Before these changes, we didn't specify which I/O scheduling
group commitlog instances in hinted handoff should use.
In this commit, we set it explicitly to the commitlog
scheduling group. The rationale for this choice is the fact
we don't want to cause a bottleneck on the write path
-- if hints are written too slowly, new incoming mutations
(NOT hints) might be rejected due to a too high number
of hints currently being written to disk; see
`storage_proxy::create_write_response_handler_helper()`
for more context.
(cherry picked from commit 6a7fb18b52)
Closesscylladb/scylladb#20094
In 58784cd, aa4b06a and other commits migrating
hinted handoff from IPs to host IDs (scylladb/scylladb#15567),
we started ignoring hint directories of invalid names,
i.e. those that represent neither an IP address, nor a host ID.
They remain on disk and are taken into account while computing
e.g. the total size of hints, but they're not used in any way.
These changes add logs informing the user when Scylla
encounters such a directory.
Closesscylladb/scylladb#17566
(cherry picked from commit a5528a2093)
Closesscylladb/scylladb#19892
Change the format of sync points to use host ID instead of IPs, to be
consistent with the use of host IDs in hinted handoff module.
Introduce sync point v3 format which is the same as v2 except it stores
host IDs instead of IPs.
The encoding of sync points now always uses the new v3 format with host
IDs.
The decoding supports both formats with host IDs and IPs, so a sync point
contains now a variant of either types, and in the case of the new
format the translation from IP to host ID is avoided.
Before these changes, it could happen that Scylla initialized
endpoint managers for hint directories representing
* host IDs before migrating hinted handoff to using host IDs,
* IP addresses after the migration.
One scenario looked like this:
1. Start Scylla and upgrade the cluster to using host IDs.
2. Create, by hand, a hint directory representing an IP address.
3. Trigger changing the host filter in hinted handoff; it could
be achieved by, for example, restricting the set of data
centers Scylla is allowed to save hints for.
When changing the host filter, we browse the hint directories
and create endpoint managers if we can send hints towards
the node corresponding to a given hint directory. We only
accepted hint directories representing IP addresses
and host IDs. However, we didn't check whether the local node
has already been upgraded to host-ID-based hinted handoff
or not. As a result, endpoint managers were created for
both IP addresses and host IDs, no matter whether we were
before or after the migration.
These changes make sure that any time we browse the hint
directories, we take that into account.
Fixesscylladb/scylladb#19172
(cherry picked from commit c9bb0a4da6)
Closesscylladb/scylladb#19426
We want to verify that a hint directory is drained
when any of the nodes correspodning to it leaves
the cluster. The test scenario should happen before
the whole cluster has been migrated to
the host-ID-based hinted handoff, so when we still
rely on the mappings between hint endpoint managers
and the hint directories managed by them.
To make such a test possible, in these changes we
introduce an error injection rejecting incoming
hints. We want to test a scenario when:
1. hints are saved towards a given node -- node N1,
2. N1 changes its IP to a different one,
3. some other node -- node N2 -- changes its IP
to the original IP of N1,
4. hints are saved towards N2 and they are stored
in the same directory as the hints saved towards
N1 before,
5. we start draining N2.
Because at some point N2 needs to be stopped,
it may happen that some mutations towards
a distributed system table generate a hint
to N2 BEFORE it has finished changing its IP,
effectively creating another hint directory
where ALL of the hints towards the node
will be stored from there on. That would disturb
the test scenario. Hence, this error injection is
necessary to ensure that all of the steps in the
test proceed as expected.
(cherry picked from commit e855794327)
Before hinted handoff is migrated to using host IDs
to identify nodes in the cluster, we keep track
of mappings between hint endpoint managers
identified by host IDs and the hint directories
managed by them and represented by IP addresses.
As a consequence, it may happen that one hint
directory corresponds to multiple nodes
-- it's intended. See 64ba620 for more details.
Before these changes, we only started the draining
process of a hint directory if the node leaving
the cluster corresponded to that hint directory
AND was identified by the same host ID as
the hint endpoint manager managing that directory.
As a result, the draining did not always happen
when it was supposed to.
Draining should start no matter which of the nodes
corresponding to a hint directory is leaving
the cluster. This commit ensures that it happens.
(cherry picked from commit 745a9c6ab8)
The existing inet_address::to_string() calls fmt::format("{}", *this)
anyway. However, the to_string() method is declared in .cc file, while
form formatter is in the header and is equipeed with constexprs so
that converting an address to string is done as much as possible
compile-time.
