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cql: sum of abs RFs diffs cannot exceed 1 in ALTER tablets KS

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Tablets load balancer is unable to process more than a single pending
replica, thus ALTER tablets KS cannot accept an ALTER statement which
would result in creating 2+ pending replicas, hence it has to validate
if the sum of absoulte differences of RFs specified in the statement is
not greter than 1.

(cherry picked from commit ee56bbfe61)
This commit is contained in:
Piotr Smaron
2024-08-23 21:52:22 +02:00
committed by Mergify
parent c7b5571766
commit c73d0ffbaa
2 changed files with 32 additions and 14 deletions
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18
cql3/statements/alter_keyspace_statement.cc
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@@ -44,16 +44,15 @@ future<> cql3::statements::alter_keyspace_statement::check_access(query_processo
return state.has_keyspace_access(_name, auth::permission::ALTER);
}
// We want to ensure that each DC's RF is going to change by at most 1
static bool validate_rf_difference(const std::string& curr_rf, const std::string& new_rf) {
static unsigned get_abs_rf_diff(const std::string& curr_rf, const std::string& new_rf) {
try {
return std::abs(std::stoi(curr_rf) - std::stoi(new_rf)) <= 1;
return std::abs(std::stoi(curr_rf) - std::stoi(new_rf));
} catch (std::invalid_argument const& ex) {
on_internal_error(mylogger, format("validate_rf_difference expects integer arguments, "
"but got curr_rf:{} and new_rf:{}", curr_rf, new_rf));
on_internal_error(mylogger, fmt::format("get_abs_rf_diff expects integer arguments, "
"but got curr_rf:{} and new_rf:{}", curr_rf, new_rf));
} catch (std::out_of_range const& ex) {
on_internal_error(mylogger, format("validate_rf_difference expects integer arguments to fit into `int` type, "
"but got curr_rf:{} and new_rf:{}", curr_rf, new_rf));
on_internal_error(mylogger, fmt::format("get_abs_rf_diff expects integer arguments to fit into `int` type, "
"but got curr_rf:{} and new_rf:{}", curr_rf, new_rf));
}
}
@@ -87,6 +86,7 @@ void cql3::statements::alter_keyspace_statement::validate(query_processor& qp, c
const std::map<sstring, sstring>& current_rf_per_dc = ks.metadata()->strategy_options();
auto new_rf_per_dc = _attrs->get_replication_options();
new_rf_per_dc.erase(ks_prop_defs::REPLICATION_STRATEGY_CLASS_KEY);
unsigned total_abs_rfs_diff = 0;
for (const auto& [new_dc, new_rf] : new_rf_per_dc) {
sstring old_rf = "0";
if (auto new_dc_in_current_mapping = current_rf_per_dc.find(new_dc);
@@ -99,8 +99,8 @@ void cql3::statements::alter_keyspace_statement::validate(query_processor& qp, c
// first we need to report non-existing DCs, then if RFs aren't changed by too much.
continue;
}
if (!validate_rf_difference(old_rf, new_rf)) {
throw exceptions::invalid_request_exception("Cannot modify replication factor of any DC by more than 1 at a time.");
if (total_abs_rfs_diff += get_abs_rf_diff(old_rf, new_rf); total_abs_rfs_diff >= 2) {
throw exceptions::invalid_request_exception("Only one DC's RF can be changed at a time and not by more than 1");
}
}
}