In preparation for intra-node tablet migration, to avoid
using deprecated sharder APIs.
This function is used for generating sstable sharding metadata.
For tablets, it is not invoked, so we can safely work with the
static sharder. The call site already passes static_sharder only.
In preparation for tablet intra-node migration.
Existing uses are for reads, so it's safe to use shard_for_reads():
- in multishard reader
- in forward_service
The ring_position_range_vector_sharder is used when computing sstable
shards, which for intra-node migration should use the view for
reads. If we haven't completed streaming, sstables should be attached
to the old shard (used by reads). When in write-both-read-new stage,
streaming is complete, reads are using the new shard, and we should
attach sstables to the new shard.
When not in intra-node migration, the view for reads on the pending
node will return the pending shard even if read selector is "read old".
So if pending node restarts during streaming, we will attach to sstables
to the shard which is used by writes even though we're using the selector
for reads.
I analyzed all the uses and all except the alternator/ttl.cc seem to
be interested in the result for the purpose of reading.
Alternator is not supported with tablets yet, so the use was annotated
with a relevant issue.
Before the patch, dht::sharder could be instantiated and it would
behave like a static sharder. This is not safe with regards to
extensions of the API because if a derived implementation forgets to
override some method, it would incorrectly default to the
implementation from static sharder. Better to fail the compilation in
this case, so extract static sharder logic to dht::static_sharder
class and make all methods in dht::sharder pure virtual.
This also allows us to have algorithms indicate that they only work
with static sharder by accepting the type, and have compile-time
safety for this requirement.
schema::get_sharder() is changed to return the static_sharder&.
Require users to specify whether we want shard for reads or for writes
by switching to appropriate non-deprecated variant.
For example, shard_of() can be replaced with shard_for_reads() or
shard_for_writes().
The next_shard/token_for_next_shard APIs have only for-reads variant,
and the act of switching will be a testimony to the fact that the code
is valid for intra-node migration.
During streaming for intra-node migration we want to write only to the
new shard. To achieve that, allow altering write selector in
sharder::shard_for_writes() and per-instance of
auto_refreshing_sharder.
Tablet sharder is adjusted to handle intra-migration where a tablet
can have two replicas on the same host. For reads, sharder uses the
read selector to resolve the conflict. For writes, the write selector
is used.
The old shard_of() API is kept to represent shard for reads, and new
method is introduced to query the shards for writing:
shard_for_writes(). All writers should be switched to that API, which
is not done in this patch yet.
The request handler on replica side acts as a second-level
coordinator, using sharder to determine routing to shards. A given
sharder has a scope of a single topology version, a single
effective_replication_map_ptr, which should be kept alive during
writes.
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
Our interval template started life as `range`, and was supported
wrapping to follow Cassandra's convention of wrapping around the
maximum token.
We later recognized that an interval type should usually be non-wrapping
and split it into wrapping_range and nonwrapping_range, with `range`
aliasing wrapping_range to preserve compatibility.
Even later, we realized the name was already taken by C++ ranges and
so renamed it to `interval`. Given that intervals are usually non-wrapping,
the default `interval` type is non-wrapping.
We can now simplify it further, recognizing that everyone assumes
that an interval is non-wrapping and so doesn't need the
nonwrapping_interval_designation. We just rename nonwrapping_interval
to `interval` and remove the type alias.
Consider the inclusiveness of the token-range's start and end bounds and
copy the flag to the output bounds, instead of assuming they are always
inclusive.
range.hh was deprecated in bd794629f9 (2020) since its names
conflict with the C++ library concept of an iterator range. The name
::range also mapped to the dangerous wrapping_interval rather than
nonwrapping_interval.
Complete the deprecation by removing range.hh and replacing all the
aliases by the names they point to from the interval library. Note
this now exposes uses of wrapping intervals as they are now explicit.
The unit tests are renamed and range.hh is deleted.
Closesscylladb/scylladb#17428
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
`partition_range_view` and `i_partition`, and drop their operator<<:s.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17331
This commit renames keyspace::get_effective_replication_map()
to keyspace::get_vnode_effective_replication_map(). This change
is required to ease the analysis of the usage of this function.
When tablets are enabled, then this function shall not be used.
Instead of per-keyspace, per-table replication map should be used.
The rename was performed to distinguish between those two calls.
