- Only IN_MEMORY_ANALYTICAL requires unique lock during snapshot
- GC in some cases will be provide with unique lock
- This fact can be used for optimisations
- In all other cases, optimisations should be done with alternative
check. Not via getting a unique lock
Also:
- Faster property lookup
- Faster index iteration (better conditional branching)
* Split queries into system and data queries
* System queries are sequentially executed and generate separate transaction deltas
* System transaction try locks for 100ms
* last_commited_system_ts saved to DBMS durability
* Replicating CREATE/DROP DATABASE
* Sending a system snapshot if REPLICA behind
* Passing a copy of the gatekeeper::access as std::any to all functions that could call an async execution
* Removed delete_on_drop flag (we now always delete on drop)
* Using UUID as the directory name for databases
* DBMS durability update (added versioning and salient information)
* Automatic migration from previous version
* Interpreter can run some queries without a target database
* SHOW REPLICA returns the status of the currently active DB
* Returning UUID instead of db name in the RPC responses
* Using UUIDs for database specification in RPC (not name)
* FrequentCheck forces update on reconnect
* TimestampRpc will detect if a replica is behind, and will update client's state
* Safer SLK reads
* Split SHOW DATABASES in two SHOW DATABASES (list of current databases) and SHOW DATABASE a single string naming the current database
---------
Co-authored-by: Gareth Lloyd <gareth.lloyd@memgraph.io>
* Fix up REPLICA GetInfo and CreateSnapshot
Subtle bug where these actions were using the incorrect transactional
access while in REPLICA role. This casued timestamp to be incorrectly
bumped, breaking REPLICA from doing replication.
* Delay DNS resolution
Rather than resolve at endpoint creation, we will instread resolve only
on Socket connect. This allows k8s deployments to change their IP during
pod restarts.
* Minor sonarsource fixes
---------
Co-authored-by: Andreja <andreja.tonev@memgraph.io>
Co-authored-by: DavIvek <david.ivekovic@memgraph.io>
Fixes root cause of a cascade of failures in replication code:
- Replica handling of deleting an edge is now corrected. Now tolerant of multiple edges of the same relationship type.
- Improved robustness: correct exception handling around failed stream of current WAL file. This now means a REPLICA failure will no longer prevent transactions on MAIN from performing WAL writes.
- Slightly better diagnostic messages, not user friendly but helps get developer to correct root cause quicker.
- Proactively remove vertex+edges during Abort rather than defer to GC to do that work, this included fixing constraints and indexes to be safe.
Co-authored-by: Andreja Tonev <andreja.tonev@memgraph.io>
Single (instance level) connection to a replica (messages from all databases get multiplexed through it)
ReplicationClient split in two: ReplicationClient and ReplicationStorageClient
New ReplicationClient, moved under replication, handles the raw connection, owned by MainRoleData
ReplicationStorageClient handles the storage <-> replica state machine and holds to a stream
Removed epoch and storage from *Clients
rpc::Stream proactively aborts on error and sets itself to a defunct state
Removed HandleRpcFailure, instead we simply log the error and let the FrequentCheck handle re-connection
replica_state is now a synced variable
ReplicaStorageClient state machine bugfixes
Single FrequentCheck that goes through DBMS
Moved ReplicationState under DbmsHandler
Moved some replication startup logic under the DbmsHandler's constructor
Removed InMemoryReplicationClient
CreateReplicationClient has been removed from Storage
Simplified GetRecoverySteps and made safer
---------
Co-authored-by: Gareth Lloyd <gareth.lloyd@memgraph.io>
There might be a performance impect of updating the metadata store on
bulk operations. Hence this flag which is disabling the collection by
default. If the queries to obtain the information are called with this
flag disabled, the database will throw an exception.
The objects stored_node_labels_ and stored_edge_types_ can be accesses
through separate threads but it was not safe to do so. This commit
replaces the standard containers with threadsafe ones.
In order to get the required metadata in constant time we need to keep
track of the node labels and edge types that were ever present in the
database. This is done by the two axuiliary datastructures that are
present in the storage instances. The ability to get this metadata is
propagated to the DBAccessor class, which the query modules can interact
with.
* Interpreter transaction ID decoupled from storage transaction ID
* Transactional scope for indices, statistics and constraints
* Storage::Accessor now has 2 modes (unique and shared)
* Introduced ResourceLock to fix pthread mutex problems
* Split InfoQuery in two: non-transactional SystemInfoQuery and transactional DatabaseInfoQuery
* Replicable and durable statistics
* Bumped WAL/Snapshot versions
* Initial implementation of the Lamport clock
---------
Co-authored-by: Andreja Tonev <andreja.tonev@memgraph.io>
It is possible for multiple read only queries to be accessing the same
sequence of vertices/edges. The reader mode of the spin lock will ensure
multiple threads can make progress at the same time.
