Recently, the cql_server_config::max_concurrent_requests field was
changed to be an updateable_value, so that it is updated when the
corresponding option in Scylla's configuration is live-reloaded.
Unfortunately, due to how cql_server is constructed, this caused
cql_server instances on all shards to store an updateable_value which
pointed to an updateable_value_source on shard 0. Unsynchronized
cross-shard memory operations ensue.
The fix changes the cql_server_config so that it holds a function which
creates an updateable_value appropriate for the given shard. This
pattern is similar to another, already existing option in the config:
get_service_memory_limiter_semaphore.
This fix can be reverted if updateable_value becomes safe to use across
shards.
Tests: unit(dev)
Fixes: #7310
The newly introduced parameter - max_concurrent_requests_per_shard
- can be used to limit the number of in-flight requests a single
coordinator shard can handle. Each surplus request will be
immediately refused by returning OverloadedException error to the client.
The default value for this parameter is large enough to never
actually shed any requests.
Currently, the limit is only applied to CQL requests - other frontends
like alternator and redis are not throttled yet.
C++20 introduced `contains` member functions for maps and sets for
checking whether an element is present in the collection. Previously
the code pattern looked like:
<collection>.find(<element>) != <collection>.end()
In C++20 the same can be expressed with:
<collection>.contains(<element>)
This is not only more concise but also expresses the intend of the code
more clearly.
This commit replaces all the occurences of the old pattern with the new
approach.
Tests: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <f001bbc356224f0c38f06ee2a90fb60a6e8e1980.1597132302.git.piotr@scylladb.com>
Merged pull request https://github.com/scylladb/scylla/pull/6910
by Wojciech Mitros:
This patch enables selecting more than 2^32 rows from a table. The change
becomes active after upgrading whole cluster - until then old limits are
used.
Tested reading 4.5*10^9 rows from a virtual table, manually upgrading a
cluster with ccm and performing cql SELECT queries during the upgrade,
ran unit tests in dev mode and cql and paging dtests.
tests: add large paging state tests
increase the maximum size of query results to 2^64
Currently, we cannot select more than 2^32 rows from a table because we are limited by types of
variables containing the numbers of rows. This patch changes these types and sets new limits.
The new limits take effect while selecting all rows from a table - custom limits of rows in a result
stay the same (2^32-1).
In classes which are being serialized and used in messaging, in order to be able to process queries
originating from older nodes, the top 32 bits of new integers are optional and stay at the end
of the class - if they're absent we assume they equal 0.
The backward compatibility was tested by querying an older node for a paged selection, using the
received paging_state with the same select statement on an upgraded node, and comparing the returned
rows with the result generated for the same query by the older node, additionally checking if the
paging_state returned by the upgraded node contained new fields with correct values. Also verified
if the older node simply ignores the top 32 bits of the remaining rows number when handling a query
with a paging_state originating from an upgraded node by generating and sending such a query to
an older node and checking the paging_state in the reply(using python driver).
Fixes#5101.
The new port is configurable from scylla.yaml and defaults to 19042
(unencrypted, unless client configures encryption options and omits
`native_shard_aware_transport_port_ssl`).
Two "SUPPORTED" tags are added: "SCYLLA_SHARD_AWARE_PORT" and
"SCYLLA_SHARD_AWARE_PORT_SSL". For compatibility,
"SCYLLA_SHARDING_ALGORITHM" is still kept.
Fixes#5239
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>
There is no point to hold prepared_metadata in result_message::prepared
as a shared_ptr since their lifetime match.
Message-Id: <20200610113217.GF335449@scylladb.com>
We use boost::bimap for bi-directional conversion from protocol type
encodings to type objects.
Unfortunately, boost::bimap isn't C++20-ready.
Fortunately, we only used one direction of the bimap.
Replace with plain old std::unordered_map<>.
Message-Id: <20200512103726.134124-1-avi@scylladb.com>
This removes the need to include reactor.hh, a source of compile
time bloat.
In some places, the call is qualified with seastar:: in order
to resolve ambiguities with a local name.
Includes are adjusted to make everything compile. We end up
having 14 translation units including reactor.hh, primarily for
deprecated things like reactor::at_exit().
Ref #1
All internal execution always uses query text as a key in the
cache of internal prepared statements. There is no need
to publish API for executing an internal prepared statement object.
The folded execute_internal() calls an internal prepare() and then
internal execute().
execute_internal(cache=true) does exactly that.
