The method `functions::get` is used to get the `functions::function` object
of the CQL function called using `expr::function_call`.
Until now `functions::get` required the caller to pass both the keyspace
and the column family.
The keyspace argument is always needed, as every CQL function belongs
to some keyspace, but the column family isn't used in most cases.
The only case where having the column family is really required
is the `token()` function. Each variant of the `token()` function
belongs to some table, as the arguments to the function are the
consecutive partition key columns.
Let's make the column family argument optional. In most cases
the function will work without information about column family.
In case of the `token()` function there's gonna be a check
and it will throw an exception if the argument is nullopt.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
this is a part of a series to migrating from `operator<<(ostream&, ..)`
based formatting to fmtlib based formatting. the goal here is to enable
fmtlib to print `function_name` without the help of `operator<<`.
the corresponding `operator<<()` are dropped dropped in this change,
as all its callers are now using fmtlib for formatting now.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13608
this change replaces all occurrences of `boost::lexical_cast<std::string>`
in the source tree with `fmt::to_string()`. for couple reasons:
* `boost::lexical_cast<std::string>` is longer than `fmt::to_string()`,
so the latter is easier to parse and read.
* `boost::lexical_cast<std::string>` creates a stringstream under the
hood, so it can use the `operator<<` to stringify the given object.
but stringstream is known to be less performant than fmtlib.
* we are migrating to fmtlib based formatting, see #13245. so
using `fmt::to_string()` helps us to remove yet another dependency
on `operator<<`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13611
Database functions currently receive their arguments as an std::vector. This
is inflexible (for example, one cannot use small_vector to reduce allocations).
This series adapts the function signature to accept parameters using std::span.
Some changes in the keys interface are needed to support this. Lastly, one call
site is migrated to small_vector.
This is in support of changing selectors to use expressions.
Closes#13581
* github.com:scylladb/scylladb:
cql3: abstract_function_selector: use small_vector for argument buffer
db, cql3: functions: pass function parameters as a span instead of a vector
keys: change from_optional_exploded to accept a span instead of a vector
Spans are more flexible and can be constructed from any contiguous
container (such as small_vector), or a subrange of such a container.
This can save allocations, so change the signature to accept a span.
Spans cannot be constructed from std::initializer_list, so one such
call site is changed to use construct a span directly from the single
argument.
When floating-point data contains +Inf and -Inf, the sum is NaN.
Our SUM() aggregation calculated this sum correctly, but then instead
of returning it, complained that the sum overflowed by narrowing.
This was a false positive: The sum() finalizer wanted to test that no
precision was lost when casting the accumulator to the result type,
so checked that the result before and after the cast are the same.
But specifically for NaN, it is never equal to anything - not even
to itself. This check is wrong for floating point, but moreover -
isn't even necessary when the two types (accumulator type and result
type) are identical so in this patch we skip it in this case.
Note that in the current code, a different accumulator and result type
is only used in the case of integer types; When accumulating floating
point sums, the same type is used, so the broken check will be avoided.
The test for this issue starts to pass with this patch, so the xfail
tag is removed.
Fixes#13551
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Currently, aggregate functions are implemented in a statefull manner.
The accumulator is stored internally in an aggregate_function::aggregate,
requiring each query to instantiate new instances (see
aggregate_function_selector's constructor, and note how it's called
from selector::new_instance()).
This makes aggregates hard to use in expressions, since expressions
are stateless (with state only provided to evaluate()). To facilitate
migration towards stateless expressions, we define a
stateless_aggregate_function (modeled after user-defined aggregates,
which are already stateless). This new struct defines the aggregate
in terms of three scalar functions: one to aggregate a new input into
an accumulator (provided in the first parameter), one to finalize an
accumulator into a result, and one to reduce two accumulators for
parallelized aggregation.
All existing native aggregate functions are converted to the new model, and
the old interface is removed. This series does not yet convert selectors to
expressions, but it does remove one of the obstacles.