Also, though minor, fmt::to_string(foo) is believed to be even faster
than fmt::format("{}", foo).
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#18712
Before these changes, if initializing endpoint
managers after the migration of hinted handoff
to host ID is done throws an exception, we
don't remove the flag indicating the migration
is still in progress. However, the migration
has, in practice, finished -- all of the
hint directories have been mapped to host IDs
and all of the nodes in the cluster are
host-ID-based. Because of that, it makes sense
to remove the flag early on.
If hinted handoff is still IP-based and there is
a hint directory representing an IP without
a corresponding mapping to a host ID in
`locator::token_metadata`, an attemp to initialize
its endpoint manager will result in a segmentation
fault. This commit prevents that.
This pull request introduces host ID in the Hinted Handoff module. Nodes are now identified by their host IDs instead of their IPs. The conversion occurs on the boundary between the module and `storage_proxy.hh`, but aside from that, IPs have been erased.
The changes take into considerations that there might still be old hints, still identified by IPs, on disk – at start-up, we map them to host IDs if it's possible so that they're not lost.
Refs scylladb/scylladb#6403Fixesscylladb/scylladb#12278Closesscylladb/scylladb#15567
* github.com:scylladb/scylladb:
docs: Update Hinted Handoff documentation
db/hints: Add endpoint_downtime_not_bigger_than()
db/hints: Migrate hinted handoff when cluster feature is enabled
db/hints: Handle arbitrary directories in resource manager
db/hints: Start using hint_directory_manager
db/hints: Enforce providing IP in get_ep_manager()
db/hints: Introduce hint_directory_manager
db/hints/resource_manager: Update function description
db/hints: Coroutinize space_watchdog::scan_one_ep_dir()
db/hints: Expose update lock of space watchdog
db/hints: Add function for migrating hint directories to host ID
db/hints: Take both IP and host ID when storing hints
db/hints: Prepare initializing endpoint managers for migrating from IP to host ID
db/hints: Migrate to locator::host_id
db/hints: Remove noexcept in do_send_one_mutation()
service: Add locator::host_id to on_leave_cluster
service: Fix indentation
db/hints: Fix indentation
We add an auxiliary function checking if a node
hasn't been down for too long. Although
`gms::gossiper` provides already exposes a function
responsible for that, it requires that its
argument be an IP address. That's the reason
we add a new function.
These changes migrate hinted handoff to using
host ID as soon as the corresponding cluster
feature is enabled.
When a node starts, it defaults to creating
directories naming them after IP addresses.
When the whole cluster has upgraded
to a version of Scylla that can handle
directories representing host IDs,
we perform a migration of the IP folders,
i.e. we try to rename them to host IDs.
Invalid directories, i.e. those that
represent neither an IP address, nor a host
ID, are removed.
During the migration, hinted handoff is
disabled. It is necessary because we have
to modify the disk's contents, so new hints
cannot be saved until the migration finishes.
Before these changes, resource manager only handled
the case when directories it browsed represented
valid host IDs. However, since before migrating
hinted handoff to using host IDs we still name
directories after IP addresses, that would lead
to exceptins that shouldn't happen.
We make resource manager handle directories
of arbitrary names correctly.
We start keeping track of mappings IP - host ID.
The mappings are between endpoint managers
(identified by host IDs) and the hint directories
managed by them (represented by IP addresses).
This is a prelude to handling IP directories
by the hint shard manager.
The structure should only be used by the hint
manager before it's migrated to using host IDs.
The reason for that is that we rely on the
information obtained from the structure, but
it might not make sense later on.
When we start creating directories named after
host IDs and there are no longer directories
representing IP addresses, there is no relation
between host IDs and IPs -- just because
the structure is supposed to keep track between
endpoint managers and hint directories that
represent IP addresses. If they represent
host IDs, the connection between the two
is lost.
Still using the data structure could lead
to bugs, e.g. if we tried to associate
a given endpoint manager's host ID with its
corresponding IP address from
locator::token_metadata, it could happen that
two different host IDs would be bound to
the same IP address by the data structure:
node A has IP I1, node A changes its IP to I2,
node B changes its IP to I1. Though nodes
A and B have different host IDs (because they
are unique), the code would try to save hints
towards node B in node A's hint directory,
which should NOT happen.
