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
In order to implement service level cql queries, the queries objects
needs access to the service_level_controller object when processing.
This patch adds this access by embedding it into the query state object.
In order to accomplish the above the query processor object needs an
access to service_level_controller in order to instantiate the query state.
Message-Id: <68f5a7796068a49d9cd004f1cbf34bdf93b418bc.1609234193.git.sarna@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.
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.
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.
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>
Current cql transport code acquire a permit before processing a query and
release it when the query gets a reply, but some quires leave work behind.
If the work is allowed to accumulate without any limit a server may
eventually run out of memory. To prevent that the permit system should
account for the background work as well. The patch is a first step in
this direction. It passes a permit down to storage proxy where it will
be later hold by background work.
Adding this method allows to use tracing helper functions
and remove the no longer needed accessors in the query_state.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Sometimes we want to be able to set "params" map after we
started a tracing session, e.g. when the parameters values,
like a consistency level parsed from the "options" part of a binary frame,
are available only after some heavy part of a flow we would like
to trace.
This patch includes the following changes:
- No longer pass a map to the begin().
- Limit the parameters to the known set.
- Define a method to set each such parameter and save its
value till the final sstring->sstring map is created.
- Construct the final sstring->sstring map in the destructor of the trace_state
object in order to defer all the formatting to be after the traced flow.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
In names of functions and variables:
s/flush_/write_/
s/store_/write_/
In a i_tracing_backend_helper:
s/flush()/kick()/
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Instrument a coordinator of a SELECT query to send tracing session
info to the corresponding replica Nodes.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
- Store a trace state inside a client_state.
- Start tracing in a cql_server::connection::process_query().
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Since 4641dfff24, query_state keeps a
copy of client_state, not a reference. Therefore _cl is no longer
updated by queries using _qp. Fix by using the client_state from _qp.
Fixes#525.
In preparation for processing CQL requests on different core than where
the connection lives in, copy client state to query state for
processing and merge back the results after we're done.
Signed-off-by: Pekka Enberg <penberg@scylladb.com>
