for convenience.
Reviewers: buda, dgleich, mislav.bradac
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D665
Summary:
Matching variants are generated iteratively and limited. Additionally,
When generating expansions, if there is nothing to continue on the
expanded nodes, simply append all the remaining expansions to the
currently generated one. This should speed up queries with large number
of `MATCH` clauses.
Reviewers: mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D612
Summary: Changed on-scope-exit-mechanism from macro (with two auto-generated variables and an all-capturing lambda) to an explicitly created variable that takes an std::function argument.
Reviewers: buda, mislav.bradac, teon.banek
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D659
Summary: Not strictly neccessary, but it's been itching me. It took an hour.
Reviewers: buda, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D648
Summary:
- added only one function for getting the total (in + out) vertex degree, it's required for the Ravelin use-case
- specific `degree_in` and `degree_out` functions can be added as necessary
- also fixed random_graph_generator bug (needed it for testing)
Reviewers: buda, mislav.bradac
Reviewed By: buda, mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D652
Summary:
Now all ScanAll and Expand ops are covered by the cost estimator. For ScanAll with indices cost estimation is pretty good, for new Expand ops it is tragically bad (Expand to the power of expansion depth, plus arbitrary filtering). Static cost estimation is wrong wrong wrong.
Currently cost estimation of even trivial plans that use indices is wrong because the planner leaves filtering expressions that are implicitly handled by the index in the operator tree, IIRC. Tasking Teon to revise this, even though I'm not sure how bad an influence this has on cost estimation and it's use in plan choosing.
Reviewers: mislav.bradac, teon.banek, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D633
Summary:
This diff contains a bug fix for the expansion operators that are currently on dev.
More importantly, it proposes end-to-end testing for edge-cases for which it's a
pain to write single-phase tests. In my opinion this is OK, you're all reviewers so
you can comment.
The test relies on left-to-right query execution. We need this guarantee in tests
like this. I propose renaming "RuleBasedPlanner" to "LeftToRightPlanner" to make
this explicit. As Teon is not here at the moment, will make this a task/discussion.
Reviewers: buda, mislav.bradac, teon.banek, lion
Reviewed By: mislav.bradac
Subscribers: mferencevic, pullbot
Differential Revision: https://phabricator.memgraph.io/D626
Summary:
Not complete (but review can start):
- implementation should be done
- still need to finish tests
- documentation missing
Reviewers: mislav.bradac, teon.banek, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D616
Summary: Fixed bug for SkipList::position_and_count for an item lesser then all skiplist elements.
Reviewers: mislav.bradac
Reviewed By: mislav.bradac
Differential Revision: https://phabricator.memgraph.io/D629
Summary:
Implement trie and use it in stripper
Make it nicer
Reviewers: buda, florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D614
Summary:
`UNWIND` can come before `MATCH`, so it needs to break query parts. If
it didn't, a query part would incorrectly grab all the matches and plan
them incorrectly. A test for such a case has been added.
Reviewers: florijan
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D598
Summary:
Add All expression to Ast
Evaluate All expression
Visit All and generate symbols
Handle All when collecting context during planning
Reviewers: florijan, mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D587
Summary:
Add EdgeList symbol type and check for redeclaration
The result of variable path is a list of edges, so the symbol type has
been added. In the future, we need to extend the type checker and the
type structure to have a generic list type.
We also currently do not support reusing an already bound symbol for a
variable path, so the SymbolGenerator will raise a redeclaration error.
Reviewers: florijan, mislav.bradac
Reviewed By: mislav.bradac
Subscribers: pullbot, lion
Differential Revision: https://phabricator.memgraph.io/D574
Summary: A helper function added for transferring graph elements into some GraphDbAccessor.
Reviewers: mislav.bradac, buda, teon.banek
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D581
Summary:
Variable expansion logical operator added. Some functionalities are missing:
- taking into account optional matching when expanding into existing symbol
- accepting Expression bounds (current implementation takes size_t)
Also, a TODO is added for handling optional matching in the uniqueness operator (with an Asana task)
All this will be done in the following diff, this is already substantial.
