Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

fix: deduplicate mget response #4184

Merged
merged 1 commit into from
Nov 25, 2024
Merged

fix: deduplicate mget response #4184

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
29 changes: 24 additions & 5 deletions src/server/string_family.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -529,14 +529,29 @@ SinkReplyBuilder::MGetResponse OpMGet(util::fb2::BlockingCounter wait_bc, uint8_
auto& db_slice = t->GetDbSlice(shard->shard_id());

SinkReplyBuilder::MGetResponse response(keys.Size());
absl::InlinedVector<DbSlice::ConstIterator, 32> iters(keys.Size());

struct Item {
DbSlice::ConstIterator it;
int source_index = -1; // in case of duplicate keys, points to the first occurrence.
};

absl::InlinedVector<Item, 32> items(keys.Size());
absl::flat_hash_map<string_view, unsigned> key_index;

// First, fetch all iterators and count total size ahead
size_t total_size = 0;
unsigned index = 0;

key_index.reserve(keys.Size());
for (string_view key : keys) {
auto [it, inserted] = key_index.try_emplace(key, index);
if (!inserted) { // duplicate -> point to the first occurrence.
items[index++].source_index = it->second;
continue;
}

auto it_res = db_slice.FindReadOnly(t->GetDbContext(), key, OBJ_STRING);
if (auto& dest = iters[index++]; it_res) {
if (auto& dest = items[index++].it; it_res) {
dest = *it_res;
total_size += (*it_res)->second.Size();
}
Expand All @@ -547,10 +562,14 @@ SinkReplyBuilder::MGetResponse OpMGet(util::fb2::BlockingCounter wait_bc, uint8_
char* next = response.storage_list->data;
bool fetch_mcflag = fetch_mask & FETCH_MCFLAG;
bool fetch_mcver = fetch_mask & FETCH_MCVER;
for (size_t i = 0; i < iters.size(); ++i) {
auto it = iters[i];
if (it.is_done())
for (size_t i = 0; i < items.size(); ++i) {
auto it = items[i].it;
if (it.is_done()) {
if (items[i].source_index >= 0) {
response.resp_arr[i] = response.resp_arr[items[i].source_index];
}
continue;
}

auto& resp = response.resp_arr[i].emplace();

Expand Down
Loading