Summary:
For proper client interaction, we need to expose the (term_id, log_index)
pair for the transaction that's about to be replicated and we need to be able
to retrieve the status of a transaction defined by that pair. Transaction
status can be one of the following:
1) REPLICATED (self-explanatory)
2) WAITING (waiting for replication)
3) ABORTED (self-explanatory)
4) INVALID (received request with either invalid term_id or invalid log_index)
Reviewers: mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2201
Summary:
The first 2 tuple elements are redundant as they are available through
EdgeAccessor and they needlessly complicate the usage of the API.
Reviewers: mtomic, mferencevic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2200
Summary:
The newly added methods are modeled after the ones being added in C++20 to
`std::pmr::polymorphic_allocator`.
Reviewers: mtomic, mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2197
Summary:
`lock_guard` is holding vertex lock while we're deleting the vertex,
and then it might try to unlock it in its destructor and access freed memory.
Reviewers: teon.banek, mferencevic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2192
Summary:
This is a preparation step in case we want to have a custom allocator in
SkipList. For example, pool based allocator for SkipListNode.
Introduction of MemoryResource and removal of `calloc` has reduced the
performance a bit according to micro benchmarks. This performance hit is
not visible on benchmarks which do more concurrent operations.
Reviewers: mferencevic, mtomic
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2140
Summary:
This change implements full edges support in storage v2. Edges can be created
and deleted. Support for detach-deleting vertices is added and regular vertex
deletion verifies existance of edges.
Reviewers: mtomic, teon.banek
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2180
Summary:
Instead of calling the wanted method, this diff takes copies of both `is_replicated(x)` and `is_active(x)` results so that they can't change during the method execution.
The problem with the previous implementation was that the information about a
log could change during two consecutive queries as ilustrated in the example
below.
```
Thread 1 Thread2
rlog->set_active(1);
if (rlog->is_replicated(1)) return true;
rlog->set_replicated(1);
if (rlog->is_active(1)) return false;
throw InvalidLogReplicationLookup();
```
The snippet above would throw as we don't have any information about the log
`1`, because the `set_replicated` call would "shadow" the active bit.
Reviewers: ipaljak
Reviewed By: ipaljak
Subscribers: pullbot, mferencevic
Differential Revision: https://phabricator.memgraph.io/D2165
Summary:
We forgot to update `modified_vertices` in the case when the vertex
has an empty version chain. It didn't manifest before because it was impossible
for a vertex to have an empty version chain without garbage collection.
Reviewers: mferencevic, teon.banek
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2154
Summary:
We forgot to add the newly created vertex into `modified_vertices`
list.
Reviewers: teon.banek, mferencevic
Reviewed By: mferencevic
Differential Revision: https://phabricator.memgraph.io/D2153
Summary:
Initial implementation of new storage engine. It implements snapshot isolation
for transactions. All changes in the database are stored as deltas instead of
making full copies. Currently, the storage supports full transaction
functionality (commit, abort, command advancement). Also, support has been
implemented only for vertices that have only labels.
Reviewers: teon.banek, mtomic
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2138
Summary:
Micro benchmarks show some minor variations compared to the previous
commit. Smaller cases are a bit worse while larger data cases are a bit
better.
Reviewers: mtomic, mferencevic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2136
Summary:
Micro benchmarks show improvements in performance of MapLiteral from 5%
to 40% depending on the size of the input. On the other hand, a sequence
of AdditionOperators behaves the same with both allocation schemes.
Reviewers: mtomic, mferencevic, msantl
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2132
Summary:
The global variable may hide the fact that it uses the default
utils::NewDeleteResource() for allocations.
Reviewers: mtomic, llugovic, mferencevic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2121
Summary:
Split up `process-file` so that looking at the generated code for an LCP form is
easier from the REPL.
`process-lcp`, `generate-hpp` and `generate-cpp` now perform the generation of
C++ code, but take a list of "C++ elements" (the results of LCP forms) as input
and write their output to streams. They do no reading/evaluating of LCP forms of
their own.
`read-lcp` and `read-lcp-file` are used to read and evaluate a stream of LCP
forms. The latter is a specialized version for file streams which also reports
the position of the form within the file when an error happens.
`process-lcp-string` and `process-lcp-file` are convenient wrappers around the
main functionality that take a string (file) and output to strings (files).