Also, please consider if we want to have all those `VLOG`s in the code. Not very pretty. And I think that `VLOG` is not compiled-away in release build, will put an asana task.
Reviewers: teon.banek, mislav.bradac, buda
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D569
Summary:
Allow expressions for variable length path bounds
Replace test which expected a syntax exception
Since we now allow variable length to have an arbitrary expression, the
test case is obsolete. It was replaced with something that excepts an
expression which wasn't allowed before.
Reviewers: florijan, mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: lion, pullbot
Differential Revision: https://phabricator.memgraph.io/D568
Summary:
- GraphDbAccessor - index range API added
- index api tests refactored
- skiplist minor cleanup.
Reviewers: teon.banek, buda, mislav.bradac
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D533
Summary:
Add optional bounds to PropertyFilter and collect them
Relation operators (e.g. `<`, `>` ...) should be used to produce
scanning the index by a range of values. For that reason, PropertyFilter
is extended to store either the equality expression or range bounds.
The `AnalyzeFilter` function is extended to look for those operators and
see if their top level expression contains a property lookup. If it
does, a filter with a bound is generated.
Test for property comparison preventing index use
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D529
Summary:
This change allows for lazy calculation of Cartesian product, by using
an iterator. Using lazy evaluation, we can easily limit the number of
generated products and therefore the number of generated query plans.
Reviewers: florijan, mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D554
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:
Add Filters class for storing additional info
Add FindOr to utils/algorithm.hpp
Use all collected labels when scanning by them
Collect label filters inside WHERE
Document the Filters class
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan
Subscribers: pullbot, lion
Differential Revision: https://phabricator.memgraph.io/D515
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:
The new Bound class does not have comparison operators defined. The
reason being, we want to support having values which we may not want to
compare. For example, having an Expression which should first be
evaluated and then compared.
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D520
Summary:
Add ScanAllByLabelPropertyRange operator
This operator uses the label + property indexing feature to iterate over
the vertices. The property value of each vertex is checked whether it is
inside the given range of values. The range is inclusive from both
sides. If the value isn't in range, the vertex is filtered out.
This manual filtering should be replaced by a database API when it
becomes available.
Add ScanAllByLabelPropertyValue operator
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan, mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D503
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:
PushQueue with concurrent lock-free pushing, and single-threaded deletion. Iteration without modification can also be concurrent. Deletion should NOT be concurrent with iteration and other deletions, but can be concurrent with pushing.
There is no const iteraton at the moment, we can add it when necessary. Also I've not handled std::iterator_traits, might be fun getting into that :D
Reviewers: buda, dgleich, mislav.bradac
Reviewed By: dgleich
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D420
Summary: There was a big performance hit induced when removing consecutive nodes from the concurrent list. The reason why it was happening is that the iterator has a pointer to previous node, and uses that pointer to re-link the whole list after the deletion. That node wasn't alive because it was deleted earlier and was always being updated to the next deleted entry in the list while incrementing the iterator. This behaviour caused find_and_disconnect method to be invoked, which has an O(n) complexity. That made our removal of O(n) entries from the list run in O(n^2) time, which is obviously slow.
Reviewers: buda, mislav.bradac, florijan
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D483
Summary:
benchmark/query/stripped.cpp outputs garbage because of some race
condition in logger. Sometime even crashes, just be sure this
should be removed.
Reviewers: buda
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D477
Summary:
There were a couple of issues with handling the above 2 signals.
1) Calling `std::exit` from a signal handler is undefined behaviour.
The only defined way for a signal handler to stop the program is calling
one of: `std::_Exit`, `std::abort` or `std::quick_exit`. Neither of them
will completely clean the resources, so a clean exit is not possible.
Since SIGSEGV and SIGABRT happen in extraordinary circumstances that we
wish to debug 99% of the time, it makes sense to generate a core dump
which can be inspected by a debugger. Of the 3 termination functions,
only `std::abort` will generate a core dump, so it makes sense to use
that to stop the program.
