After fcb8d040 ("treewide: use Software Package Data Exchange
(SPDX) license identifiers"), many dual-licensed files were
left with empty comments on top. Remove them to avoid visual
noise.
Closes#10562
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
This db argument is only needed to be pushed into
cdc::is_log_for_some_table() helper. All callers already have
the d._d.::database at hands and convert it into .real_database()
call-time, so this patch effectively generalizes those calls to
the .real_database().
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
It's now called with d._d.::database converted to .real_database()
right in the argument passing, so this change can be treated as
the generalization of that .real_database() call.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Straightforward replacement. Internals of the has_column_family_access()
temporarily get .real_database(), but it will be changed soon.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Straightforward replacement. Internals of the has_keyspace_access()
temporarily get .real_database(), but it will be changed soon.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Move replica-oriented classes to the replica namespace. The main
classes moved are ::database, ::keyspace, and ::table, but a few
ancillary classes are also moved. There are certainly classes that
should be moved but aren't (like distributed_loader) but we have
to start somewhere.
References are adjusted treewide. In many cases, it is obvious that
a call site should not access the replica (but the data_dictionary
instead), but that is left for separate work.
scylla-gdb.py is adjusted to look for both the new and old names.
The database, keyspace, and table classes represent the replica-only
part of the objects after which they are named. Reading from a table
doesn't give you the full data, just the replica's view, and it is not
consistent since reconciliation is applied on the coordinator.
As a first step in acknowledging this, move the related files to
a replica/ subdirectory.
Timeout config is now stored in each connection, so there's no point
in tracking it inside each query as well. This patch removes
timeout_config from query_options and follows by removing now
unnecessary parameters of many functions and constructors.
It is called from cql3/statements' check_access methods and from thrift
handlers. The former have proxy argument from which they can get the
database. The latter already have the database itself on board.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
These alterations cannot break the database irreparably, so allow
them.
Expand command_desc as required.
Add a type (rather than command_desc) parameter to
has_column_family_access() to minimize code changes.
Fixes#7057
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
This patch set adds a few new features in order to fix issue
The list of changes is briefly as follows:
- Add a new `LWT` flag to `cql3::prepared_metadata`,
which allows clients to clearly distinguish betwen lwt and
non-lwt statements without need to execute some custom parsing
logic (e.g. parsing the prepared query with regular expressions),
which is obviously quite fragile.
- Introduce the negotiation procedure for cql protocol extensions.
This is done via `cql_protocol_extension` enum and is expected
to have an appropriate mirroring implementation on the client
driver side in order to work properly.
- Implmenent a `LWT_ADD_METADATA_MARK` cql feature on top of the
aforementioned algorithm to make the feature negotiable and use
it conditionally (iff both server and client agrees with each
other on the set of cql extensions).
The feature is meant to be further utilized by client drivers
to use primary replicas consistently when dealing with conditional
statements.
* git@github.com:ManManson/scylla feature/lwt_prepared_meta_flag_2:
lwt: introduce "LWT" flag in prepared statement metadata
transport: introduce `cql_protocol_extension` enum and cql protocol extensions negotiation
The patch introduces two new features to aid with negotiating
protocol extensions for the CQL protocol:
- `cql_protocol_extensions` enum, which holds all supported
extensions for the CQL protocol (currently contains only
`LWT_ADD_METADATA_MARK` extension, which will be mentioned
below).
- An additional mechainsm of negotiating cql protocol extensions
to be used in a client connection between a scylla server
and a client driver.
These extensions are propagated in SUPPORTED message sent from the
server side with "SCYLLA_" prefix and received back as a response
from the client driver in order to determine intersection between
the cql extensions that are both supported by the server and
acknowledged by a client driver.
This intersection of features is later determined to be a working
set of cql protocol extensions in use for the current `client_state`,
which is associated with a particular client connection.
This way we can easily settle on the used extensions set on
both sides of the connection.
Currently there is only one value: `LWT_ADD_METADATA_MARK`, which
regulates whether to set a designated bit in prepared statement
metadata indicating if the statement at hand is an lwt statement
or not (actual implementation for the feature will be in a later
patch).
