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
The comparison operator (<=>) default implementation happens to exactly
match tombstone::compare(), so use the compiler-generated defaults. Also
default operator== and operator!= (these are not brought in by operator<=>).
These become slightly faster as they perform just an equality comparison,
not three-way compare.
shadowable_tombstone and row_tombstone depend on tombstone::compare(),
so convert them too in a similar way.
with_relational_operations.hh becomes unused, so delete it.
Tests: unit (dev)
Message-Id: <20200602055626.2874801-1-avi@scylladb.com>
This patch extracts out the relational operators in struct tombstone
to a class capable of generating them from a tri-compare function.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Checking bloom filters of sstables to compute max purgeable timestamp
for compaction is expensive in terms of CPU time. We can avoid
calculating it if we're not about to GC any tombstone.
This patch changes compacting functions to accept a function instead
of ready value for max_purgeable.
I verified that bloom filter operations no longer appear on flame
graphs during compaction-heavy workload (without tombstones).
Refs #1322.
