Add support for PostgreSQL transaction command aliases and ROLLBACK AND CHAIN

include/PgSQL_ExplicitTxnStateMgr.h

@@ -41,7 +41,8 @@ struct TxnCmd {
         ROLLBACK, 
         SAVEPOINT, 
         RELEASE, 
-        ROLLBACK_TO 
+        ROLLBACK_TO,
+        ROLLBACK_AND_CHAIN
     } type = Type::UNKNOWN;
     std::string savepoint; //< The name of the savepoint, if applicable.
 };
@@ -63,6 +64,7 @@ private:
     TxnCmd parse_rollback(size_t& pos) noexcept;
     TxnCmd parse_savepoint(size_t& pos) noexcept;
     TxnCmd parse_release(size_t& pos) noexcept;
+    TxnCmd parse_start(size_t& pos) noexcept;
 
     // Helpers
     static std::string to_lower(std::string_view s) noexcept {
@@ -101,7 +103,7 @@ private:
 
     void start_transaction();
     void commit();
-    void rollback();
+    void rollback(bool rollback_and_chain);
     bool add_savepoint(std::string_view name);
     bool rollback_to_savepoint(std::string_view name);
     bool release_savepoint(std::string_view name);

lib/PgSQL_ExplicitTxnStateMgr.cpp

@@ -86,7 +86,7 @@ void PgSQL_ExplicitTxnStateMgr::commit() {
     verify_server_variables(session);
 }
 
-void PgSQL_ExplicitTxnStateMgr::rollback() {
+void PgSQL_ExplicitTxnStateMgr::rollback(bool rollback_and_chain) {
 
     if (transaction_state.empty()) {
         proxy_warning("Received ROLLBACK command. There is no transaction in progress\n");
@@ -124,11 +124,15 @@ void PgSQL_ExplicitTxnStateMgr::rollback() {
         verify_server_variables(session);
 	}
 
-    // Clear savepoints and reset the initial snapshot
-    for (auto& tran_state : transaction_state) {
-        reset_variable_snapshot(tran_state);
+    // Keep the transaction state intact when executing ROLLBACK AND CHAIN
+    if (rollback_and_chain == false) {
+        // Clear savepoints and reset the initial snapshot
+        for (auto& tran_state : transaction_state) {
+            reset_variable_snapshot(tran_state);
+        }
+        transaction_state.clear();
     }
-    transaction_state.clear();
+
     savepoint.clear();
 }
 
@@ -296,7 +300,10 @@ bool PgSQL_ExplicitTxnStateMgr::handle_transaction(std::string_view input) {
         commit();
         break;
     case TxnCmd::ROLLBACK:
-        rollback();
+        rollback(false);
+        break;
+	case TxnCmd::ROLLBACK_AND_CHAIN:
+        rollback(true);
         break;
     case TxnCmd::SAVEPOINT:
         return add_savepoint(cmd.savepoint);
@@ -350,12 +357,14 @@ TxnCmd PgSQL_TxnCmdParser::parse(std::string_view input, bool in_transaction_mod
 
     if (in_transaction_mode == true) {
         if (first == "begin") cmd.type = TxnCmd::BEGIN;
+		else if (first == "start") cmd = parse_start(pos);
         else if (first == "savepoint") cmd = parse_savepoint(pos);
         else if (first == "release") cmd = parse_release(pos);
         else if (first == "rollback") cmd = parse_rollback(pos);
     } else {
-        if (first == "commit") cmd.type = TxnCmd::COMMIT;
-        else if (first == "rollback" || (first == "abort")) cmd = parse_rollback(pos);
+        if (first == "commit" || first == "end") cmd.type = TxnCmd::COMMIT;
+		else if (first == "abort") cmd.type = TxnCmd::ROLLBACK;
+        else if (first == "rollback") cmd = parse_rollback(pos);
     }
     return cmd;
 }
@@ -368,6 +377,11 @@ TxnCmd PgSQL_TxnCmdParser::parse_rollback(size_t& pos) noexcept {
         cmd.type = TxnCmd::ROLLBACK_TO;
         if (++pos < tokens.size() && to_lower(tokens[pos]) == "savepoint") pos++;
         if (pos < tokens.size()) cmd.savepoint = tokens[pos++];
+    } else if (pos < tokens.size() && to_lower(tokens[pos]) == "and") {
+        if (++pos < tokens.size() && to_lower(tokens[pos]) == "chain") {
+            cmd.type = TxnCmd::ROLLBACK_AND_CHAIN;
+			pos++;
+        }
     }
     return cmd;
 }
@@ -384,3 +398,12 @@ TxnCmd PgSQL_TxnCmdParser::parse_release(size_t& pos) noexcept {
     if (pos < tokens.size()) cmd.savepoint = tokens[pos++];
     return cmd;
 }
+
+TxnCmd PgSQL_TxnCmdParser::parse_start(size_t& pos) noexcept {
+    TxnCmd cmd{ TxnCmd::UNKNOWN };
+    if (pos < tokens.size() && to_lower(tokens[pos]) == "transaction") {
+        cmd.type = TxnCmd::BEGIN;
+		pos++;
+    }
+    return cmd;
+}

lib/PgSQL_Session.cpp

@@ -517,22 +517,17 @@ bool PgSQL_Session::handler_CommitRollback(PtrSize_t* pkt) {
 	if (pkt->size <= 5) { return false; }
 	char c = ((char*)pkt->ptr)[5];
 	bool ret = false;
-	if (c == 'c' || c == 'C') {
-		if (pkt->size >= sizeof("commit") + 5) {
-			if (strncasecmp((char*)"commit", (char*)pkt->ptr + 5, 6) == 0) {
-				__sync_fetch_and_add(&PgHGM->status.commit_cnt, 1);
-				ret = true;
-			}
+	if (c == 'c' || c == 'C' || c == 'e' || c == 'E') {
+		if ((pkt->size >= 5 + 6 && strncasecmp("commit", (char*)pkt->ptr + 5, 6) == 0) ||
+			(pkt->size >= 5 + 3 && strncasecmp("end", (char*)pkt->ptr + 5, 3) == 0)) {
+			__sync_fetch_and_add(&PgHGM->status.commit_cnt, 1);
+			ret = true;
 		}
-	}
-	else {
-		if (c == 'r' || c == 'R') {
-			if (pkt->size >= sizeof("rollback") + 5) {
-				if (strncasecmp((char*)"rollback", (char*)pkt->ptr + 5, 8) == 0) {
-					__sync_fetch_and_add(&PgHGM->status.rollback_cnt, 1);
-					ret = true;
-				}
-			}
+	} else if (c == 'r' || c == 'R' || c == 'a' || c == 'A') {
+		if ((pkt->size >= 5 + 8 && strncasecmp("rollback", (char*)pkt->ptr + 5, 8) == 0) ||
+			(pkt->size >= 5 + 5 && strncasecmp("abort", (char*)pkt->ptr + 5, 5) == 0)) {
+			__sync_fetch_and_add(&PgHGM->status.rollback_cnt, 1);
+			ret = true;
 		}
 	}
 
@@ -568,7 +563,7 @@ bool PgSQL_Session::handler_CommitRollback(PtrSize_t* pkt) {
 			status = WAITING_CLIENT_DATA;
 		}
 		l_free(pkt->size, pkt->ptr);
-		if (c == 'c' || c == 'C') {
+		if (c == 'c' || c == 'C' || c == 'e' || c == 'E') {
 			__sync_fetch_and_add(&PgHGM->status.commit_cnt_filtered, 1);
 		} else {
 			__sync_fetch_and_add(&PgHGM->status.rollback_cnt_filtered, 1);