The next step will be an audit of usages of
keyspace::get_vnode_effective_replication_map().
Refs: scylladb#16626
Signed-off-by: Patryk Wrobel <patryk.wrobel@scylladb.com>
Closesscylladb/scylladb#17314
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 `dht::ring_posittion`,
and drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17194
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 `dht::sharder`, and drop
its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17178
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 `dht::ring_position_ext` and
`dht::ring_position_view`, and drop their operator<<.
Refs #13245Closesscylladb/scylladb#17128
* github.com:scylladb/scylladb:
db: add formatter for dht::ring_position_ext
db: add formatter for dht::ring_position_view
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.
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 `dht::ring_position_ext`,
and drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
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 `dht::ring_position_view`,
and drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
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 dht::decorated_key and
repair_sync_boundary.
please note, before this change, repair_sync_boundary was using
the operator<< based formatter of `dht::decorated_key`, so we are
updating both of them in a single commit.
because we still use the homebrew generic formatter of vector<>
in to format vector<repair_sync_boundary> and vector<dht::decorated_key>,
so their operator<< are preserved.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16994
This patch reverts commit 10f8f13b90 from
November 2022. That commit added to the "view update generator", the code
which builds view updates for staging sstables, a filter that ignores
ranges that do not belong to this node. However,
1. I believe this filter was never necessary, because the view update
code already silently ignores base updates which do not belong to
this replica (see get_view_natural_endpoint()). After all, the view
update needs to know that this replica is the Nth owner of the base
update to send its update to the Nth view replica, but if no such
N exists, no view update is sent.
2. The code introduced for that filter used a per-keyspace replication
map, which was ok for vnodes but no longer works for tablets, and
causes the operation using it to fail.
3. The filter was used every time the "view update generator" was used,
regardless of whether any cleanup is necessary or not, so every
such operation would fail with tablets. So for example the dtest
test_mvs_populating_from_existing_data fails with tablets:
* This test has view building in parallel with automatic tablet
movement.
* Tablet movement is streaming.
* When streaming happens before view building has finished, the
streamed sstables get "view update generator" run on them.
This causes the problematic code to be called.
Before this patch, the dtest test_mvs_populating_from_existing_data
fails when tablets are enabled. After this patch, it passes.
Fixes#16598
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Change the token_metadata type to token_metadata2 in
the signatures of CDC-related methods in
storage_service and cdc/generation. Use
get_new_strong to get a pointer to the new host_id-based
token_metadata from the inet_address-based one,
living in the shared_token_metadata.
The starting point of the patch is in
storage_service::handle_global_request. We change the
tmptr type to token_metadata2 and propagate the change
down the call chains. This includes token-related methods
of the boot_strapper class.
Tablet streaming involves asynchronous RPCs to other replicas which transfer writes. We want side-effects from streaming only within the migration stage in which the streaming was started. This is currently not guaranteed on failure. When streaming master fails (e.g. due to RPC failing), it can be that some streaming work is still alive somewhere (e.g. RPC on wire) and will have side-effects at some point later.
This PR implements tracking of all operations involved in streaming which may have side-effects, which allows the topology change coordinator to fence them and wait for them to complete if they were already admitted.
The tracking and fencing is implemented by using global "sessions", created for streaming of a single tablet. Session is globally identified by UUID. The identifier is assigned by the topology change coordinator, and stored in system.tablets. Sessions are created and closed based on group0 state (tablet metadata) by the barrier command sent to each replica, which we already do on transitions between stages. Also, each barrier waits for sessions which have been closed to be drained.
The barrier is blocked only if there is some session with work which was left behind by unsuccessful streaming. In which case it should not be blocked for long, because streaming process checks often if the guard was left behind and stops if it was.
This mechanism of tracking is fault-tolerant: session id is stored in group0, so coordinator can make progress on failover. The barriers guarantee that session exists on all replicas, and that it will be closed on all replicas.
