The "tags" mechanism in Alternator is a convenient way to attach metadata
to Alternator tables. Recently we have started using it more and more for
internal metadata storage:
* UpdateTimeToLive stores the attribute in a tag system:ttl_attribute
* CreateTable stores provisioned throughput in tags
system:provisioned_rcu and system:provisioned_wcu
* CreateTable stores the table's creation time in a tag called
system:table_creation_time.
We do not want any of these internal tags to be visible to a
ListTagsOfResource request, because if they are visible (as before this
patch), systems such as Terraform can get confused when they suddenly
see a tag which they didn't set - and may even attempt to delete it
(as reported in issue #24098).
Moreover, we don't want any of these internal tags to be writable
with TagResource or UntagResource: If a user wants to change the TTL
setting they should do it via UpdateTimeToLive - not by writing
directly to tags.
So in this patch we forbid read or write to *any* tag that begins
with the "system:" prefix, except one: "system:write_isolation".
That tag is deliberately intended to be writable by the user, as
a configuration mechanism, and is never created internally by
Scylla. We should have perhaps chosen a different prefix for
configurable vs. internal tags, or chosen more unique prefixes -
but let's not change these historic names now.
This patch also adds regression tests for the internal tags features,
failing before this patch and passing after:
1. internal tags, specifically system:ttl_attribute, are not visible
in ListTagsOfResource, and cannot be modified by TagResource or
UntagResource.
2. system:write_isolation is not internal, and be written by either
TagResource or UntagResource, and read with ListTagsOfResource.
This patch also fixes a bug in the test where we added more checks
for system:write_isolation - test_tag_resource_write_isolation_values.
This test forgot to remove the system:write_isolation tags from
test_table when it ended, which would lead to other tests that run
later to run with a non-default write isolation - something which we
never intended.
Fixes#24098.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#24299
(cherry picked from commit 6cbcabd100)
Closesscylladb/scylladb#24377
This series adds support for WCU tracking in batch_write_item and tests it.
The patches include:
Switch the metrics (RCU and WCU) to count units vs half-units as they were, to make the metrics clearer for users.
Adding a public static get_half_units function to wcu_consumed_capacity_counter for use by batch write item, which cannot directly use the counter object.
Adding WCU calculation support to batch_write_item, based on item size for puts and a fixed 1 WCU for deletes. WCU metrics are updated, and consumed capacity is returned per table when requested.
The return handling was refactored to be coroutine-like for easier management of the consumed capacity array.
Adding tests that validate WCU calculation for batch put requests on a single table and across multiple tables, ensuring delete operations are counted correctly.
Adding a test that validates that WCU metrics are updated correctly during batch write item operations, ensuring the WCU of each item is calculated independently.
**Need backport, WCU is partially supported, and is missing from batch_write_item**
Fixes#23940Closesscylladb/scylladb#23941
* github.com:scylladb/scylladb:
alternator/test_metrics.py: batch_write validate WCU
alternator/test_returnconsumedcapacity.py: Add tests for batch write WCU
alternator/executor: add WCU for batch_write_items
alternator/consumed_capacity: make wcu get_units public
Alternator: Change the WCU/RCU to use units
This patch adds consumed capacity unit support to batch_write_item.
It calculates the WCU based on an item's length (for put) or a static 1
WCU (for delete), for each item on each table.
The WCU metrics are always updated. if the user requests consumed
capacity, a vector of consumed capacity is returned with an entry for
each of the tables.
For code simplicity, the return part of batch_write_item was updated to
be coroutine-like; this makes it easier to manage the life cycle of the
returned consumed_capacity array.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
This patch adds a public static get_units function to
wcu_consumed_capacity_counter. It will be used by the batch write item
implementation, which cannot use the wcu_consumed_capacity_counter
directly.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
consume_capacity need merge
This patch changes the RCU/WCU Alternator metrics to use whole units
instead of half units. The change includes the following:
Change the metrics documentation. Keep the RCU counter internally in
half units, but return the actual (whole unit) value.
