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canonical_mutation: make the data type non-contiguous

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The canonical_mutation type can contain a large mutation, particularly
when the mutation is a result of converting a big schema. Its data
was stored in a field of type 'bytes', which is non-contiguous and
may cause a large allocation.
This is fixed by simply changing the type to 'bytes_ostream', which is
fragmented. The change is compatible because the idl type 'bytes' is compatible
with 'bytes_ostream' as a result of dcf794b, and all canonical_mutations's
methods use the field as an input stream (ser::as_input_stream), which can
be used on 'bytes_ostream' too.

Fixes #8074

Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>

Closes #8075
This commit is contained in:
Wojciech Mitros
2021-02-11 12:52:23 +01:00
committed by Tomasz Grabiec
parent f884104eed
commit 1819be5ebc
2 changed files with 5 additions and 7 deletions
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6
canonical_mutation.cc
View File

@@ -37,7 +37,7 @@
#include "idl/mutation.dist.impl.hh"
#include <iostream>
canonical_mutation::canonical_mutation(bytes data)
canonical_mutation::canonical_mutation(bytes_ostream data)
: _data(std::move(data))
{ }
@@ -45,8 +45,7 @@ canonical_mutation::canonical_mutation(const mutation& m)
{
mutation_partition_serializer part_ser(*m.schema(), m.partition());
bytes_ostream out;
ser::writer_of_canonical_mutation<bytes_ostream> wr(out);
ser::writer_of_canonical_mutation<bytes_ostream> wr(_data);
std::move(wr).write_table_id(m.schema()->id())
.write_schema_version(m.schema()->version())
.write_key(m.key())
@@ -54,7 +53,6 @@ canonical_mutation::canonical_mutation(const mutation& m)
.partition([&] (auto wr) {
part_ser.write(std::move(wr));
}).end_canonical_mutation();
_data = to_bytes(out.linearize());
}
utils::UUID canonical_mutation::column_family_id() const {

6
canonical_mutation.hh
View File

@@ -32,9 +32,9 @@
// Safe to access from other shards via const&.
// Safe to pass serialized across nodes.
class canonical_mutation {
bytes _data;
bytes_ostream _data;
public:
explicit canonical_mutation(bytes);
explicit canonical_mutation(bytes_ostream);
explicit canonical_mutation(const mutation&);
canonical_mutation(canonical_mutation&&) = default;
@@ -51,7 +51,7 @@ public:
utils::UUID column_family_id() const;
const bytes& representation() const { return _data; }
const bytes_ostream& representation() const { return _data; }
friend std::ostream& operator<<(std::ostream& os, const canonical_mutation& cm);
};