"
This series changes hinted handoff to work with `frozen_mutation`s
instead of naked `mutation`s. Instead of unfreezing a mutation from
the commitlog entry and then freezing it again for sending, now we'll
just keep the read, frozen mutation.
Tests: unit(release)
"
* 'hh-manager-cleanup/v1' of https://github.com/duarten/scylla:
db/hints/manager: Use frozen_mutation instead of mutation
db/hints/manager: Use database::find_schema()
db/commitlog/commitlog_entry: Allow moving the contained mutation
service/storage_proxy: send_to_endpoint overload accepting frozen_mutation
service/storage_proxy: Build a shared_mutation from a frozen_mutation
service/storage_proxy: Lift frozen_mutation_and_schema
service/storage_proxy: Allow non-const ranges in mutate_prepare()
(cherry picked from commit 1891779e64)
So far commitlog was using contiguous buffers for storing the data that
is about to be written to disk. It was able to coalesce small writes so
that multiple small mutations would use the same buffer, but if a
muation was large the commitlog would attempt to allocate a single,
appropriately large buffer. This excessively stresses the memory
allocator and may cause memory fragmentation to become an issue. The
solution is to use fixed-size buffers of 128 kB, which is the standard
buffer size in Scylla and keep large values fragmented.
Currently commitlog_entry_writer constructor calculates serialized size
before it is knows if a schema should be included into the entry. The
result is never used since it is recalculated when schema information is
supplied. The patch removes needless calculation.
Message-Id: <20170614114607.GA21915@scylladb.com>
- introcduced "seastarx.hh" header, which does a "using namespace seastar";
- 'net' namespace conflicts with seastar::net, renamed to 'netw'.
- 'transport' namespace conflicts with seastar::transport, renamed to
cql_transport.
- "logger" global variables now conflict with logger global type, renamed
to xlogger.
- other minor changes
It is safe to copy column_mapping accros shards. Such guarantee comes at
the cost of performance.
This patch makes commitlog_entry_writer use IDL generated writer to
serialise commitlog_entry so that column_mapping is not copied. This
also simplifies commitlog_entry itself.
Performance difference tested with:
perf_simple_query -c4 --write --duration 60
(medians)
before after diff
write 79434.35 89247.54 +12.3%
Goal is to calculate a size that is lesser or equal than the
segment-dependent size.
This was originally written by Tomasz, and featured in his submission
"commitlog: Handle overload more gracefully"
Extracted here so it sits clearly in a different patch.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