Change the RCU name to be rcu_half_units_total to indicates that it
counts half units.
Change the WCU to count in whole units instead of half units.
Update the tests accordingly.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
In ScyllaDB, schema modification operations use "optimistic locking":
A schema operation reads the current schema, decides what it wants to do
and prepares changes to the schema, and then attempts to commit those
changes - but only if the schema hasn't changed since the first read.
If the schema has already been changed by some other node - we need to
try again. In a loop.
In Alternator, there are six operations that perform schema modification:
CreateTable, DeleteTable, UpdateTable, TagResource, UntagResource and
UpdateTimeToLive. All of them were missing this loop. We knew about
this - and even had FIXME in all places. So all these operations,
when facing contention of concurrent schema modifications on different
nodes may fail one of these operations with an error like:
Internal server error: service::group0_concurrent_modification
(Failed to apply group 0 change due to concurrent modification).
This problem had very minor effect, if any, on real users because the
DynamoDB SDK automatically retries operations that fail with retryable
errors - like this "Internal server error" - and most likely the schema
operation will succeed upon retry. However, as shown in issue #13152
these failures were annoying in our CI, where tests - which disable
request retries - failed on these errors.
This patch fixes all six operations (the last three operations all
use one common function, db::modify_tags(), so are fixed by one
change) to add the missing loop.
The patch also includes reproducing tests for all these operations -
the new tests all fail before this patch, and pass with it.
These new tests are much more reliable reproducers than the dtests
we had that only sometimes - very rarely - reproduced the problem.
Moreover, the new tests reproduces the bug seperately for each of the
six operations, so if we forget to fix one of the six operations, one
of the tests would have continued to fail. Of course I checked this
during development.
The new tests are in the test/cluster framework, not test/alternator,
because this problem can only be reproduced in a multi-node cluster:
On a single node, it serializes its schema modifications on its own;
The collisions only happen when more than one node attempts schema
modifications at the same time.
Fixes#13152
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#23827
Currently, the base_info may or may not be set in view schemas.
Even when it's set, it may be modified. This necessitates extra
checks when handling view schemas, as we'll as potentially causing
errors when we forget to set it at some point.
Instead, we want to make the base info an immutable member of view
schemas (inside view_info). To achieve this, in this series we remove
all base_info members that can change due to a base schema update,
and we calculate the remaining values during view update generation,
using the most up-to-date base schema version.
To calculate the values that depend on the base schema version, we
need to iterate over the view primary key and find the corresponding
columns, which adds extra overhead for each batch of view updates.
However, this overhead should be relatively small, as when creating
a view update, we need to prepare each of its columns anyway. And
if we need to read the old value of the base row, the relative
overhead is even lower.
After this change, the base info in view schemas stays the same
for all base schema updates, so we'll no longer get issues with
base_info being incompatible with a base schema version. Additionally,
it's a step towards making the schema objects immutable, which
we sometimes incorrectly assumed in the past (they're still not
completely immutable yet, as some other fields in view_info other
than base_info are initialized lazily and may depend on the base
schema version).
Fixes https://github.com/scylladb/scylladb/issues/9059
Fixes https://github.com/scylladb/scylladb/issues/21292
Fixes https://github.com/scylladb/scylladb/issues/22194
Fixes https://github.com/scylladb/scylladb/issues/22410Closesscylladb/scylladb#23337
* github.com:scylladb/scylladb:
test: remove flakiness from test_schema_is_recovered_after_dying
mv: add a test for dropping an index while it's building
base_info: remove the lw_shared_ptr variant
view_info: don't re-set base_info after construction
base_info: remove base_info snapshot semantics
base_info: remove base schema from the base_info
schema_registry: store base info instead of base schema for view entries
base_info: make members non-const
view_info: move the base info to a separate header
view_info: move computation of view pk columns not in base pk to view_updates
view_info: move base-dependent variables into base_info
view_info: set base info on construction
Attribute names are now checked against DynamoDB-compatible length
limits. When exceeded, Alternator emits exception identical or similar
to the DDB one. It might be worth noting that DDB emits more than a
single kind of an exception string for some exceptions. The tests'
catch clauses handle all the observed kinds of messages from DynamoDB.
