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Add maybe feasible approach example

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This commit is contained in:
Marko Budiselic 2022-04-29 05:00:12 +02:00
parent d47cc290ef
commit e662206fd1
3 changed files with 44 additions and 0 deletions
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9
src/query/interpreter.cpp
View File

@ -2210,6 +2210,10 @@ void RunTriggersIndividually(const utils::SkipList<Trigger> &triggers, Interpret
if (maybe_constraint_violation.HasError()) {
const auto &constraint_violation = maybe_constraint_violation.GetError();
switch (constraint_violation.type) {
case storage::ConstraintViolation::Type::UNABLE_TO_REPLICATE: {
spdlog::warn("Unable to replicate");
break;
}
case storage::ConstraintViolation::Type::EXISTENCE: {
const auto &label_name = db_accessor.LabelToName(constraint_violation.label);
MG_ASSERT(constraint_violation.properties.size() == 1U);
@ -2273,6 +2277,11 @@ void Interpreter::Commit() {
if (maybe_constraint_violation.HasError()) {
const auto &constraint_violation = maybe_constraint_violation.GetError();
switch (constraint_violation.type) {
case storage::ConstraintViolation::Type::UNABLE_TO_REPLICATE: {
reset_necessary_members();
throw QueryException("Unable to replicate to SYNC replica");
break;
}
case storage::ConstraintViolation::Type::EXISTENCE: {
auto label_name = execution_db_accessor_->LabelToName(constraint_violation.label);
MG_ASSERT(constraint_violation.properties.size() == 1U);

2
src/storage/v2/constraints.hpp
View File

@ -46,6 +46,8 @@ struct ConstraintViolation {
enum class Type {
EXISTENCE,
UNIQUE,
// TODO(gitbuda): Total workaround, rename/move the ConstraintViloation struct and add empty data state.
UNABLE_TO_REPLICATE,
};
Type type;

33
src/storage/v2/storage.cpp
View File

@ -849,6 +849,29 @@ utils::BasicResult<ConstraintViolation, void> Storage::Accessor::Commit(
// Save these so we can mark them used in the commit log.
uint64_t start_timestamp = transaction_.start_timestamp;
// Aboring here and after the locked block obviously has an issue if
// replica goes down and back up during the execution of the locked block of
// code.
// Not enough, before the actual commit check all SYNC replicas for availability.
bool unable_to_sync_replicate = false;
const auto check_replicas = [&]() {
storage_->replication_clients_.WithLock([&](auto &clients) {
for (auto &client : clients) {
// Exclusively SYNC replicas have to be available to commit the transaction.
if (client->Mode() == replication::ReplicationMode::SYNC && !client->Timeout().has_value() &&
client->State() == replication::ReplicaState::INVALID) {
unable_to_sync_replicate = true;
}
}
});
};
check_replicas();
if (unable_to_sync_replicate) {
Abort();
return ConstraintViolation{ConstraintViolation::Type::UNABLE_TO_REPLICATE, LabelId(), std::set<PropertyId>{}};
}
{
std::unique_lock<utils::SpinLock> engine_guard(storage_->engine_lock_);
commit_timestamp_.emplace(storage_->CommitTimestamp(desired_commit_timestamp));
@ -917,10 +940,20 @@ utils::BasicResult<ConstraintViolation, void> Storage::Accessor::Commit(
engine_guard.unlock();
});
// NOTE: This will finish/commit the transaction.
storage_->commit_log_->MarkFinished(start_timestamp);
// TODO(gitbuda): Maybe the solution here is to 1. mark 2. check all the replicas 3. unmark if required
}
}
// TODO(gitbuda): This doesn't have any effect because (it will only if the
// constraints are also violated).
check_replicas();
if (unable_to_sync_replicate) {
Abort();
return ConstraintViolation{ConstraintViolation::Type::UNABLE_TO_REPLICATE, LabelId(), std::set<PropertyId>{}};
}
if (unique_constraint_violation) {
Abort();
return *unique_constraint_violation;