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Merge 'storage_proxy: Include counter writes in...

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...  `writes_coordinator_outside_replica_set`' from Juliusz Stasiewicz

With this change, coordinator prefers himself as the "counter leader", so if
another endpoint is chosen as the leader, we know that coordinator was not a
member of replica set. With this guarantee we can increment
`scylla_storage_proxy_coordinator_writes_coordinator_outside_replica_set` metric
after electing different leader (that metric used to neglect the counter
updates).

The motivation for this change is to have more reliable way of counting
non-token-aware queries.

Fixes #4337
Closes #8282

* github.com:scylladb/scylla:
  storage_proxy: Include counter writes in `writes_coordinator_outside_replica_set`
  counters: Favor coordinator as leader
This commit is contained in:
Piotr Sarna
2021-03-16 12:14:30 +01:00
committed by Pekka Enberg
parent 972ea9900c f77d0f5439
commit 7961a28835
1 changed files with 14 additions and 3 deletions
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17
service/storage_proxy.cc
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@@ -2141,16 +2141,23 @@ gms::inet_address storage_proxy::find_leader_for_counter_update(const mutation&
throw exceptions::unavailable_exception(cl, block_for(ks, cl), 0);
}
auto local_endpoints = boost::copy_range<std::vector<gms::inet_address>>(live_endpoints | boost::adaptors::filtered([&] (auto&& ep) {
const auto my_address = utils::fb_utilities::get_broadcast_address();
// Early return if coordinator can become the leader (so one extra internode message can be
// avoided). With token-aware drivers this is the expected case, so we are doing it ASAP.
if (boost::algorithm::any_of_equal(live_endpoints, my_address)) {
return my_address;
}
const auto local_endpoints = boost::copy_range<std::vector<gms::inet_address>>(live_endpoints | boost::adaptors::filtered([&] (auto&& ep) {
return db::is_local(ep);
}));
if (local_endpoints.empty()) {
// FIXME: O(n log n) to get maximum
auto& snitch = locator::i_endpoint_snitch::get_local_snitch_ptr();
snitch->sort_by_proximity(utils::fb_utilities::get_broadcast_address(), live_endpoints);
snitch->sort_by_proximity(my_address, live_endpoints);
return live_endpoints[0];
} else {
// FIXME: favour ourselves to avoid additional hop?
static thread_local std::default_random_engine re{std::random_device{}()};
std::uniform_int_distribution<> dist(0, local_endpoints.size() - 1);
return local_endpoints[dist(re)];
@@ -2206,6 +2213,10 @@ future<> storage_proxy::mutate_counters(Range&& mutations, db::consistency_level
return std::move(m.fm);
}));
// Coordinator is preferred as the leader - if it's not selected we can assume
// that the query was non-token-aware and bump relevant metric.
get_stats().writes_coordinator_outside_replica_set += fms.size();
auto msg_addr = netw::messaging_service::msg_addr{ endpoint_and_mutations.first, 0 };
tracing::trace(tr_state, "Enqueuing counter update to {}", msg_addr);
f = _messaging.send_counter_mutation(msg_addr, timeout, std::move(fms), cl, tracing::make_trace_info(tr_state));