The validation differentiates between key and non-key attributes and
applies the limit accordingly.
AWS DDB raises exceptions with somewhat different contents when the
get request contains ProjectionExpression, so this case needed separate
treatment to emit the corresponding exception string. The
length-validating function was declared and defined in
expressions.hh/.cc respectively, because that's where the relevant
parsing happens.
** Tests
The following tests were validated when handling this issue:
test_limit_attribute_length_nonkey_good,
test_limit_attribute_length_nonkey_bad,
test_limit_attribute_length_key_good,
test_limit_attribute_length_key_bad,
test_limit_attribute_length_gsi_lsi_good,
test_limit_attribute_length_gsi_lsi_bad,
test_limit_attribute_length_gsi_lsi_projection_bad.
Some of the tests were expanded into being more granular. Namely, there
is a new test function
`test_limit_attribute_length_key_bad_incoherent_names`
which groups tests with too long attribute names in the case of
incorrect (incoherent) user requests.
Similarily, there is a new test function
`test_limit_attribute_length_gsi_lsi_bad_incoherent_names`
All the tests cover now each combination of the key/keys being too long.
Both the new fuctions contain tests that verify that ScyllaDB throws
length-related exceptions (instead of the coherency-related), similar
to what DynamoDB does.
The new test test_limit_gsiu_key_len_bad covers the case of too long
attribute name inside GlobalSecondaryIndexUpdates.
The new test test_limit_gsiu_key_len_bad_incoherent_names covers the
case of incorrect (incoherent) user requests containing too long
attribute names and GlobalSecondaryIndexUpdates.
test_limit_attribute_length_key_bad was found to have contaned an
illegal KeySchema structure.
Some of the tests were corrected their match clause.
All the tests are stripped of the xfail flag except
test_limit_attribute_length_key_bad, which has it changed since it
still fails due to Projection in GSI and LIS not implemented in Alternator.
The xfail now points to #5036.
Fixesscylladb/scylladb#9169Closesscylladb/scylladb#23097
Currently, the base_info may or may not be set in view schemas.
Even when it's set, it may be modified. This necessitates extra
checks when handling view schemas, as well as potentially causing
errors when we forget to set it at some point.
Instead, we want to make the base info an immutable member of view
schemas (inside view_info). The first step towards that is making
sure that all newly created schemas have the base info set.
We achieve that by requiring a base schema when constructing a view
schema. Unfortunately, this adds complexity each time we're making
a view schema - we need to get the base schema as well.
In most cases, the base schema is already available. The most
problematic scenario is when we create a schema from mutations:
- when parsing system tables we can get the schema from the
database, as regular tables are parsed before views
- when loading a view schema using the schema loader tool, we need
to load the base additionally to the view schema, effectively
doubling the work
- when pulling the schema from another node - in this case we can
only get the current version of the base schema from the local
database
Additionally, we need to consider the base schema version - when
we generate view updates the version of the base schema used for
reads should match the version of the base schema in view's base
info.
This is achieved by selecting the correct (old or new) schema in
`db::schema_tables::merge_tables_and_views` and using the stored
base schema in the schema_registry.
This series adds support for reporting consumed capacity in BatchGetItem operations in Alternator.
It includes changes to the RCU accounting logic, exposing internal functionality to support batch-specific behavior, and adds corresponding tests for both simple and complex use cases involving multiple tables and consistency modes.
