Milestone 3 Phase 3.5: Extract hostgroup routing and locking decisions from session

include/MySQL_HostGroup_Routing.h

@@ -0,0 +1,62 @@
+#ifndef MYSQL_HOSTGROUP_ROUTING_H
+#define MYSQL_HOSTGROUP_ROUTING_H
+
+#include <string>
+
+/**
+ * @struct MySQL_Routing_Session_State
+ * @brief Represents the session state relevant for hostgroup routing decisions.
+ */
+struct MySQL_Routing_Session_State {
+	int current_hostgroup{-1};
+	int default_hostgroup{-1};
+	int locked_on_hostgroup{-1};
+	int transaction_persistent_hostgroup{-1};
+	int last_hg_affected_rows{-1};
+	int warning_in_hg{-1};
+	bool autocommit{true};
+	int autocommit_on_hostgroup{-1};
+	bool mirror{false};
+};
+
+/**
+ * @struct MySQL_Routing_QPO_State
+ * @brief Represents the Query Processor Output relevant for hostgroup routing decisions.
+ */
+struct MySQL_Routing_QPO_State {
+	int destination_hostgroup{-1};
+	bool lock_hostgroup{false}; // Derived from query parsing or QPO
+	bool is_show_warnings{false}; // Derived from query parsing
+	bool is_last_insert_id{false}; // Derived from query parsing
+	bool is_version_query{false}; // Derived from query parsing
+};
+
+/**
+ * @struct MySQL_Routing_Result
+ * @brief Represents the output of the hostgroup routing decision.
+ */
+struct MySQL_Routing_Result {
+	int new_current_hostgroup{-1};
+	int new_locked_on_hostgroup{-1};
+	bool lock_hostgroup{false};
+	bool error{false};
+	std::string error_msg;
+};
+
+/**
+ * @brief Resolves the target hostgroup and locking decisions based on session and QPO state.
+ * 
+ * This is a pure function designed to be easily testable.
+ * 
+ * @param sess_state Current session state.
+ * @param qpo_state Query Processor Output state.
+ * @param set_query_lock_on_hostgroup Global configuration (mysql-set_query_lock_on_hostgroup).
+ * @return MySQL_Routing_Result The routing decision.
+ */
+MySQL_Routing_Result resolve_hostgroup_routing(
+	const MySQL_Routing_Session_State& sess_state,
+	const MySQL_Routing_QPO_State& qpo_state,
+	int set_query_lock_on_hostgroup
+);
+
+#endif // MYSQL_HOSTGROUP_ROUTING_H

include/PgSQL_HostGroup_Routing.h

@@ -0,0 +1,54 @@
+#ifndef PGSQL_HOSTGROUP_ROUTING_H
+#define PGSQL_HOSTGROUP_ROUTING_H
+
+#include <string>
+
+/**
+ * @struct PgSQL_Routing_Session_State
+ * @brief Represents the session state relevant for hostgroup routing decisions in PostgreSQL.
+ */
+struct PgSQL_Routing_Session_State {
+	int current_hostgroup{-1};
+	int default_hostgroup{-1};
+	int locked_on_hostgroup{-1};
+	int transaction_persistent_hostgroup{-1};
+};
+
+/**
+ * @struct PgSQL_Routing_QPO_State
+ * @brief Represents the Query Processor Output relevant for hostgroup routing decisions in PostgreSQL.
+ */
+struct PgSQL_Routing_QPO_State {
+	int destination_hostgroup{-1};
+	bool lock_hostgroup{false}; // Derived from query parsing
+};
+
+/**
+ * @struct PgSQL_Routing_Result
+ * @brief Represents the output of the hostgroup routing decision for PostgreSQL.
+ */
+struct PgSQL_Routing_Result {
+	int new_current_hostgroup{-1};
+	int new_locked_on_hostgroup{-1};
+	bool lock_hostgroup{false};
+	bool error{false};
+	std::string error_msg;
+};
+
+/**
+ * @brief Resolves the target hostgroup and locking decisions based on session and QPO state.
+ * 
+ * This is a pure function designed to be easily testable.
+ * 
+ * @param sess_state Current session state.
+ * @param qpo_state Query Processor Output state.
+ * @param set_query_lock_on_hostgroup Global configuration (pgsql-set_query_lock_on_hostgroup).
+ * @return PgSQL_Routing_Result The routing decision.
+ */
+PgSQL_Routing_Result resolve_pgsql_hostgroup_routing(
+	const PgSQL_Routing_Session_State& sess_state,
+	const PgSQL_Routing_QPO_State& qpo_state,
+	int set_query_lock_on_hostgroup
+);
+
+#endif // PGSQL_HOSTGROUP_ROUTING_H

lib/Makefile

@@ -88,7 +88,7 @@ MYCXXFLAGS := $(STDCPP) $(MYCFLAGS) $(PSQLCH) $(PSQLGA) $(PSQL31) $(PSQLFFTO) $(
 default: libproxysql.a
 .PHONY: default
 