Also, since we are now aborting as is the default behaviour on SIGSEGV
and SIGABRT, it becomes questionable why have a custom handler at all.
2) Raising an exception inside a signal handler is undefined behaviour
Although the handler by itself does not raise an exception, it is
possible for the logging facility to raise one. This is a real case when
logging a stack trace in particular. Stack trace is generated by
creating a string "<function name> <line location>". It is possible that
a function name will contain '{}' somewhere inside. This is usually the
case with anonymous functions. The generated string is then passed to
logging, which uses the `fmt` library to fill '{}' with remaining
arguments. Since only a single argument (the stack trace string) is
passed for formatting, naturally the `fmt::format` throws an exception,
that it is missing a format argument.
We could provide an overload which takes a single string, but that
defeats the purpose of `fmt::format` raising an exception in regular
code if we forget to pass an argument. Another solution is to escape the
whole stack trace string, so it is valid for formatting, but this only
complicates the handler even further. The simplest solution is to send
the stack trace to `stderr` and avoid logging altogether.
Simplify Shutdown, so it can be used in a signal handler
Reviewers: florijan, mferencevic, buda, mislav.bradac
Reviewed By: mferencevic, buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D474
Summary:
Since assertions should signify an abnormal program condition, it makes
sense for them to call `std::abort`. This way, we'll get a core dump
which can be inspected in a debugger.
Update utils/assert.hpp documentation
Reviewers: florijan, buda, mislav.bradac
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D475
Summary: An unpleasant race-condition detected. Solution proposed. It's not very pretty. Perhaps consider using the ConcurrentPushQueue. Not 100% sure, but it should make the GC code easier to work with.
Reviewers: buda, mislav.bradac, teon.banek, dgleich
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D469
Summary:
Remove utils/stacktrace/log.hpp
The single function defined in log.hpp is used only in
memgraph_bolt.cpp. Therefore, the function has been moved and the file
removed.
Move utils/stacktrace/stacktrace.hpp one level up
Move some logging from memgraph_bolt to Server
Reviewers: buda, dtomicevic
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D465
Summary:
This is an obvious bug, caused by an oversight. A test has been added
for this case.
Reviewers: florijan, mislav.bradac, buda
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D455
Summary:
- GC changed to evaluate old records w.r.t. the oldest transaction's id AND snapshot, as opposed to only id
- MVCC hints exp+aborted race condition prevented
- minor MVCC refactors and cleanups
- minor Transaction refactors and cleanups
Reviewers: buda, dgleich
Reviewed By: buda, dgleich
Subscribers: dtomicevic, pullbot
Differential Revision: https://phabricator.memgraph.io/D434
Summary: Alpha package scripts. Alpha version is going to be shipped within docker.
Reviewers: teon.banek, mferencevic
Reviewed By: teon.banek
Subscribers: pullbot, buda
Differential Revision: https://phabricator.memgraph.io/D436
Summary:
This fixes an issue when aggregations and/or group by expressions
weren't picked up from certain operators. In addition to that, we would
segfault in cases when the `has_aggregation_` is empty. For example,
function calls without arguments: `RETURN PI()`.
Test aggregations inside some operators
Reviewers: florijan, mislav.bradac, buda
Reviewed By: mislav.bradac
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D425
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:
Permute query parts.
Permute matching only by selecting the starting node.
Flip the expansion when expanding from the other node.
Split planner into rule_based_planner and variable_start_planner
Use symbol hash when collecting expansion nodes
Multiple node atoms may point to the same symbol, and we could generate
multiple starting positions per atom which are the same. Using symbol
hash and equality prevents generating those redundant plans.
Correctly permute optional and merge matchings
Test VariableStartPlanner
Reviewers: florijan, mislav.bradac, buda, lion
Reviewed By: florijan, buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D417
Summary:
We would redundantly generate an Expansion for the first node if it was part of
an expand. For example, the pattern `(n) -[r]- (m)` would generate
`Expansion{n}` and `Expansion{n, r, m}`, when only the latter is enough. This
change corrects that behaviour by dropping the first Expansion.
Reviewers: florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D412
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