Need backporting to 2025.1, as RCU and WCU are not fully supported
Fixes#23690Closesscylladb/scylladb#23691
* github.com:scylladb/scylladb:
test_returnconsumedcapacity.py: test RCU for batch get item
alternator/executor: Add RCU support for batch get items
alternator/consumed_capacity: make functionality public
This patch adds RCU support for batch get items. With batch requests,
multiple objects are read from multiple tables. While the criterion for
adding the units is per the batch request, the units are calculated per
table—and so is the read consistency.
The consumed_capacity_counter is not completely applicable for batch
operations. This patch makes some of its functionality public so that
batch get item can use the components to decide if it needs to send
consumed capacity in the reply, to get the half units used by the
metrics and returned result, and to allow an empty constructor for the
RCU counter.
This series adds a histogram for get and write batch sizes.
It uses the estimated_histogram implementation which starts from 1 with 1.2 exponential factor, which works
extremely tight to 20 but still covers all the way to 100.
Histograms will be reported per node.
**Backport to 2025.1 so we'll have information about user batch size limitation**
Closesscylladb/scylladb#23379
* github.com:scylladb/scylladb:
alternator: Add tests for the batch items histograms
alternator: Add histogram for batch item count
Alternator Streams' "GetRecords" operation has a "Limit" parameter on
how many records to return. The DynamoDB documentations says that the
upper limit on this Limit parameter is 1000 - but Alternator didn't
enforce this. In this patch we begin enforcing this highest Limit, and
also add a test for verifying this enforcement. As usual, the new test
passes on DynamoDB, and after this patch - also on Alternator.
The reason why it's useful to have *some* upper limit on Limit is that
the existing executor::get_records() implementation does not really have
preemption points in all the necessary places. In particular, we have a
loop on all returned records without preemption points. We also store
the returned records in a RapidJson vector, which requires a contiguous
allocation.
Even before this patch, GetRecords had a hard limit of 1 MB of results.
But still, in some cases 1 MB of results may be a lot of results, and we
can see stalls in the aforementioned places being O(number of results).
Fixes#23534
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#23547
This patch adds an estimated_histogram for alternator batch item count.
estimated_histogram can be used with values starting from 1 with an
exponential factor of 1.2, which nicely covers values up to 20, but with
only 22 buckets it can reach all the way to 100 (plus infinity).
Aside from the new histograms for get and write batches, a helper
function was added to return the histogram in the metric format without
changing its resolution (which is the metric’s default behaviour).
The histogram will be reported once per node rather than once per shard.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
Add a size check for BatchItemWrite command - if the item count is
bigger than configuration value `alternator_maximum_batch_write_size`,
an error will be raised and no modification will happen.
This is done to synchronize with DynamoDB, where maximum size of
BatchItemWrite is 25. To avoid complaints from clients, who use
our feature of BatchWriteItem being limitless we set default value
to 100.
Fixes#5057Closesscylladb/scylladb#23232
This patch changes gossiper to index nodes by host ids instead of ips.
The main data structure that changes is _endpoint_state_map, but this
results in a lot of changes since everything that uses the map directly
or indirectly has to be changed. The big victim of this outside of the
gossiper itself is topology over gossiper code. It works on IPs and
assumes the gossiper does the same and both need to be changed together.
Changes to other subsystems are much smaller since they already mostly
work on host ids anyway.
The following metrics will be marked with basic_level label:
scylla_alternator_operation
scylla_alternator_op_latency_bucket
scylla_alternator_op_latency_count
scylla_alternator_op_latency_sum
scylla_alternator_total_operations
scylla_alternator_batch_item_count
scylla_alternator_op_latency
scylla_alternator_op_latency_summary
scylla_expiration_items_deleted
All alternator metrics are marked with __alternator label.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
If user fails to supply the AttributeDefinitions parameter when creating
a table, Scylla used to fail on RAPIDJSON_ASSERT. Now it calls a polite
exception, which is fully in-line with what DynamoDB does.
The commit supplies also a new, relevant test routine.
Fixes#23043Closesscylladb/scylladb#23041
This commit eliminates unused boost header includes from the tree.