Each extension can also propagate some custom parameters to the
corresponding key. CQL protocol specification allows to send
a list of values with each key in the SUPPORTED message, we use
that to pass parameters to extensions as `PARAM=VALUE` strings.
In case of `LWT_ADD_METADATA_MARK` it's
`SCYLLA_LWT_OPTIMIZATION_META_BIT_MASK` which designates the
bitmask for LWT flag in prepared statement metadata in order to be
used for lookup in a client library. The associated bits of code in
`cql3::prepared_metadata` are adjusted to accomodate the feature.
The value for the flag is chosen on purpose to be the last bit
in the flags bitset since we don't want to possibly clash with
C* implementation in case they add more possible flag values to
prepared metadata (though there is an issue regarding that:
https://issues.apache.org/jira/browse/CASSANDRA-15746).
If it's fixed in upstream Cassandra, then we could synchronize
the value for the flag with them.
Also extend the underlying type of `flag` enum in
`cql3::prepared_metadata` to be `uint32_t` instead of `uint8_t`
because in either case flags mask is serialized as 32-bit integer.
In theory, shard-awareness extension support also should be
reworked in terms of provided minimal infrastructure, but for the
sake of simplicity, this is left to be done in a follow-up some
time later.
This solution eliminates the need to assume that all the client
drivers follow the CQL spec carefully because scylla-specific
features and protocol extensions could be enabled only in case both
server and client driver negotiate the supported feature set.
Tests: unit(dev, debug)
Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>
No change in the implementation since it was already copying the
string. Taking a std::string_view is just a bit more flexible.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
client_state is shared between requests and tracing state is per
request. It is not safe to use the former as a container for the later
since a state can be overwritten prematurely by subsequent requests.
This change introduces system.clients table, which provides
information about CQL clients connected.
PK is the client's IP address, CK consists of outgoing port number
and client_type (which will be extended in future to thrift/alternator/redis).
Table supplies also shard_id and username. Other columns,
like connection_stage, driver_name, driver_version...,
are currently empty but exist for C* compatibility and future use.
This is an ordinary table (i.e. non-virtual) and it's updated upon
accepting connections. This is also why C*'s column request_count
was not introduced. In case of abrupt DB stop, the table should not persist,
so it's being truncated on startup.
Resolves#4820
LWT is much more efficient if a request is processed on a shard that owns
a token for the request. This is because otherwise the processing will
bounce to an owning shard multiple times. The patch proposes a way to
move request to correct shard before running lwt. It works by returning
an error from lwt code if a shard is incorrect one specifying the shard
the request should be moved to. The error is processed by transport code
that jumps to a correct shard and re-process incoming message there.
I used the following as a reference:
https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/virtual/ClientsTable.java
At this moment there is only info about IP, clients outgoing port,
client 'type' (i.e. CQL/thrift/alternator), shard ID and username.
Column `request_count' is NOT present and CK consists of
(`port', `client_type'), contrary to what C*'s has: (`port').
Code that notifies `system.clients` about new connections goes
to top-level files `connection_notifier.*`. Currently only CQL
clients are observed, but enum `client_type` can be used in future
to notify about connections with other protocols.
LWT is much more efficient if a request is processed on a shard that owns
a token for the request. This is because otherwise the processing will
bounce to an owning shard multiple times. The patch proposes a way to
move request to correct shard before running lwt. It works by returning
an error from lwt code if a shard is incorrect one specifying the shard
the request should be moved to. The error is processed by transport code
that jumps to a correct shard and re-process incoming message there.
_user cannot outlive client_state class instance, so there is no point
in holding it in shared_ptr.
Tested: debug test.py and dtest auth_test.py
Message-Id: <20191128131217.26294-5-gleb@scylladb.com>
If each client_state has its own copy of the variable two clients may
generate timestamps that clash and needlessly create contention. Making
the variable shared between all client_state on the same shard will make
sure this will not happen to two clients on the same shard. It may still
happen for two client on two different shards or two different nodes.
