chore: get rid of kv_args and replace it with slices to full_args

Signed-off-by: Roman Gershman <[email protected]>

src/server/container_utils.cc

@@ -40,14 +40,12 @@ OpResult<std::pair<DbSlice::ConstIterator, unsigned>> FindFirstReadOnly(const Db
  int req_obj_type) {
  DCHECK(!args.Empty());
 
- unsigned i = 0;
- for (string_view key : args) {
- OpResult<DbSlice::ConstIterator> res = db_slice.FindReadOnly(cntx, key, req_obj_type);
+ for (auto it = args.begin(); it != args.end(); ++it) {
+ OpResult<DbSlice::ConstIterator> res = db_slice.FindReadOnly(cntx, *it, req_obj_type);
  if (res)
- return make_pair(res.value(), i);
+ return make_pair(res.value(), unsigned(it.index()));
  if (res.status() != OpStatus::KEY_NOTFOUND)
  return res.status();
- ++i;
  }
 
  VLOG(2) << "FindFirst not found";
@@ -119,8 +117,8 @@ OpResult<ShardFFResult> FindFirstNonEmpty(Transaction* trans, int req_obj_type)
  auto comp = [trans](const OpResult<FFResult>& lhs, const OpResult<FFResult>& rhs) {
  if (!lhs || !rhs)
  return lhs.ok();
- size_t i1 = trans->ReverseArgIndex(std::get<ShardId>(*lhs), std::get<unsigned>(*lhs));
- size_t i2 = trans->ReverseArgIndex(std::get<ShardId>(*rhs), std::get<unsigned>(*rhs));
+ size_t i1 = std::get<1>(*lhs);
+ size_t i2 = std::get<1>(*rhs);
  return i1 < i2;
  };
 

src/server/journal/types.h

@@ -42,15 +42,17 @@ struct Entry : public EntryBase {
  struct Payload {
  std::string_view cmd;
  std::variant<CmdArgList, // Parts of a full command.
- ShardArgs  // Command and its shard parts.
- >
- args;
+ ShardArgs, // Command and its shard parts.
+ ArgSlice>
+ args; // Command and its shard parts.
 
  Payload() = default;
  Payload(std::string_view c, CmdArgList a) : cmd(c), args(a) {
  }
  Payload(std::string_view c, const ShardArgs& a) : cmd(c), args(a) {
  }
+ Payload(std::string_view c, ArgSlice a) : cmd(c), args(a) {
+ }
  };
 
  Entry(TxId txid, Op opcode, DbIndex dbid, uint32_t shard_cnt,

src/server/json_family.cc

@@ -1543,12 +1543,14 @@ void JsonFamily::MGet(CmdArgList args, ConnectionContext* cntx) {
  continue;
 
  vector<OptString>& res = mget_resp[sid];
- for (size_t j = 0; j < res.size(); ++j) {
- if (!res[j])
+ ShardArgs shard_args = transaction->GetShardArgs(sid);
+ unsigned src_index = 0;
+ for (auto it = shard_args.begin(); it != shard_args.end(); ++it, ++src_index) {
+ if (!res[src_index])
  continue;
 
- uint32_t indx = transaction->ReverseArgIndex(sid, j);
- results[indx] = std::move(res[j]);
+ uint32_t dst_indx = it.index();
+ results[dst_indx] = std::move(res[src_index]);
  }
  }
 

src/server/list_family.cc

@@ -158,6 +158,22 @@ struct CircularMessages {
 // Used to recover logs for BLPOP failures. See OpBPop.
 thread_local CircularMessages debugMessages{50};
 
+// A bit awakward translation from a single key to ShardArgs.
+// We create a mutable slice (which will never be mutated) from the key, then we create
+// a CmdArgList of size 1 that references mslice and finally
+// we reference the first element in the CmdArgList via islice.
+struct SingleArg {
+ MutableSlice mslice;
+ IndexSlice islice{0, 1};
+
+ SingleArg(string_view arg) : mslice(const_cast<char*>(arg.data()), arg.size()) {
+ }
+
+ ShardArgs Get() {
+ return ShardArgs{CmdArgList{&mslice, 1}, absl::MakeSpan(&islice, 1)};
+ }
+};
+
 class BPopPusher {
  public:
  BPopPusher(string_view pop_key, string_view push_key, ListDir popdir, ListDir pushdir);
@@ -448,7 +464,10 @@ OpResult<string> MoveTwoShards(Transaction* trans, string_view src, string_view
  // hack, again. since we hacked which queue we are waiting on (see RunPair)
  // we must clean-up src key here manually. See RunPair why we do this.
  // in short- we suspended on "src" on both shards.
- shard->blocking_controller()->FinalizeWatched(ArgSlice{&src, 1}, t);
+ //
+
+ SingleArg single_arg{src};
+ shard->blocking_controller()->FinalizeWatched(single_arg.Get(), t);
  }
  } else {
  DVLOG(1) << "Popping value from list: " << key;
@@ -873,7 +892,8 @@ OpResult<string> BPopPusher::RunSingle(ConnectionContext* cntx, time_point tp) {
  return op_res;
  }
 
