cql3: fix documentation and avoid unnecessary copy in execute_paged_internal

- Remove duplicate comment block in header file
- Avoid copying query_state when it's provided by using a reference
  instead of a copy in the ternary expression

Co-authored-by: ptrsmrn <124208650+ptrsmrn@users.noreply.github.com>

auth/service.cc

@@ -884,15 +884,6 @@ future<> migrate_to_auth_v2(db::system_keyspace& sys_ks, ::service::raft_group0_
             ::service::client_state cs(::service::client_state::internal_tag{}, tc);
             ::service::query_state qs(cs, empty_service_permit());
 
-            auto rows = co_await qp.execute_internal(
-                    seastar::format("SELECT * FROM {}.{}", meta::legacy::AUTH_KS, cf_name),
-                    db::consistency_level::ALL,
-                    qs,
-                    {},
-                    cql3::query_processor::cache_internal::no);
-            if (rows->empty()) {
-                continue;
-            }
             std::vector<sstring> col_names;
             for (const auto& col : schema->all_columns()) {
                 col_names.push_back(col.name_as_cql_string());
@@ -901,7 +892,14 @@ future<> migrate_to_auth_v2(db::system_keyspace& sys_ks, ::service::raft_group0_
             for (size_t i = 1; i < col_names.size(); ++i) {
                 val_binders_str += ", ?";
             }
-            for (const auto& row : *rows) {
+
+            co_await qp.query_internal(
+                    seastar::format("SELECT * FROM {}.{}", meta::legacy::AUTH_KS, cf_name),
+                    db::consistency_level::ALL,
+                    qs,
+                    {},
+                    1000,
+                    [&](const cql3::untyped_result_set_row& row) -> future<stop_iteration> {
                 std::vector<data_value_or_unset> values;
                 for (const auto& col : schema->all_columns()) {
                     if (row.has(col.name_as_text())) {
@@ -925,7 +923,8 @@ future<> migrate_to_auth_v2(db::system_keyspace& sys_ks, ::service::raft_group0_
                             format("expecting single insert mutation, got {}", muts.size()));
                 }
                 co_yield std::move(muts[0]);
-            }
+                co_return stop_iteration::no;
+            });
         }
         co_yield co_await sys_ks.make_auth_version_mutation(ts,
                 db::system_keyspace::auth_version_t::v2);
@@ -934,7 +933,7 @@ future<> migrate_to_auth_v2(db::system_keyspace& sys_ks, ::service::raft_group0_
             start_operation_func,
             std::move(gen),
             as,
-            std::nullopt);
+            get_raft_timeout());
 }
 
 }

cql3/query_processor.cc

@@ -886,9 +886,10 @@ future<> query_processor::for_each_cql_result(
 }
 
 future<::shared_ptr<untyped_result_set>>
-query_processor::execute_paged_internal(internal_query_state& state) {
+query_processor::execute_paged_internal(internal_query_state& state, service::query_state* query_state) {
     state.p->statement->validate(*this, service::client_state::for_internal_calls());
-    auto qs = query_state_for_internal_call();
+    auto default_qs = query_state ? std::nullopt : std::make_optional(query_state_for_internal_call());
+    auto& qs = query_state ? *query_state : *default_qs;
     ::shared_ptr<cql_transport::messages::result_message> msg =
       co_await state.p->statement->execute(*this, qs, *state.opts, std::nullopt);
 
@@ -925,6 +926,20 @@ query_processor::execute_paged_internal(internal_query_state& state) {
     co_return ::make_shared<untyped_result_set>(msg);
 }
 
+future<> query_processor::for_each_cql_result(
+        cql3::internal_query_state& state,
+        service::query_state& query_state,
+        noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set::row&)> f) {
+    do {
+        auto msg = co_await execute_paged_internal(state, &query_state);
+        for (auto& row : *msg) {
+            if ((co_await f(row)) == stop_iteration::yes) {
+                co_return;
+            }
+        }
+    } while (has_more_results(state));
+}
+
 future<::shared_ptr<untyped_result_set>>
 query_processor::execute_internal(
         const sstring& query_string,
@@ -1202,6 +1217,17 @@ future<> query_processor::query_internal(
     co_return co_await for_each_cql_result(query_state, std::move(f));
 }
 
+future<> query_processor::query_internal(
+        const sstring& query_string,
+        db::consistency_level cl,
+        service::query_state& query_state,
+        const data_value_list& values,
+        int32_t page_size,
+        noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f) {
+    auto paged_state = create_paged_state(query_string, cl, values, page_size);
+    co_return co_await for_each_cql_result(paged_state, query_state, std::move(f));
+}
+
 future<> query_processor::query_internal(
         const sstring& query_string,
         noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f) {

cql3/query_processor.hh

@@ -332,6 +332,29 @@ public:
             int32_t page_size,
             noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f);
 
+    /*!
+     * \brief iterate over all cql results using paging with a custom query_state (for timeout control)
+     *
+     * You can use placeholders in the query, the statement will only be prepared once.
+     *
+     * query_string - the cql string, can contain placeholders
+     * cl - consistency level of the query
+     * query_state - query state with custom timeout configuration
+     * values - values to be substituted for the placeholders in the query
+     * page_size - maximum page size
+     * f - a function to be run on each row of the query result,
+     *     if the function returns stop_iteration::yes the iteration will stop
+     *
+     * \note This function is optimized for convenience, not performance.
+     */
+    future<> query_internal(
+            const sstring& query_string,
+            db::consistency_level cl,
+            service::query_state& query_state,
+            const data_value_list& values,
+            int32_t page_size,
+            noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f);
+
     /*
      * \brief iterate over all cql results using paging
      * An overload of query_internal without query parameters
@@ -501,11 +524,14 @@ private:
             int32_t page_size);
 
     /*!
-     * \brief run a query using paging
+     * \brief run a query using paging with an optional custom query_state (for timeout control)
+     *
+     * state - internal query state containing prepared statement and options
+     * query_state - optional query state with custom timeout configuration (defaults to internal query state)
      *
      * \note Optimized for convenience, not performance.
      */
-    future<::shared_ptr<untyped_result_set>> execute_paged_internal(internal_query_state& state);
+    future<::shared_ptr<untyped_result_set>> execute_paged_internal(internal_query_state& state, service::query_state* query_state = nullptr);
 
     /*!
      * \brief iterate over all results using paging, accept a function that returns a future
@@ -516,6 +542,21 @@ private:
             cql3::internal_query_state& state,
             noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f);
 
+    /*!
+     * \brief iterate over all results using paging with a custom query_state (for timeout control)
+     *
+     * state - internal query state containing prepared statement and options
+     * query_state - query state with custom timeout configuration
+     * f - a function to be run on each row of the query result,
+     *     if the function returns stop_iteration::yes the iteration will stop
+     *
+     * \note Optimized for convenience, not performance.
+     */
+    future<> for_each_cql_result(
+            cql3::internal_query_state& state,
+            service::query_state& query_state,
+            noncopyable_function<future<stop_iteration>(const cql3::untyped_result_set_row&)> f);
+
     /*!
      * \brief check, based on the state if there are additional results
      * Users of the paging, should not use the internal_query_state directly