Removing these unnecessary includes reduces dependencies on the
external Boost.Adapters library, leading to faster compile times
and a slightly cleaner codebase.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22997
Table updates that try to enable stream (while changing or not the
StreamViewType) on a table that already has the stream enabled
will result in ValidationError.
Table updates that try to disable stream on a table that does not
have the stream enabled will result in ValidationError.
Add two tests to verify the above.
Mark the test for changing the existing stream's StreamViewType
not to xfail.
Fixesscylladb/scylladb#6939Closesscylladb/scylladb#22827
The main goal of this patch is to fully support UpdateTable's ability
to add a GSI to an existing table, and delete a GSI from an existing
table. But to achieve this, this patch first needs to overhaul how GSIs
are implemented:
Remember that in Alternator's data model, key attributes in a table
are stored as real CQL columns (with a known type), but all other
attributes of an item are stored in one map called ":attrs".
* Before this patch, the GSI's key columns were made into real columns
in the table's schema, and the materialized view used that column as
the view's key.
* After this patch, the GSI's key columns usually (when they are not
the base table's keys, and not any LSI's key) are left in the ":attrs"
map, just like any other non-key column. We use a new type of computed
column (added in the previous patch) to extract the desired element from
this map.
This overhaul of the GSI implementation doesn't change anything in the
functionality of GSIs (and the Alternator test suite tries very hard to
ensure that), but finally allows us to add a GSI to an already-existing
table. This is now possible because the GSI will be able to pick up
existing data from inside the ":attrs" map where it is stored, instead
of requiring the data in the map to be moved to a stand-alone column as
the previous implementation needed.
So this patch also finally implements the UpdateTable operations
(Create and Delete) to add or delete a GSI on an existing table,
as this is now fairly straightfoward. For the process of "backfilling"
the existing data into the new GSI we don't need to do anything - this
is just the materialized-view "view building" process that already
exists.
Fixes#11567.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds a new computed column class for materialized views,
extract_from_attrs_column_computation
which is Alternator-specific and knows how to extract a value (of a
known type) from an attribute stored in Alternator's map-of-all-nonkey-
attributes ":attrs".
We'll use this new computed column in the next patch to reimplement GSI.
The new computed-column class is based on regular_column_transformation
introduced in the previous patch. It is not yet wired to anything:
The MV code cannot handle any regular_column_transformation yet, and
Alternator will not yet use it to create a GSI. We'll do those things
in the following patches.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch introduces a function serialized_value_if_type() which takes
a serialized value stored in the ":attrs" map, and converts it into a
serialized *CQL* type if it matches a particular type (S, B or N) - or
returns null the value has the wrong type.
We will use this function in the following patch for deserializing
values stored in the ":attrs" map to use them as a materialized view
key. If the value has the right type, it will be converted to the CQL
type and used as the key - but if it has the wrong type the key will
be null and it will not appear in the view. This is exactly how GSI
is supposed to behave.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds the missing IndexStatus and Backfilling fields for the
GSIs listed by a DescribeTable request. These fields allow an application
to check whether a GSI has been fully built (IndexStatus=ACTIVE) or
currently being built (IndexStatus=CREATING, Backfilling=true).
This feature is necessary when a GSI can be added to an existing table
so its backfilling might take time - and the application might want to
wait for it.
One test - test_gsi.py::test_gsi_describe_indexstatus - begins to pass
with this fix, so the xfail tag is removed from it.
Fixes#11471.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds to Alternator's api_error type yet another type of
error, api_error::limit_exceeded (error code "LimitExceededException").
DynamoDB returns this error code in certain situations where certain
low limits were exceeded, such as the case we'll need in a following
patch - an UpdateTable that tries to create more than one GSI at once.
The LimitExceededException error type should not be confused with
other similarly-named but different error messages like
ProvisionedThroughputExceededException or RequestLimitExceeded.
