Previously, when result_generator's default constructor was called, the
_stats member variable remained uninitialized. This could lead to
undefined behavior in release builds where uninitialized values are
unpredictable, making issues difficult to debug.
This change initializes the pointer to nullptr, ensuring consistent
behavior across all build types and preventing potential memory-related
bugs.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#23073
The expression system uses managed_bytes_opt for values, but result_set
uses bytes_opt. This means that processing values from the result set
in expressions requires a copy.
Out of the two, managed_bytes_opt is the better choice, since it prevents
large contiguous allocations for large blobs. So we switch result_set
to use managed_bytes_opt. Users of the result_set API are adjusted.
The db::function interface is not modified to limit churn; instead we
convert the types on entry and exit. This will be adjusted in a following
patch.
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
Refs #7961Fixes#8014
Instead of doing a deep copy of input, we keep assume ownership and build
rows of the views therein, potentially retaining fragmented data as-is
avoiding premature linearization.
Note that this is not all sugar and flowers though. Any data access will
by nature be more expensive, and the view collections we create are
potentially just as expensive as copying for small cells.
Otoh, it allows writing code using this that avoids data copying,
depending on destination.
v2:
* Fixed wrong collection reserved in visitor
* Changed row index from shared ptr to ref
* Moved typedef
* Removed non-existing constructors
* Added const ref to index build
* Fixed raft usage after rebase
v3:
* Changed shared_ptr to unique
Currently, we cannot select more than 2^32 rows from a table because we are limited by types of
variables containing the numbers of rows. This patch changes these types and sets new limits.
The new limits take effect while selecting all rows from a table - custom limits of rows in a result
stay the same (2^32-1).
In classes which are being serialized and used in messaging, in order to be able to process queries
originating from older nodes, the top 32 bits of new integers are optional and stay at the end
of the class - if they're absent we assume they equal 0.
The backward compatibility was tested by querying an older node for a paged selection, using the
received paging_state with the same select statement on an upgraded node, and comparing the returned
rows with the result generated for the same query by the older node, additionally checking if the
paging_state returned by the upgraded node contained new fields with correct values. Also verified
if the older node simply ignores the top 32 bits of the remaining rows number when handling a query
with a paging_state originating from an upgraded node by generating and sending such a query to
an older node and checking the paging_state in the reply(using python driver).
Fixes#5101.
result_generator is a restricted alternative of result_set. It supports
only the simples cases, but is much cheaper as it passes data almost
directly from query::result to its visitor bypassing much of the CQL
layer.