Relying on the data structure is thus only
safe before migrating hinted handoff to using
host IDs. It may happen that we save a hint
in the hint directory of the wrong node indeed,
but since migration to using host IDs is
a process that only happens once, it's a price
we are ready to pay. It's only imperative to
prevent it from happening in normal
circumstances.
We drop the default argument in the function's signature.
Also, we adjust the code of change_host_filter() to
be able to perform calls to get_ep_manager().
This commit introduces a new class responsible
for keeping track of mappings IP-host ID.
Before hinted handoff is migrated to using
host IDs, hint directories still have to
represent IP addresses. However, since
we identify endpoint managers by host IDs
already, we need to be able to associate
them with the directories they manage.
This class serves this purpose.
We expose the update lock of space watchdog
to be able to prevent it from scanning
hint directories. It will be necessary in an
upcoming commit when we will be renaming hint
directories and possibly removing some of them.
Race conditions are unacceptable, so resource
manager cannot be able to access the directory
during that time.
We add a function that will be used while
migrating hinted handoff to using host IDs.
It iterates over existing hint directories
and tries to rename them to the corresponding
host IDs. In case of a failure, we remove
it so that at the end of its execution
the only remaining directories are those
that represent host IDs.
The store_hint() method starts taking both an IP
and a host ID as its arguments. The rationale
for the change is depending on the stage of
the cluster (before an upgrade to the
host-ID-based hinted handdof and after it),
we might need to create a directory representing
either an IP address, or a host ID.
Because locator::topology can change in the
before obtaining the host ID we pass
and when the function is being executed,
we need to pass both parameters explicitly
to ensure the consistency between them.
We extract the initialization of endpoint managers
from the start method of the hint manager
to a separate function and make it handle directories
that represent either IP addresses, or host IDs;
other directories are ignored.
It's necessary because before Scylla is upgraded
to a version that uses host-ID-based hinted handoff,
we need to continue only managing IP directories.
When Scylla has been upgraded, we will need to handle
host ID directories.
It may also happen that after an upgrade (but not
before it), Scylla fails while renaming
the directories, so we end up with some of them
representing IP address, and some representing
host IDs. After these changes, the code handles
that scenario as well.
We change the type of node identifiers
used within the module and fix compilation.
Directories storing hints to specific nodes
are now represented by host IDs instead of
IPs.
While the function is marked as noexcept, the returned
future can in fact store an exception. We remove the
specifier to reflect the actual behavior of the
function.
before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we include `fmt/ranges.h` and/or `fmt/std.h`
for formatting the container types, like vector, map
optional and variant using {fmt} instead of the homebrew
formatter based on operator<<.
with this change, the changes adding fmt::formatter and
the changes using ostream formatter explicitly, we are
allowed to drop `FMT_DEPRECATED_OSTREAM` macro.
Refs scylladb#13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
in in {fmt} before v10, it provides the specialization of `fmt::formatter<..>`
for `std::string_view` as well as the specialization of `fmt::formatter<..>`
for `fmt::string_view` which is an implementation builtin in {fmt} for
compatibility of pre-C++17. and this type is used even if the code is
compiled with C++ stadandard greater or equal to C++17. also, before v10,
the `fmt::formatter<std::string_view>::format()` is defined so it accepts
`std::string_view`. after v10, `fmt::formatter<std::string_view>` still
exists, but it is now defined using `format_as()` machinery, so it's
`format()` method does not actually accept `std::string_view`, it
accepts `fmt::string_view`, as the former can be converted to
`fmt::string_view`.
this is why we can inherit from `fmt::formatter<std::string_view>` and
use `formatter<std::string_view>::format(foo, ctx);` to implement the
`format()` method with {fmt} v9, but we cannot do this with {fmt} v10,
and we would have following compilation failure:
```
FAILED: service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o
/home/kefu/.local/bin/clang++ -DFMT_DEPRECATED_OSTREAM -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -MF service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o.d -o service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -c /home/kefu/dev/scylladb/service/topology_state_machine.cc
/home/kefu/dev/scylladb/service/topology_state_machine.cc:254:41: error: no matching member function for call to 'format'
254 | return formatter<std::string_view>::format(it->second, ctx);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
/usr/include/fmt/core.h:2759:22: note: candidate function template not viable: no known conversion from 'seastar::basic_sstring<char, unsigned int, 15>' to 'const fmt::basic_string_view<char>' for 1st argument
2759 | FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
| ^ ~~~~~~~~~~~~
```
because the inherited `format()` method actually comes from
`fmt::formatter<fmt::string_view>`. to reduce the confusion, in this
change, we just inherit from `fmt::format<string_view>`, where
`string_view` is actually `fmt::string_view`. this follows
the document at
https://fmt.dev/latest/api.html#formatting-user-defined-types,
and since there is less indirection under the hood -- we do not
use the specialization created by `FMT_FORMAT_AS` which inherit
from `formatter<fmt::string_view>`, hopefully this can improve
the compilation speed a little bit. also, this change addresses
the build failure with {fmt} v10.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18299
The semantics of the function was accidentally
modified in 6e79d64. The consequence of the change
was that we didn't limit memory consumption:
the function always returned false for any node
different from the local node. The returned value
is used by storage_proxy to decide whether it
is able to store a hint or not.
