task_status contains a vector of children identities. If the number
of children is large, we may hit oversized allocation.
Change all types of children-related containers to chunked_vector.
Modify the children type returned from task manager API.
Fixes: scylladb#25795.
Closesscylladb/scylladb#25923
Currently, /task_manager/task_status_recursive/{task_id} and
/task_manager/task_status/{task_id} unregister queries task if it
has already finished.
The status should not disappear after being queried. Do not unregister
finished task when its status or recursive status is queried.
now that we are allowed to use C++23. we now have the luxury of using
`std::views::transform`.
in this change, we:
- replace `boost::adaptors::transformed` with `std::views::transform`
- use `fmt::join()` when appropriate where `boost::algorithm::join()`
is not applicable to a range view returned by `std::view::transform`.
- use `std::ranges::fold_left()` to accumulate the range returned by
`std::view::transform`
- use `std::ranges::fold_left()` to get the maximum element in the
range returned by `std::view::transform`
- use `std::ranges::min()` to get the minimal element in the range
returned by `std::view::transform`
- use `std::ranges::equal()` to compare the range views returned
by `std::view::transform`
- remove unused `#include <boost/range/adaptor/transformed.hpp>`
- use `std::ranges::subrange()` instead of `boost::make_iterator_range()`,
to feed `std::views::transform()` a view range.
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.
limitations:
there are still a couple places where we are still using
`boost::adaptors::transformed` due to the lack of a C++23 alternative
for `boost::join()` and `boost::adaptors::uniqued`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21700
When API user requests status of a virtual task, we first need to find
which virtual_task instance tracks given operation. While doing this we
gather some info regarding the task, but we don't utilize it.
Add virtual_task_hint that keeps info that was gathered during virtual
task lookup and pass it to virtual_task's methods so the info doesn't
need to be retrieved twice.
There are some bugs missed in task handler:
- wait_for_task does not wait until virtual tasks are done, but
returns the status immediately;
- wait_for_task suffers from use after return;
- get_status_recursively does not set the kind of task essentials.
Fix the aforementioned.
Virtual tasks are supported by get_task_status, abort_task and
wait_task.
Task status returned by get_task_status and wait_task:
- contains task_kind to indicate whether it's virtual (cluster) or
regular (node) task;
- children list apart from task_id contains node address of the task.
Contrary to regular tasks, which are per-operation, virtual tasks
are associated with the whole group of operations. There may be many
operations of each group performed at the same time. Info about each
running operation will be shown to a user through the API.
For virtual tasks, task manager imitates a regular task covering
each operation, but task_manager::tasks aren't actually created
in the memory. Instead, information (e.g. status) about the operation
is retrieved from associated service and passed to a user.
To hide most of the differences from user, task_handler class is created.
Task handler performs appropriate actions depending on task's kind.
However, users need to stay conscious about the kind of task, because:
- get_task_status and wait_task do not unregister virtual tasks;
- time for which a virtual tasks stays in task manager depends
on associated service and tasks' implementation;
- number of virtual task's children shown by get_tasks doesn't have
to be monotonous.
API is modified to use task_handler.
API-specific classes are moved to task_handler.{cc,hh}.