-_OBJ_CXX := ProxySQL_GloVars.oo network.oo debug.oo configfile.oo Query_Cache.oo SpookyV2.oo MySQL_Authentication.oo gen_utils.oo sqlite3db.oo mysql_connection.oo MySQL_HostGroups_Manager.oo mysql_data_stream.oo MySQL_Thread.oo MySQL_Session.oo MySQL_Protocol.oo mysql_backend.oo Query_Processor.oo MySQL_Query_Processor.oo PgSQL_Query_Processor.oo  ProxySQL_Admin.oo ProxySQL_Config.oo ProxySQL_Restapi.oo MySQL_Monitor.oo MySQL_Logger.oo log_utils.oo thread.oo MySQL_PreparedStatement.oo ProxySQL_Cluster.oo ClickHouse_Authentication.oo ClickHouse_Server.oo ProxySQL_Statistics.oo Chart_bundle_js.oo ProxySQL_HTTP_Server.oo ProxySQL_RESTAPI_Server.oo font-awesome.min.css.oo main-bundle.min.css.oo MySQL_Variables.oo c_tokenizer.oo proxysql_utils.oo proxysql_coredump.oo proxysql_sslkeylog.oo \
+_OBJ_CXX := ProxySQL_GloVars.oo network.oo debug.oo configfile.oo Query_Cache.oo SpookyV2.oo MySQL_Authentication.oo gen_utils.oo sqlite3db.oo mysql_connection.oo MySQL_HostGroups_Manager.oo mysql_data_stream.oo MySQL_Thread.oo MySQL_Session.oo MySQL_HostGroup_Routing.oo PgSQL_Session.oo PgSQL_HostGroup_Routing.oo MySQL_Protocol.oo mysql_backend.oo Query_Processor.oo MySQL_Query_Processor.oo PgSQL_Query_Processor.oo  ProxySQL_Admin.oo ProxySQL_Config.oo ProxySQL_Restapi.oo MySQL_Monitor.oo MySQL_Logger.oo log_utils.oo thread.oo MySQL_PreparedStatement.oo ProxySQL_Cluster.oo ClickHouse_Authentication.oo ClickHouse_Server.oo ProxySQL_Statistics.oo Chart_bundle_js.oo ProxySQL_HTTP_Server.oo ProxySQL_RESTAPI_Server.oo font-awesome.min.css.oo main-bundle.min.css.oo MySQL_Variables.oo c_tokenizer.oo proxysql_utils.oo proxysql_coredump.oo proxysql_sslkeylog.oo \
 	sha256crypt.oo \
 	BaseSrvList.oo BaseHGC.oo Base_HostGroups_Manager.oo \
 	QP_rule_text.oo QP_query_digest_stats.oo \

lib/MonitorHealthDecision.cpp

@@ -11,6 +11,7 @@
  */
 
 #include "MonitorHealthDecision.h"
+#include <cstdint>
 
 bool should_shun_on_connect_errors(
 	unsigned int errors_this_second,

lib/MySQL_HostGroup_Routing.cpp

@@ -0,0 +1,72 @@
+#include "MySQL_HostGroup_Routing.h"
+
+MySQL_Routing_Result resolve_hostgroup_routing(
+	const MySQL_Routing_Session_State& sess_state,
+	const MySQL_Routing_QPO_State& qpo_state,
+	int set_query_lock_on_hostgroup
+) {
+	MySQL_Routing_Result result;
+	result.new_current_hostgroup = sess_state.current_hostgroup;
+	result.new_locked_on_hostgroup = sess_state.locked_on_hostgroup;
+	result.lock_hostgroup = false;
+	result.error = false;
+	result.error_msg = "";
+
+	// 1. Mirroring (highest priority)
+	if (sess_state.mirror) {
+		result.new_current_hostgroup = qpo_state.destination_hostgroup;
+		return result;
+	}
+
+	// 2. SHOW WARNINGS / SHOW COUNT(*) WARNINGS
+	if (qpo_state.is_show_warnings) {
+		if (sess_state.warning_in_hg > -1) {
+			result.new_current_hostgroup = sess_state.warning_in_hg;
+		}
+		return result;
+	}
+
+	// 3. LAST_INSERT_ID / @@IDENTITY
+	if (qpo_state.is_last_insert_id) {
+		if (sess_state.last_hg_affected_rows >= 0) {
+			result.new_current_hostgroup = sess_state.last_hg_affected_rows;
+			return result;
+		}
+	}
+
+	// 4. Default routing from QPO or Transaction Persistence
+	if (sess_state.transaction_persistent_hostgroup != -1) {
+		result.new_current_hostgroup = sess_state.transaction_persistent_hostgroup;
+	} else {
+		if (qpo_state.destination_hostgroup >= 0) {
+			result.new_current_hostgroup = qpo_state.destination_hostgroup;
+		} else {
+			// qpo_state.destination_hostgroup < 0 means no override from QPO
+			result.new_current_hostgroup = sess_state.default_hostgroup;
+		}
+	}
+
+	// 5. Hostgroup Locking Decisions (mysql-set_query_lock_on_hostgroup)
+	if (set_query_lock_on_hostgroup == 1) {
+		// Algorithm introduced in ProxySQL 2.0.6
+		if (result.new_locked_on_hostgroup < 0) {
+			if (qpo_state.lock_hostgroup) {
+				result.lock_hostgroup = true;
+				result.new_locked_on_hostgroup = result.new_current_hostgroup;
+			}
+		}
+
+		if (result.new_locked_on_hostgroup >= 0) {
+			if (result.new_current_hostgroup != result.new_locked_on_hostgroup) {
+				result.error = true;
+				result.error_msg = "ProxySQL Error: connection is locked to hostgroup " + 
+								   std::to_string(result.new_locked_on_hostgroup) + 
+								   " but trying to reach hostgroup " + 
+								   std::to_string(result.new_current_hostgroup);
+				return result;
+			}
+		}
+	}
+
+	return result;
+}