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
Now that get_status returns string_view, just compare it with a const char*
rather than making a sstring out of it, and consequently, can be marked noexcept.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
get_status doesn't need to allocate a sstring, it can just
return a std::string_view to the status string, if found.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Although std::map::find is not guaranteed to be noexcept
it depends on the comperator used and in this case comparing application_state
is noexcept. Therefore, we can safely mark get_application_state_ptr noexcept.
is_cql_ready depends on get_application_state_ptr and otherwise
handles an exceptions boost::lexical_cast so it can be marked
noexcept as well.
Signed-off-by: Benny Halevy <bhalevy@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>
Application states of each node are versioned per-node with a pair of
generation number (more significant) and value version. Generation
number uniquely identifies the life time of a scylla
process. Generation number changes after restart. Value versions start
from 0 on each restart. When a node gets updates for application
states, it merges them with its view on given node. Value updates with
older versions are ignored.
Gossiper processes updates only on shard 0, and replicates value
updates to other shards. When it sees a value with a new generation,
it correclty forgets all previous values. However, non-zero shards
don't forget values from previous generations. As a result,
replication will fail to override the values on non-zero shards when
generation number changes until their value version exceeds the
version prior to the restart.
This will result in incorrect STATUS for non-seed nodes on non-zero
shards. When restarting a non-seed node, it will do a shadow gossip
round before setting its STATUS to NORMAL. In the shadow round it will
learn from other nodes about itself, and set its STATUS to shutdown on
all shards with a high value version. Later, when it sets its status
to NORMAL, it will override it only on shard 0, because on other
shards the version of STATUS is higher.
This will cause CQL truncate to skip current node if the coordinator
runs on non-zero shards.
The fix is to override the entries on remote shards in the same way we
do on shard 0. All updates to endpoint states should be already
serialized on shard 0, and remote shards should see them in the same
order.
Introduced in 2d5fb9dFixes#3798Fixes#3694
It is faster than gossiper::is_normal because it avoids to do search in
the std::map<application_state, versioned_value>. It is useful for the
code in the fast path which needs to query if a node is in NORMAL
status.
Fixes#3500
Message-Id: <42db91fa4108f9f4fcf94fed3ec403ccf35d15e9.1528354644.git.asias@scylladb.com>
Broken in f570e41d18.
Not replicating this may cause coordinator to treat a node which is
down as alive, or vice verse.
Fixes regression in dtest:
consistency_test.py:TestAvailability.test_simple_strategy
which was expected to get "unavailable" exception but it was getting a
timeout.
Message-Id: <1510666967-1288-1-git-send-email-tgrabiec@scylladb.com>
storage_service depends on endpoint states to be replicated to all
shards before token metadata is replicated. Currently this is taken
care of by storage_service::replicate_to_all_cores(), invoked from
storage_service's change listener. It copies whole endpoint state map,
which is expensive in large clusters. It's more efficient to replicate
only incremental changes, and only once, rather than for each
application state.
The expire time which is used to decide when to remove a node from
gossip membership is gossiped around the cluster. We switched to steady
clock in the past. In order to have a consistent time_point in all the
nodes in the cluster, we have to use wall clock. Switch to use
system_clock for gossip.
Fixes#1704
The only reason we needed it is to make
_application_state[key] = value
work.
With the current default constructor, we increase the version number
needlessly. To fix and to be safe, remove the default constructor
completely.
This is a long-awaited cleanup. Gossiper code runs every second, it is
not performance sensitive, so it does not make much sense to stick to
lowres db_clock, use high_resolution_clock instead.