Paxos needs a unique timestamp that is greater than some other
timestamp, so that the next round had more chances to succeed.
Add a function that returns such a timestamp.
Commit 7e3805ed3d removed the load balancing code from cql
server, but it did not remove most of the craft that load balancing
introduced. The most of the complexity (and probably the main reason the
code never worked properly) is around service::client_state class which
is copied before been passed to the request processor (because in the past
the processing could have happened on another shard) and then merged back
into the "master copy" because a request processing may have changed it.
This commit remove all this copying. The client_request is passed as a
reference all the way to the lowest layer that needs it and it copy
construction is removed to make sure nobody copies it by mistake.
tests: dev, default c-s load of 3 node cluster
Message-Id: <20190906083050.GA21796@scylladb.com>
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.
Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.
Scylla now requires GCC 8 to compile.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
Many headers don't really need to include database.hh, the include can
be replaced by forward declarations and/or including the actually needed
headers directly. Some headers don't need this include at all.
Each header was verified to be compilable on its own after the change,
by including it into an empty `.cc` file and compiling it. `.cc` files
that used to get `database.hh` through headers that no longer include it
were changed to include it themselves.
sprint() recently became more strict, throwing on sprint("%s", 5). Replace
with the more modern format().
Mechanically converted with https://github.com/avikivity/unsprint.
-O1 complains that client_state::_remote_addr is not initialized
(and it is right). The call site is tracing, which likely won't be
invoked for internal queries, but still.
Message-Id: <20180401150410.13651-1-avi@scylladb.com>
This patch came about because of an important (and obvious, in
hindsight) realization: instances of the authorizer, role manager, and
authenticator are clients for access-control state and not the state
itself. This is reflected directly in Scylla: `auth::service` is
sharded across cores and this is possible because each instance queries
and modifies the same global state.
To give more examples, the value of an instance of `std::vector<int>` is
the structure of the container and its contents. The value of `int
file_descriptor` is an identifier for state maintained elsewhere.
Having watched an excellent talk by Herb Sutter [1] and having read an
informative blog post [2], it's clear that a member function marked
`const` communicates that the observable state of the instance is not
modified.
Thus, the member functions of the role-manager, authenticator, and
authorizer clients should not be marked `const` only if the state of the
client itself is observably changed. By this principle, member functions
which do not change the state of the client, but which mutate the global
state the client is associated with (for example, by creating a role)
are marked `const`.
The `start` (and `stop`) functions of the client have the dual role of
initializing (finalizing) both the local client state and the
external state; they are not marked `const`.
[1] https://herbsutter.com/2013/01/01/video-you-dont-know-const-and-mutable/
[2] http://talesofcpp.fusionfenix.com/post-2/episode-one-to-be-or-not-to-be-const
Previously, a "data" auth. resource knew how to check it's own existence by
accessing a global variable.
This patch accomplishes two things: it adds existence checking to all
kinds of resources, and moves these checks outside of `auth::resource`
itself and into `auth::service` (so that global variables are no longer
accessed).
This has the dual benefit of not enforcing copying on implementations of
the abstract interface and also limiting unnecessary copies.
As usual with Seastar, we follow the convention that a reference
parameter to a function is assumed valid for the duration of the
`future` that is returned. `do_with` helps here.
By adding some constants for root resources, we can avoid using
`seastar::do_with` at some call-sites involving `resource` instances.
client_state used in the process_request_one(...) contains all sorts of information irrelevant
to the caller (process_request(...)), e.g. Tracing state. Therefore instead of returning
the whole client_state object (which becomes even a bigger problem if process_one(...) and process_request_one(...)
are executed on different shards) we will return only the pieces of information we really need.
To do that we introduce a new class - processing_result, which is cross-shard-access-ready to begin with.
We are going to return a instance of this new class from the process_request_one(...).
Fixes#2351
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Move the requests-handling-related state into the client_state. This is needed to properly
define the interface between the process_request(...) and process_request_one(...).
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