- auto wcb = [&](Transaction* t, EngineShard* shard) { return ShardArgs{&this->pop_key_, 1}; };
+ SingleArg single_arg{pop_key_};
+ auto wcb = [&](Transaction* t, EngineShard* shard) { return single_arg.Get(); };
 
  const auto key_checker = [](EngineShard* owner, const DbContext& context, Transaction*,
  std::string_view key) -> bool {
@@ -900,11 +920,13 @@ OpResult<string> BPopPusher::RunPair(ConnectionContext* cntx, time_point tp) {
  return op_res;
  }
 
+ SingleArg single_arg(this->pop_key_);
+
  // a hack: we watch in both shards for pop_key but only in the source shard it's relevant.
  // Therefore we follow the regular flow of watching the key but for the destination shard it
  // will never be triggerred.
  // This allows us to run Transaction::Execute on watched transactions in both shards.
- auto wcb = [&](Transaction* t, EngineShard* shard) { return ArgSlice{&this->pop_key_, 1}; };
+ auto wcb = [&](Transaction* t, EngineShard* shard) -> ShardArgs { return single_arg.Get(); };
 
  const auto key_checker = [](EngineShard* owner, const DbContext& context, Transaction*,
  std::string_view key) -> bool {

src/server/stream_family.cc

@@ -2989,17 +2989,19 @@ void XReadImpl(CmdArgList args, std::optional<ReadOpts> opts, ConnectionContext*
  continue;
 
  vector<RecordVec>& results = xread_resp[sid];
+ unsigned src_index = 0;
+ ShardArgs shard_args = cntx->transaction->GetShardArgs(sid);
 
- for (size_t i = 0; i < results.size(); ++i) {
- if (results[i].size() == 0) {
+ for (auto it = shard_args.begin(); it != shard_args.end(); ++it, ++src_index) {
+ if (results[src_index].size() == 0) {
  continue;
  }
 
  resolved_streams++;
 
  // Add the stream records ordered by the original stream arguments.
- size_t indx = cntx->transaction->ReverseArgIndex(sid, i);
- res[indx - opts->streams_arg] = std::move(results[i]);
+ size_t dst_indx = it.index();
+ res[dst_indx - opts->streams_arg] = std::move(results[src_index]);
  }
  }
 

src/server/string_family.cc

@@ -275,13 +275,15 @@ void OpMSet(const OpArgs& op_args, const ShardArgs& args, atomic_bool* success)
  SetCmd sg(op_args, false);
 
  size_t index = 0;
+ bool partial = false;
  for (auto it = args.begin(); it != args.end(); ++it) {
  string_view key = *it;
  ++it;
  string_view value = *it;
  DVLOG(1) << "MSet " << key << ":" << value;
  if (sg.Set(params, key, value) != OpStatus::OK) { // OOM for example.
  success->store(false);
+ partial = true;
  break;
  }
  index += 2;
@@ -290,18 +292,29 @@ void OpMSet(const OpArgs& op_args, const ShardArgs& args, atomic_bool* success)
  if (auto journal = op_args.shard->journal(); journal) {
  // We write a custom journal because an OOM in the above loop could lead to partial success, so
  // we replicate only what was changed.
- string_view cmd;
- ArgSlice cmd_args;
- if (index == 0) {
- // All shards must record the tx was executed for the replica to execute it, so we send a PING
- // in case nothing was changed
- cmd = "PING";
+ if (partial) {
+ string_view cmd;
+ ArgSlice cmd_args;
+ vector<string_view> store_args(index);
+ if (index == 0) {
+ // All shards must record the tx was executed for the replica to execute it, so we send a
+ // PING in case nothing was changed
+ cmd = "PING";
+ } else {
+ // journal [0, i)
+ cmd = "MSET";
+ unsigned i = 0;
+ for (string_view arg : args) {
+ store_args[i++] = arg;
+ if (i >= store_args.size())
+ break;
+ }
+ cmd_args = absl::MakeSpan(store_args);
+ }
+ RecordJournal(op_args, cmd, cmd_args, op_args.tx->GetUniqueShardCnt());
  } else {
- // journal [0, i)
- cmd = "MSET";
- cmd_args = ArgSlice(args.begin(), index);
+ RecordJournal(op_args, "MSET", args, op_args.tx->GetUniqueShardCnt());
  }
- RecordJournal(op_args, cmd, cmd_args, op_args.tx->GetUniqueShardCnt());
  }
 }
 
@@ -1163,16 +1176,17 @@ void StringFamily::MGet(CmdArgList args, ConnectionContext* cntx) {
  src.storage_list->next = res.storage_list;
  res.storage_list = src.storage_list;
  src.storage_list = nullptr;
-
- for (size_t j = 0; j < src.resp_arr.size(); ++j) {
- if (!src.resp_arr[j])
+ ShardArgs shard_args = transaction->GetShardArgs(sid);
+ unsigned src_indx = 0;
+ for (auto it = shard_args.begin(); it != shard_args.end(); ++it, ++src_indx) {
+ if (!src.resp_arr[src_indx])
  continue;
 
- uint32_t indx = transaction->ReverseArgIndex(sid, j);
+ uint32_t indx = it.index();
 
- res.resp_arr[indx] = std::move(src.resp_arr[j]);
+ res.resp_arr[indx] = std::move(src.resp_arr[src_indx]);
  if (cntx->protocol() == Protocol::MEMCACHE) {
- res.resp_arr[indx]->key = ArgS(args, indx);
+ res.resp_arr[indx]->key = *it;
  }
  }
  }