In general, we make an attempt to return the same error code that
DynamoDB returns for a given error.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
these unused includes were identifier by clang-include-cleaner. after
auditing these source files, all of the reports have been confirmed.
please note, because quite a few source files relied on
`utils/to_string.hh` to pull in the specialization of
`fmt::formatter<std::optional<T>>`, after removing
`#include <fmt/std.h>` from `utils/to_string.hh`, we have to
include `fmt/std.h` directly.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
This series adds WCU support for the Alternator update item.
This motivation behind it, is to have a rough estimation of what a similar operation would have taken from WCU perspective if used with DynamoDB.
The calculation is done while minimal overhead is the prime objective, the results are values that is less or equal to what it would have been in DynamoDB
** New feature, no need to backport. **
Closesscylladb/scylladb#21999
* github.com:scylladb/scylladb:
alternator/test_returnconsumedcapacity.py: update item
alternator/executor.cc: Add WCU for update_item
Currently, `get_network_topology_options()` is using gossip data
and iterates over topology using IPs and not host IDs, which may
result in operating on inconsistent data.
This method's implemenations has been changed to instead use
`get_datacenters()`, which should always return consistent data.
Fixes: scylladb/scylladb#21490Closesscylladb/scylladb#21940
This patch adds WCU support for update_item. The way Alternator modifies
values means we don't always have the full item sizes. When there is a
read-before-write, the code in rmw_operation takes care of the object
size.
When updating a value without read-before-write, we will make a rough
estimation of the value's size. This is better than simply taking 1 (as
we do with delete) and is also more Alternator-like.
Clean up the unnecessary includes reported by the GitHub checks that are
polluting the PR diffs.
The "utils/assert.hh" report should be actually fixed by the #21739, but
as the usage of `SEASTAR_ASSERT()` is protected by the `SEASTAR_DEBUG`
check it makes sense to include the header conditionally as well.
Closesscylladb/scylladb#21817
Calculating the item length of WCU deleted Item depends on how the
operations was performed.
In a simple scenario it would be consider a 1 byte.
With an unsafe Read-Before-Write the item is return by get_perious_item
and with LWT the item is get from the apply method.
This patch changes the calls to describe_single_item in the last two
scenarios so that they would use the read item to determine the item
length.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
Actions in rmw_operation can use describe_item to determine to get an
existing value (Read before Write scenario) on those cases the existing
item size can be bigger than the one we are storing (in the extreme
case, when deleting an object we only have its keys)
This modify the describe_item API so it would take a pointer to uint
instead of the consumed_capacity_counter so we can use it to get the old
value size and depends on that, determine the size that will be used for
the WCU calculation.
rmw operations needs to be able to modify consume_capacity total_bytes
directly.
Depends on the previous stored item the length on which the WCU will be
calculated can be different than the length of the operation.
This patch makes the total_bytes public so it will be possible to modify
it directly.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
This patch add visibility to the WCU metrics. It uses a label 'ops' to
split each of the operations that contribute to WCU into their
operations.
When summing over all ops value the result will be the same.
these unused includes are identified by clang-include-cleaner. after
auditing the source files, all of the reports have been confirmed.
please note, because `mutation/mutation.hh` does not include
`seastar/coroutine/maybe_yield.hh` anymore, and quite a few source
files were relying on this header to bring in the declaration of
`maybe_yield()`, we have to include this header in the places where
this symbol is used. the same applies to `seastar/core/when_all.hh`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
This change improves dependency management by explicitly specifying
library linkage visibility in CMake targets.
Previously, some ScyllaDB targets used `target_link_libraries()`
without `PUBLIC` or `PRIVATE` keywords, which resulted in transitive
library dependencies by default. This unintentionally exposed
non-public dependencies to downstream targets.
