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repair: Avoid searching all the rows in to_repair_rows_on_wire

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The repair_rows in row_list are sorted. It is only possible for the
current repair_row to share the same partition key with the last
repair_row inserted into repair_row_on_wire. So, no need to search from
the beginning of the repair_rows_on_wire to avoid quadratic complexity.
To fix, look at the last item in repair_rows_on_wire.

Fixes #4580
Message-Id: <08a8bfe90d1a6cf16b67c210151245879418c042.1561001271.git.asias@scylladb.com>

(cherry picked from commit b99c75429a)
This commit is contained in:
Asias He
2019-06-20 11:29:09 +08:00
committed by Tomasz Grabiec
parent 433cb93f7a
commit 31c4db83d8
2 changed files with 10 additions and 4 deletions
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1
repair/repair.hh
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@@ -295,6 +295,7 @@ public:
void push_mutation_fragment(frozen_mutation_fragment mf) { _mfs.push_back(std::move(mf)); }
};
using repair_row_on_wire = partition_key_and_mutation_fragments;
using repair_rows_on_wire = std::list<partition_key_and_mutation_fragments>;
enum class row_level_diff_detect_algorithm : uint8_t {

13
repair/row_level.cc
View File

@@ -1029,11 +1029,16 @@ private:
return do_with(repair_rows_on_wire(), std::move(row_list), [this] (repair_rows_on_wire& rows, std::list<repair_row>& row_list) {
return do_for_each(row_list, [this, &rows] (repair_row& r) {
auto pk = r.get_dk_with_hash()->dk.key();
auto it = std::find_if(rows.begin(), rows.end(), [&pk, s=_schema] (partition_key_and_mutation_fragments& row) { return pk.legacy_equal(*s, row.get_key()); });
if (it == rows.end()) {
rows.push_back(partition_key_and_mutation_fragments(std::move(pk), {std::move(r.get_frozen_mutation())}));
// No need to search from the beginning of the rows. Look at the end of repair_rows_on_wire is enough.
if (rows.empty()) {
rows.push_back(repair_row_on_wire(std::move(pk), {std::move(r.get_frozen_mutation())}));
} else {
it->push_mutation_fragment(std::move(r.get_frozen_mutation()));
auto& row = rows.back();
if (pk.legacy_equal(*_schema, row.get_key())) {
row.push_mutation_fragment(std::move(r.get_frozen_mutation()));
} else {
rows.push_back(repair_row_on_wire(std::move(pk), {std::move(r.get_frozen_mutation())}));
}
}
}).then([&rows] {
return std::move(rows);