Rename an overloaded function process() to execute_direct().
Execute direct is a common term for executing a statement
that was not previously prepared. See, for example
SQLExecuteDirect in ODBC/SQL CLI specification,
mysql_stmt_execute_direct() in MySQL C API or EXECUTE DIRECT
in Postgres XC.
"
client_state is used simultaneously by many requests running in parallel
while tracing state pointer is per request. Both those facts do not sit
well together and as a result sometimes tracing state is being overwritten
while still been used by active request which may cause incorrect trace
or even a crash.
"
Fixes#5700.
* 'gleb/tracing_fix_v1' of github.com:scylladb/seastar-dev:
client_state: drop the pointer to a tracing state from client_state
transport: pass tracing state explicitly instead of relying on it been in the client_state
alternator: pass tracing state explicitly instead of relying on it been in the client_state
Multiple requests can use the same client_state simultaneously, so it is
not safe to use it as a container for a tracing state which is per request.
Currently next request may overwrite tracing state for previous one
causing, in a best case, wrong trace to be taken or crash if overwritten
pointer is freed prematurely.
Fixes#5700
query_processor is a central class, so reducing its includes
can reduce dependencies treewite. This patch removes includes
for parsed_statement, cf_statement, and untyped_result_set and
fixes up the rest of the tree to include what it lacks as a result
of these removals.
Sharding logic has been moved to token-sharding.hh some time ago.
This logic does not depend on partitioner any more so cpu_sharding_algorithm_name
can be safely moved to the header where rest of sharding logic lives.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
All three verbs that need to handle bounce_to_shard have almost
identical process_*() and process_*_on_shard() functions. Consolidate
them into one to reuse the code.
Before this patch the iterations over migration_notifier::_listeners
could race with listeners being added and removed.
The addition side is not modified, since it is common to add a
listener during construction and it would require a fairly big
refactoring. Instead, the iteration is modified to use indexes instead
of iterators so that it is still valid if another listener is added
concurrently.
For removal we use a rw lock, since removing an element invalidates
indexes too. There are only a few places that needed refactoring to
handle unregister_listener returning a future<>, so this is probably
OK.
Fixes#5541.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20200120192819.136305-1-espindola@scylladb.com>
This patch removes an implicit cql_server -> migration_manager
dependency, as the former's event notifier uses the latter
for notifications.
This dependency also breaks a loop:
storage_service -> cql_server -> migration_manager -> storage_service
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
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
Resolves#4820. Execution path in main.cc now cleans up system.clients
table if it exists (this is done on startup). Also, server.cc now calls
functions that notify about cql clients connecting/disconnecting.
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.
Currently query_options objects is passed to a trace stopping function
which makes it mandatory to make them alive until the end of the
query. The reason for that is to add prepared statement parameters to
the trace. All other query options that we want to put in the trace are
copied into trace_state::params_values, so lets copy prepared statement
parameters there too. Trace enabled case will become a little bit more
expensive but on the other hand we can drop a continuation that holds
query_options object alive from a fast path. It is safe to drop the call
to stop_foreground_prepared() here since The tracing will be stopped
in process_request_one().
Message-Id: <20191205102026.GJ9084@scylladb.com>
_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>
"
This patch series adds only UDF support, UDA will be in the next patch series.
With this all CQL types are mapped to Lua. Right now we setup a new
lua state and copy the values for each argument and return. This will
be optimized once profiled.
We require --experimental to enable UDF in case there is some change
to the table format.
"
* 'espindola/udf-only-v4' of https://github.com/espindola/scylla: (65 commits)
Lua: Document the conversions between Lua and CQL
Lua: Implement decimal subtraction
Lua: Implement decimal addition
Lua: Implement support for returning decimal
Lua: Implement decimal to string conversion
Lua: Implement decimal to floating point conversion
Lua: Implement support for decimal arguments
Lua: Implement support for returning varint
Lua: Implement support for returning duration
Lua: Implement support for duration arguments
Lua: Implement support for returning inet
Lua: Implement support for inet arguments
Lua: Implement support for returning time
Lua: Implement support for time arguments
Lua: Implement support for returning timeuuid
Lua: Implement support for returning uuid
Lua: Implement support for uuid and timeuuid arguments
Lua: Implement support for returning date
Lua: Implement support for date arguments
Lua: Implement support for returning timestamp
...