Changes:
- Always use explicit `PRIVATE` or `PUBLIC` keywords with
`target_link_libraries()`
- Tighten build dependency tree
- Enforce a more modular linkage model
See: [CMake documentation on library dependencies](https://cmake.org/cmake/help/latest/command/target_link_libraries.html)
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21686
Modernize the codebase by replacing Boost range adaptors with C++23 standard library views,
reducing external dependencies and leveraging modern C++ language features.
Key Changes:
- Replace `boost::adaptors::filtered` with `std::views::filter`
- Remove `#include <boost/range/adaptor/filtered.hpp>`
- Utilize standard library range views
Motivation:
- Reduce project's external dependency footprint
- Leverage standard library's range and view capabilities
- Improve long-term code maintainability
- Align with modern C++ best practices
Implementation Challenges and Considerations:
1. Range Conversion and Move Semantics
- `std::ranges::to` adaptor requires rvalue references
- Necessitated updates to variable and parameter constness
- Example: `cql3/restrictions/statement_restrictions.cc` modified to remove `const`
from `common` to enable efficient range conversion
2. Range Iteration and Mutation
- Range views may mutate internal state during iteration
- Cannot pass ranges by const reference in some scenarios
- Solution: Pass ranges by rvalue reference to explicitly indicate
state invalidation
Limitations:
- One instance of `boost::adaptors::filtered` temporarily preserved
due to lack of a C++23 alternative for `boost::join()`
- A comprehensive replacement will be addressed in a follow-up change
This change is part of our ongoing effort to modernize the codebase,
reducing external dependencies and adopting modern C++ practices.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21648
Read and Write Consumed Capacity units are an abstract way of measuring Alternator actions. In general, they correspond to the read or write data.
In the long run, the RCU/WCU adds a way of charging an operation and limiting usage.
This series addresses two issues: consume capacity request API and metering.
The Alternator (and DynmoDB) API has an optional parameter allowing users to check the number of units an operation consumes. When a user adds that parameter, the response will contain the number of units used for the operation.
This series adds the consume capacity support to the get_item and put_item, adds a metric to collect the overall RCU and WCU used, and adds a test for the new functionality.
Follow-up PRs will add support for more operations and GSI.
Replaces #19811
Partially implement: #5027Closesscylladb/scylladb#21543
* github.com:scylladb/scylladb:
alternator/test_metrics: Add tests for table consumption units
test_returnconsumedcapacity.py: Add putItem tests
Alternator: add WCU support
Add test/alternator/test_returnconsumedcapacity.py
alternator/executor: Add consume capacity for get_item
alsternator/stats: Add rcu and wcu metrics to stats
alternator/executor.hh: white-space cleanup
Add the consume_capacity helper class
now that we are allowed to use C++23. we now have the luxury of using `std::ranges::find_if`.
in this change, we:
- replace `boost::find_if` with `std::ranges::find_if`
- remove all `#include <boost/range/algorithm/find_if.hpp>`
to reduce the dependency to boost for better maintainability, and leverage standard library features for better long-term support.
this change is part of our ongoing effort to modernize our codebase and reduce external dependencies where possible.
---
it's a cleanup, hence no need to backport.
Closesscylladb/scylladb#21495
* github.com:scylladb/scylladb:
treewide: replace boost::find_if with std::ranges::find_if
counters: replace boost::find_if with std::ranges::find_if
combine.hh: use std::iter_const_reference_t when appropriate
This patch adds functionality to track Write Capacity Units (WCU).
Currently for the put_item operation.
This enhancement allows for standardized measurement of write
operations, aligning with DynamoDB-like metrics.
Additionally, the WCU value is now optionally included in the response to provide
immediate feedback on the write capacity usage.
The implementation adds a consumed_capacity_counter member to
rmw_operation, this will allow to add WCU functionality to update_item
and delete_item
This patch adds functionality to track Read Capacity Units (RCU) for the
get_item operation. This enhancement allows for standardized measurement
of read operations, aligning with DynamoDB-like metrics.
Additionally, the RCU value can now be included in the response to
provide immediate feedback on the read capacity usage.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