Closesscylladb/scylladb#15847
* github.com:scylladb/scylladb:
test: tablets: Add test for failed streaming being fenced away
error_injection: Introduce poll_for_message()
error_injection: Make is_enabled() public
api: Add API to kill connection to a particular host
range_streamer: Do not block topology change barriers around streaming
range_streamer, tablets: Do not keep token metadata around streaming
tablets: Fail gracefully when migrating tablet has no pending replica
storage_service, api: Add API to disable tablet balancing
storage_service, api: Add API to migrate a tablet
storage_service, raft topology: Run streaming under session topology guard
storage_service, tablets: Use session to guard tablet streaming
tablets: Add per-tablet session id field to tablet metadata
service: range_streamer: Propagate topology_guard to receivers
streaming: Always close the rpc::sink
storage_service: Introduce concept of a topology_guard
storage_service: Introduce session concept
tablets: Fix topology_metadata_guard holding on to the old erm
docs: Document the topology_guard mechanism
Streaming was keeping effective_replication_map_ptr around the whole
process, which blocks topology change barriers.
This will inhibit progress of tablet load balancer or concurrent
migrations, resulting in worse performance.
Fix by switching to the most recent erm on sharder
calls. multishard_writer calls shard_of() for each new partition.
A better way would be to switch immediately when topology version
changes, but this is left for later.
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>
to have feature parity with `configure.py`. we won't need this
once we migrate to C++20 modules. but before that day comes, we
need to stick with C++ headers.
we generate a rule for each .hh files to create a corresponding
.cc and then compile it, in order to verify the self-containness of
that header. so the number of rule is quite large, to avoid the
unnecessary overhead. the check-header target is enabled only if
`Scylla_CHECK_HEADERS` option is enabled.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#15913
Extract decorated_key.hh and ring_position.hh
out of i_partitioner.hh so they can be included
selectively, since i_partitioner.hh contains too much
bagage that is not always needed in full.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the `token_comparator` definition and
implementation to token.{hh,cc}, respectively
since they are independent of i_partitioner.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This option allows user to change the number of ranges to stream in
batch per stream plan.
Currently, each stream plan streams 10% of the total ranges.
With more ranges per stream plan, it reduces the waiting time between
two stream plans. For example,
stream_plan1: shard0 (t0), shard1 (t1)
stream_plan2: shard0 (t2), shard1 (t3)
We start stream_plan2 after all shards finish streaming in stream_plan1.
If shard0 and shard1 in stream_plan1 finishes at different time. One of
the shards will be idle.
If we stream more ranges in a single stream plan, the waiting time will
be reduced.
Previously, we retry the stream plan if one of the stream plans is
failed. That's one of the reasons we want more stream plans. With RBNO
and 1f8b529e08 (range_streamer: Disable restream logic), the
restream factor is not important anymore.
Also, more ranges in a single stream plan will create bigger but fewer
sstables on the receiver side.
The default value is the same as before: 10% percentage of total ranges.
Fixes#14191Closes#14402
Today, SSTable cleanup skips to the next partition, one at a time, when it finds
that the current partition is no longer owned by this node.
That's very inefficient because when a cluster is growing in size, existing
nodes lose multiple sequential tokens in its owned ranges. Another inefficiency
comes from fetching index pages spanning all unowned tokens, which was described
in #14317.
To solve both problems, cleanup will now use multi range reader, to guarantee
that it will only process the owned data and as a result skip unowned data.
This results in cleanup scanning an owned range and then fast forwarding to the
next one, until it's done with them all. This reduces significantly the amount
of data in the index caching, as index will only be invoked at each range
boundary instead.
Without further ado,
before:
... 2GB to 1GB (~50% of original) in 26248ms = 81MB/s. ~9443072 total partitions merged to 4750028.
after:
... 2GB to 1GB (~50% of original) in 17424ms = 123MB/s. ~9443072 total partitions merged to 4750028.
Fixes#12998.
Fixes#14317.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
This is in order to prevent new incorrect uses of dht::shard_of() to
be accidentally added. Also, makes sure that all current uses are
caught by the compiler and require an explicit rename.
Currently, the coordinator splits the partition range at vnode (or
tablet) boundaries and then tries to merge adjacent ranges which
target the same replica. This is an optimization which makes less
sense with tablets, which are supposed to be of substantial size. If
we don't merge the ranges, then with tablets we can avoid using the
multishard reader on the replica side, since each tablet lives on a
single shard.
The main reason to avoid a multishard reader is avoiding its
complexity, and avoiding adapting it to work with tablet
sharding. Currently, the multishard reader implementation makes
several assumptions about shard assignment which do not hold with
tablets. It assumes that shards are assigned in a round-robin fashion.