Performance evaluation: I created a table with a million ints on a single-node cluster, and ran the avg() function on them. I measured the number of instructions executed with `perf stat -p $(pgrep scylla) -e instructions` while the query was running. The query executed from cache, memtables were flushed beforehand. The instruction count per row increased from roughly 49k to roughly 52k, indicating 3k extra instructions per row. While 3k instructions to execute a function is huge, it is currently dwarfed by other overhead (and will be even less important in a cluster where it CL>1 will cause non-coordinator code to run multiple times).
Closes#13105
* github.com:scylladb/scylladb:
cql3/selection, forward_service: use use stateless_aggregate_function directly
db: functions: fold stateless_aggregate_function_adapter into aggregate_function
cql3: functions: simplify accumulator_for template
cql3: functions: base user-defined aggregates on stateless aggregates
cql3: functions: drop native_aggregate_function
cql3: functions: reimplement count(column) statelessly
cql3: functions: reimplement avg() statelessly
cql3: functions: reimplement sum() statelessly
cql3: functions: change wide accumulator type to varint
cql3: functions: unreverse types for min/max
cql3: functions: rename make_{min,max}_dynamic_function
cql3: functions: reimplement min/max statelessly
cql3: functions: reimplement count(*) statelessly
cql3: functions: simplify creating native functions even more
cql3: functions: add helpers for automating marshalling for scalar functions
types: fix big_decimal constructor from literal 0
cql3: functions: add helper class for internal scalar functions
db: functions: add stateless aggregate functions
db, cql3: move scalar_function from cql3/functions to db/functions
Now that all aggregate functions are derived from
stateless_aggregate_function_adapter, we can just fold its functionality
into the base class. This exposes stateless_aggregate_function to
all users of aggregate_function, so they can begin to benefit from
the transformation, though this patch doesn't touch those users.
The aggregate_function base class is partiallly devirtualized since
there is just a single implementation now.
The accumulator_for template is used to select the accumulator
type for aggregates. After refactoring, all that is needed from
it is to select the native type, so remove all the excess code.
Currently, we use __int128, but this has no direct counterpart
in CQL, so we can't express the accumulator type as part of a
CQL scalar function. Switch to varint which is a superset, although
slower.
Currently it works without this, but later unreversing will
be removed from another part of the stack, causing min/max
on reversed types to return incorrect results. Anticipate
that an unreverse the types during construction.
min() and max() had two implementations: one static (for each type in
a select list) and one dynamic (for compound types). Since the
dynamic implementation is sufficient, we only reimplement that. This
means we don't use the automarshalling helpers, since we don't do any
arithemetic on values apart from comparison, which is conveniently
provided by abstract_type.
Add a helper function to consolidate the internal native function
class and the automatic marshalling introduced in previous patches.
Since decaying a lambda into a function pointer (in order to
infer its signature) there are two overloads: one accepts a lambda
and decays it into a function pointer, the second accepts a function
pointer, infers its argument, and constructs the function object.
now that fmtlib provides fmt::join(). see
https://fmt.dev/latest/api.html#_CPPv4I0EN3fmt4joinE9join_viewIN6detail10iterator_tI5RangeEEN6detail10sentinel_tI5RangeEEERR5Range11string_view
there is not need to revent the wheel. so in this change, the homebrew
join() is replaced with fmt::join().
as fmt::join() returns an join_view(), this could improve the
performance under certain circumstances where the fully materialized
string is not needed.
please note, the goal of this change is to use fmt::join(), and this
change does not intend to improve the performance of existing
implementation based on "operator<<" unless the new implementation is
much more complicated. we will address the unnecessarily materialized
strings in a follow-up commit.
some noteworthy things related to this change:
* unlike the existing `join()`, `fmt::join()` returns a view. so we
have to materialize the view if what we expect is a `sstring`
* `fmt::format()` does not accept a view, so we cannot pass the
return value of `fmt::join()` to `fmt::format()`
* fmtlib does not format a typed pointer, i.e., it does not format,
for instance, a `const std::string*`. but operator<<() always print
a typed pointer. so if we want to format a typed pointer, we either
need to cast the pointer to `void*` or use `fmt::ptr()`.
