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Summary: Speedup findsetnewold

Reviewers: florijan, buda, teon.banek

Reviewed By: florijan

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1252
This commit is contained in:
Dominik Gleich 2018-02-28 10:29:05 +01:00
parent 99375a4b47
commit 4c8f924965
1 changed files with 32 additions and 20 deletions
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52
src/distributed/remote_cache.hpp
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@ -50,36 +50,48 @@ class RemoteCache {
*/
void FindSetOldNew(tx::transaction_id_t tx_id, int worker_id, gid::Gid gid,
TRecord *&old_record, TRecord *&new_record) {
std::lock_guard<std::mutex> guard{lock_};
auto found = cache_.find(gid);
if (found != cache_.end()) {
old_record = found->second.first.get();
new_record = found->second.second.get();
} else {
auto remote =
remote_data_clients_.RemoteElement<TRecord>(worker_id, tx_id, gid);
old_record = remote.get();
new_record = nullptr;
cache_[gid] =
std::make_pair<rec_uptr, rec_uptr>(std::move(remote), nullptr);
{
std::lock_guard<std::mutex> guard(lock_);
auto found = cache_.find(gid);
if (found != cache_.end()) {
old_record = found->second.first.get();
new_record = found->second.second.get();
return;
}
}
auto remote =
remote_data_clients_.RemoteElement<TRecord>(worker_id, tx_id, gid);
// This logic is a bit strange because we need to make sure that someone
// else didn't get a response and updated the cache before we did and we
// need a lock for that, but we also need to check if we can now return
// that result - otherwise we could get incosistent results for remote
// FindSetOldNew
std::lock_guard<std::mutex> guard(lock_);
auto it_pair = cache_.emplace(
gid, std::make_pair<rec_uptr, rec_uptr>(std::move(remote), nullptr));
old_record = it_pair.first->second.first.get();
new_record = it_pair.first->second.second.get();
}
void AdvanceCommand() {
// TODO implement.
// The effect of this should be that the next call to FindSetOldNew will do
// an RPC and not use the cached stuff.
// The effect of this should be that the next call to FindSetOldNew will
// do an RPC and not use the cached stuff.
//
// Not sure if it's OK to just flush the cache? I *think* that after a
// global advance-command, all the existing RecordAccessors will be calling
// Reconstruct, so perhaps just flushing is the correct sollution, even
// though we'll have pointers to nothing.
// global advance-command, all the existing RecordAccessors will be
// calling Reconstruct, so perhaps just flushing is the correct sollution,
// even though we'll have pointers to nothing.
}
/** Sets the given records as (new, old) data for the given gid. */
void emplace(gid::Gid gid, rec_uptr old_record, rec_uptr new_record) {
std::lock_guard<std::mutex> guard{lock_};
// We can't replace existing data because some accessors might be using it.
// We can't replace existing data because some accessors might be using
// it.
// TODO - consider if it's necessary and OK to copy just the data content.
auto found = cache_.find(gid);
if (found != cache_.end())
@ -91,8 +103,8 @@ class RemoteCache {
/// Removes all the cached data. All the pointers to that data still held by
/// RecordAccessors will become invalid and must never be dereferenced after
/// this call. To make a RecordAccessor valid again Reconstruct must be called
/// on it. This is typically done after the command advanced.
/// this call. To make a RecordAccessor valid again Reconstruct must be
/// called on it. This is typically done after the command advanced.
void ClearCache() {
std::lock_guard<std::mutex> guard{lock_};
cache_.clear();