This commit fixes the problem by taking other
nodes into consideration again.
Fixes#17636Closesscylladb/scylladb#17639
before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we define formatters for `hints::host_filter`. its
operator<< is preserved as it's still used by the homebrew generic
formatter for vector<>, which is in turn used by db/config.cc.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17347
get0() dates back from the days where Seastar futures carried tuples, and
get0() was a way to get the first (and usually only) element. Now
it's a distraction, and Seastar is likely to deprecate and remove it.
Replace with seastar::future::get(), which does the same thing.
This reverts commit 370fbd346c, reversing
changes made to 0912d2a2c6.
This makes scylla-manager mis-interpret the data_file_directories
somehow, issue #17078
Previously, utils::directories::set could have been used by
clients of utils::directories class to provide dirs for creation.
Due to moving the responsibility for providing paths of dirs from
db::config to utils::directories, such usage is no longer the case.
This change:
- defines utils::directories::set in utils/directories.cc to disallow
its usage by the clients of utils::directories
- makes utils::directories::create_and_verify() member function
private; now it is used only by the internals of the class
- introduces a new member function to utils::directories called
create_and_verify_sharded_directory() to limit the functionality
provided to clients
Signed-off-by: Patryk Wrobel <patryk.wrobel@scylladb.com>
In this commit, we postpone the start-up
of the hint manager until we obtain information
about other nodes in the cluster.
When we start the hint managers, one of the
things that happen is creating endpoint
managers -- structures managed by
db::hints::manager. Whether we create
an instance of endpoint manager depends on
the value returned by host_filter::can_hint_for,
which, in turn, may depend on the current state
of locator::topology.
If locator::topology is incomplete, some endpoint
managers may not be started even though they
should (because the target node IS part of the
cluster and we SHOULD send hints to it if there
are some).
The situation like that can happen because we
start the hint managers too early. This commit
aims to solve that problem. We only start
the hint managers when we've gathered information
about the other nodes in the cluster and created
the locator::topology using it.
Hinted Handoff is not negatively affected by these
changes since in between the previous point of
starting the hint managers and the current one,
all of the mutations performed by
service::storage_proxy target the local node, so
no hints would need to be generated anyway.
Fixesscylladb/scylladb#11870Closesscylladb/scylladb#16511
database::get_token_metadata() is switched to token_metadata2.
get_all_ips method is added to the host_id-based token_metadata, since
its convenient and will be used in several places. It returns all current
nodes converted to inet_address by means of the topology
contained within token_metadata.
hint_sender::can_send: if the node has already left the
cluster we may not find its host_id. This case is handled
in the same way as if it's not a normal token owner - we
simply send a hint to all replicas.
Fixes some more typos as found by codespell run on the code. In this commit, there are more user-visible errors.
Refs: https://github.com/scylladb/scylladb/issues/16255Closesscylladb/scylladb#16289
* github.com:scylladb/scylladb:
Update unified/build_unified.sh
Update main.cc
Update dist/common/scripts/scylla-housekeeping
Typos: fix typos in code
Fixes some typos as found by codespell run on the code.
In this commit, I was hoping to fix only comments, not user-visible alerts, output, etc.
Follow-up commits will take care of them.
Refs: https://github.com/scylladb/scylladb/issues/16255
Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>
the operator<<() based formatter is only used in its test, so
let's move it to where it is used.
we can always bring it back later if it is required in other places.
but better off implementing it as a fmt::formatter<> then.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16142
The current comments should be clearer to someone
not familiar with the module. This commit also makes
them abide by the limit of 120 characters per line.
space_watchdog is a friend of shard hint manager just to
be able to execute one of its functions. This commit changes
that by unfriending the class and exposing the function.