* fmtlib is not able to pick up the overload of
`operator<<(std::ostream& os, const column_definition* cd)`, so we
have to use a wrapper class of `maybe_column_definition` for printing
a pointer to `column_definition`. since the overload is only used
by the two overloads of
`statement_restrictions::add_single_column_parition_key_restriction()`,
the operator<< for `const column_definition*` is dropped.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Add a helper that, given a C++ function, deduces its arguument types
and wraps the function in marshalling/unmarshalling code.
The native function expects non-null inputs, so an additional helper is
called to decide what to do if nulls are encountered. One such
helper is return_accumulator_on_null (since that's the default
behavior of aggregates), and the other is return_any_nonnull(),
useful for reductions.
We'll need many scalar functions to implement aggregates in terms
of scalars, so we add an internal_scalar_function class to reduce
boilerplate. The new class proxies the scalar function into a
native noncopyable_function provided by the constructor.
Previously, we moved cql3::functions::function to the
db::functions namespace, since functions are a part of the
data dictionary, which is independent of cql3. We do the
same now for scalar_function, since we wish to make use
of it in a new db::functions::stateless_aggregate_function.
A stub remains in cql3/functions to avoid churn.
The code for compare_endpoints originates at the dawn of time (bc034aeaec)
and is called on the fast path from storage_proxy via `sort_by_proximity`.
This series considerably reduces the function's footprint by:
1. carefully coding the many comparisons in the function so to reduce the number of conditional banches (apparently the compiler isn't doing a good enough job at optimizing it in this case)
2. avoid sstring copy in topology::get_{datacenter,rack}
Closes#12761
* github.com:scylladb/scylladb:
topology: optimize compare_endpoints
to_string: add print operators for std::{weak,partial}_ordering
utils: to_sstring: deinline std::strong_ordering print operator
move to_string.hh to utils/
test: network_topology: add test_topology_compare_endpoints
since "token()" computes the token for a given partition key,
if we pass the key of the wrong type, it should reject.
in this change,
* we validate the keys before returning the "token()" function.
* drop the "xfail" decorator from two of the tests. they pass
now after this fix.
* change the tests which previously passed the wrong number of
arguments containing null to "token()" and expect it to return
null, so they verify that "token()" should reject these
arguments with the expected error message.
Fixes#10448
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#12991
they are part of the CQL type system, and are "closer" to types.
let's move them into "types" directory.
the building systems are updated accordingly.
the source files referencing `types.hh` were updated using following
command:
```
find . -name "*.{cc,hh}" -exec sed -i 's/\"types.hh\"/\"types\/types.hh\"/' {} +
```
the source files under sstables include "types.hh", which is
indeed the one located under "sstables", so include "sstables/types.hh"
instea, so it's more explicit.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#12926
these warnings are found by Clang-17 after removing
`-Wno-unused-lambda-capture` and '-Wno-unused-variable' from
the list of disabled warnings in `configure.py`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Currently, if a UDA uses a UDF that's being replaced,
the UDA will still keep using the old UDF until the
node is restarted.
This patch fixes this behavior by checking all UDAs
when replacing a UDF and updating them if necessary.
Fixes#12709
When deciding whether two functions have the same
signature, we have to check if they have the same name
and parameter types. Additionally, if they're represented
by pointers, we need to check if any of them is a nullptr.
This logic is used multiple times, so it's extracted to
a separate function.
To use this function, the `used_by_user_aggregate` method
takes now a function instead of name and types list - we
can do it because we always use it with an existing user
function (that we're trying to drop).
The method will also be useful when we'll be not dropping,
but replacing a user function.
We will want to reuse the functions that we get from an aggregate
without making a deep copy, and it's only possible if we get
pointers from the aggregate instead of actual values.
When dropping a UDF we're checking if it's not begin used in any UDAs
and fail otherwise. However, we're only checking its state function
and final function, and it may also be used as its reduce function.
