mirrors/scylladb
1
0
Fork 0
mirror of https://github.com/scylladb/scylladb.git synced 2026-05-19 22:32:04 +00:00
Code Issues Packages Projects Releases Wiki Activity

strong_consistency: allow QUORUM/LOCAL_QUORUM and ONE/LOCAL_ONE for reads

Browse Source 
We can execute strong consistent read queries in 2 ways:
- with QUORUM/LOCAL_QUORUM CL - this path executes `read_barrier()`
  before reading the data, which synchronizes Raft log with the leader.
  But to execute it, we need quorum of replicas
- with ONE/LOCAL_ONE CL - this path just reads data from one replica
  without any synchronization (not implemented yet)
This commit is contained in:
Michał Jadwiszczak
2026-05-12 23:13:29 +02:00
parent 68f0cf6fac
commit d073097ebf
1 changed files with 10 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
cql3/statements/strong_consistency/select_statement.cc
View File

@@ -8,6 +8,7 @@
#include "select_statement.hh"
#include "db/consistency_level_type.hh"
#include "query/query-request.hh"
#include "cql3/query_processor.hh"
#include "service/strong_consistency/coordinator.hh"
@@ -17,10 +18,19 @@ namespace cql3::statements::strong_consistency {
using result_message = cql_transport::messages::result_message;
static void validate_consistency_level(const db::consistency_level& cl) {
if (cl != db::consistency_level::QUORUM && cl != db::consistency_level::LOCAL_QUORUM &&
cl != db::consistency_level::ONE && cl != db::consistency_level::LOCAL_ONE) {
throw exceptions::invalid_request_exception("Strongly consistent reads must use QUORUM/LOCAL_QUORUM or ONE/LOCAL_ONE consistency level");
}
}
future<::shared_ptr<result_message>> select_statement::do_execute(query_processor& qp,
service::query_state& state,
const query_options& options) const
{
validate_consistency_level(options.get_consistency());
const auto key_ranges = _restrictions->get_partition_key_ranges(options);
if (key_ranges.size() != 1 || !query::is_single_partition(key_ranges[0])) {
throw exceptions::invalid_request_exception("Strongly consistent queries can only target a single partition");