Using `read-lcp` and `read-lcp-file` they process LCP forms and pass them off to
`process-lcp` for code generation.
Reviewers: mtomic, teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2097
Summary:
`dump()` awesome Memgraph function is removed.
`mg_dump` executable now uses "dump database" command instead of "return dump()"
and dumps database to standard output instead of a file.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2122
Summary:
Stream queries to the output table.
For effective output streaming, a simple operator, `OutputTableStream` is implemented which fetches and
produces a single row on each Pull.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2099
Summary:
This is unfortunately needed in the C++17 standard, so that the
allocator is correctly propagated to elements of pair which respect the
"Uses Allocator" protocol. C++20 standard resolves this issue, but we
still have a long way before it is released and implemented by the
compiler and standard library vendors.
Reviewers: mtomic, llugovic, mferencevic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2107
Summary: Forward declare the needed struct and include in the correct file.
Reviewers: ipaljak
Reviewed By: ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2110
Summary:
This diff only introduces a MemoryResource member to TypedValue and correctly
propagates through various constructors and assignments. At the moment,
MemoryResource is not used to actually allocate anything.
Reviewers: mtomic, llugovic, mferencevic, msantl
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2085
Summary:
HA should now support constraints in the same way the SM version does.
I only tested this thing manually, but I plan to add a new integration test for
this also.
Reviewers: ipaljak, vkasljevic, mferencevic
Reviewed By: ipaljak, mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2083
Summary:
Implemented a simple dump executable which runs `RETURN dump()` on the database using Bolt protocol.
The `dump()` function returns a list of openCypher queries needed for database reconstruction (note: in the future we should use more appropriate method that supports streaming of data).
Reviewers: teon.banek, mferencevic
Reviewed By: teon.banek
Subscribers: pullbot, mferencevic
Differential Revision: https://phabricator.memgraph.io/D2067
Summary:
Fix condition variable notifications
Fix vote requested invalid memory access (size off by one)
Fix blocking wait in RaftPeer while candidate
Don't copy large log entries when only the term is needed
Reviewers: ipaljak, msantl
Reviewed By: ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2088
Summary:
Preparing unique constraint code to be implemented in HA. To do so, I'm
moving everything to `stograge/common/` folder. I also added a new header,
`gid.hpp` which does a `ifdef` include of the correct `gid.hpp` based on the
product.
Reviewers: ipaljak, mferencevic, vkasljevic, teon.banek
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2079
Summary:
Instead of asking rocksdb for snapshot metadata, keep it in memory for
faster access.
Reviewers: ipaljak
Reviewed By: ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2075
Summary:
During it's leadership, one peer can receive RPC messages from other peers that his reign is over.
The problem is when this happens during a transaction commit.
This is handled in the following way.
If we're the current leader and we want to commit a transaction, we need to make sure the Raft Log is replicated before we can tell the client that the transaction is committed.
During that wait, we can only notice that the replication takes too long, and we report that with `LOG(WARNING)` messages.
If we change the Raft mode during the wait, our Raft implementation will internally commit this transaction, but won't be able to acquire the Raft lock because the `db.Reset` has been called.
This is why there is an manual lock acquire. If we pick up that the `db.Reset` has been called, we throw an `UnexpectedLeaderChangeException` exception to the client.
Another thing with long running transactions, if someone decides to kill a `memgraph_ha` instance during the commit, the transaction will have `abort` hint set. This will cause the `src/query/operator.cpp` to throw a `HintedAbortError`. We need to catch this during the shutdown, because the `memgraph_ha` isn't dead from the user perspective, and the transaction wasn't aborted because it took too long, but we can differentiate between those two.
Reviewers: mferencevic, ipaljak
Reviewed By: mferencevic, ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1956
Summary:
Micro benchmarks show no change compared to global new & delete. This is
to be expected, because Unwind relies only on `std::vector` which ought
to reserve the memory in reasonable chunks.
Reviewers: mtomic, llugovic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2064
Summary:
Micro benchmarks show an improvement to performance of about 10%
compared to global new & delete.
Reviewers: mtomic, llugovic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2061
Summary: We should now exchange around O(log(n)) messages to get a follower that is n transactions behind back in sync.
Reviewers: msantl, mferencevic
Reviewed By: msantl
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2051