This patch adds the missing checks and a test for them.
Currently, when dropping a function, we only check if there exist
an aggregate that uses a function with the same name as its state
function or final function. This may cause the drop to fail even
when it's just another UDF with the same name that's used in the
aggregate, even when the actual dropped function is not used there.
This patch fixes this by checking whether not only the name of the
UDA's sfunc and finalfunc, but also their argument types.
Currently, nothing prevents us from dropping a user type
used in a user function, even though doing so may make us
unable to use the function correctly.
This patch prevents this behavior by checking all function
argument and return types when executing a drop type statement
and preventing it from completing if the type is referenced
by any of them.
Closes#12680
Now that we don't accept cql protocol version 1 or 2, we can
drop cql_serialization format everywhere, except when in the IDL
(since it's part of the inter-node protocol).
A few functions had duplicate versions, one with and one without
a cql_serialization_format parameter. They are deduplicated.
Care is taken that `partition_slice`, which communicates
the cql_serialization_format across nodes, still presents
a valid cql_serialization_format to other nodes when
transmitting itself and rejects protocol 1 and 2 serialization\
format when receiving. The IDL is unchanged.
One test checking the 16-bit serialization format is removed.
When executing a wasm UDF, most of the time is spent on
setting up the instance. To minimize its cost, we reuse
the instance using wasm::instance_cache.
This patch adds a wasm instance cache, that stores
a wasmtime instance for each UDF and scheduling group.
The instances are evicted using LRU strategy. The
cache may store some entries for the UDF after evicting
the instance, but they are evicted when the corresponding
UDF is dropped, which greatly limits their number.
The size of stored instances is estimated using the size
of their WASM memories. In order to be able to read the
size of memory, we require that the memory is exported
by the client.
Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>
`mock_get` was created only for forward_service use, thus it only checks for
aggregate functions if no declared function was found.
The reason for this function is, there is no serialization of `cql3::selection::selection`,
so functions lying underneath these selections has to be refound.
Most of this code is copied from `functions::get()`, however `functions::get()` is not used because it requires to
mock or serialize expressions and `functions::find()` is not enough,
because it does not search for dynamic aggregate functions
Moving `function`, `function_name` and `aggregate_function` into
db namespace to avoid including cql3 namespace into query-request.
For now, only minimal subset of cql3 function was moved to db.
Method reponsible for creating a token of given values is not meant to be
used with empty optionals. Thus, having requested a token of the columns
containing null values resulted with an exception being thrown. This kind
of behaviour was not compatible with the one applied in cassandra.
To fix this, before the computation of a token, it is checked whether
no null value is contained. If any value in the processed vector is null,
null value is returned.
Fixes: #10594Closes#10942
After fcb8d040 ("treewide: use Software Package Data Exchange
(SPDX) license identifiers"), many dual-licensed files were
left with empty comments on top. Remove them to avoid visual
noise.
Closes#10562
Makes final function and initial condition to be optional while
creating UDA. No final function means UDA returns final state
and defeult initial condition is `null`.
Fixes: #10324
As the name suggests, for UDFs defined as RETURNS NULL ON NULL
INPUT, we sometimes want to return nulls. However, currently
we do not return nulls. Instead, we fail on the null check in
init_arg_visitor. Fix by adding null handling before passing
arguments, same as in lua.
Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>
Closes#10298
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
Stop using database (and including database.hh) for schema related
purposes and use data_dictionary instead.
data_dictionary::database::real_database() is called from several
places, for these reasons:
- calling yet-to-be-converted code
- callers with a legitimate need to access data (e.g. system_keyspace)
but with the ::database accessor removed from query_processor.
We'll need to find another way to supply system_keyspace with
data access.
- to gain access to the wasm engine for testing whether used
defined functions compile. We'll have to find another way to
do this as well.
The change is a straightforward replacement. One case in
modification_statement had to change a capture, but everything else
was just a search-and-replace.
Some files that lost "database.hh" gained "mutation.hh", which they
previously had access to through "database.hh".
