Issue #88.

Fixed fixed a bug with locking on rules.

lib/Standard_Query_Processor.cpp

@@ -30,6 +30,7 @@ static re2_t * compile_query_rule(QP_rule_t *qr) {
 };
 
 static void __delete_query_rule(QP_rule_t *qr) {
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 5, "Deleting rule in %p : rule_id:%d, active:%d, username=%s, schemaname=%s, flagIN:%d, %smatch_pattern=\"%s\", flagOUT:%d replace_pattern=\"%s\", destination_hostgroup:%d, apply:%d\n", qr, qr->rule_id, qr->active, qr->username, qr->schemaname, qr->flagIN, (qr->negate_match_pattern ? "(!)" : "") , qr->match_pattern, qr->flagOUT, qr->replace_pattern, qr->destination_hostgroup, qr->apply);
 	if (qr->username)
 		free(qr->username);
 	if (qr->schemaname)
@@ -47,7 +48,11 @@ static void __delete_query_rule(QP_rule_t *qr) {
 	free(qr);
 };
 
+// delete all the query rules in a Query Processor Table
+// Note that this function is called by GloQPro with &rules (generic table)
+//     and is called by each mysql thread with _thr_SQP_rules (per thread table)
 static void __reset_rules(std::vector<QP_rule_t *> * qrs) {
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 5, "Resetting rules in Query Processor Table %p\n", qrs);
 	if (qrs==NULL) return;
 	QP_rule_t *qr;
 	for (std::vector<QP_rule_t *>::iterator it=qrs->begin(); it!=qrs->end(); ++it) {
@@ -58,6 +63,7 @@ static void __reset_rules(std::vector<QP_rule_t *> * qrs) {
 }
 
 
+// per thread variables
 __thread unsigned int _thr_SQP_version;
 __thread std::vector<QP_rule_t *> * _thr_SQP_rules;
 
@@ -72,6 +78,7 @@ protected:
 
 public:
 Standard_Query_Processor() {
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Initializing Query Processor with version=0\n");
 	spinlock_rwlock_init(&rwlock);
 	version=0;
 };
@@ -80,13 +87,16 @@ virtual ~Standard_Query_Processor() {
 	__reset_rules(&rules);
 };
 
+// This function is called by each thread when it starts. It create a Query Processor Table for each thread
 virtual void init_thread() {
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Initializing Per-Thread Query Processor Table with version=0\n");
 	_thr_SQP_version=0;
 	_thr_SQP_rules=new std::vector<QP_rule_t *>;
 };
 
 
 virtual void end_thread() {
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Destroying Per-Thread Query Processor Table with version=%d\n", _thr_SQP_version);
 	__reset_rules(_thr_SQP_rules);
 	delete _thr_SQP_rules;
 };
@@ -120,6 +130,7 @@ virtual QP_rule_t * new_query_rule(int rule_id, bool active, char *username, cha
 	newQR->cache_ttl=cache_ttl;
 	newQR->apply=apply;
 	newQR->regex_engine=NULL;
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 5, "Creating new rule in %p : rule_id:%d, active:%d, username=%s, schemaname=%s, flagIN:%d, %smatch_pattern=\"%s\", flagOUT:%d replace_pattern=\"%s\", destination_hostgroup:%d, apply:%d\n", newQR, newQR->rule_id, newQR->active, newQR->username, newQR->schemaname, newQR->flagIN, (newQR->negate_match_pattern ? "(!)" : "") , newQR->match_pattern, newQR->flagOUT, newQR->replace_pattern, newQR->destination_hostgroup, newQR->apply);
 	return newQR;
 };
 
@@ -164,13 +175,17 @@ virtual bool insert(QP_rule_t *qr, bool lock) {
 
 virtual void sort(bool lock) {
 	if (lock) spin_wrlock(&rwlock);
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Sorting rules\n");
 	std::sort (rules.begin(), rules.end(), rules_sort_comp_function);
 	if (lock) spin_wrunlock(&rwlock);
 };
 
+// when commit is called, the version number is increased and the this will trigger the mysql threads to get a new Query Processor Table
+// The operation is asynchronous
 virtual void commit() {
 	spin_wrlock(&rwlock);
 	__sync_add_and_fetch(&version,1);
+	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Increasing version number to %d - all threads will notice this and refresh their rules\n", version);
 	spin_wrunlock(&rwlock);
 };
 
@@ -183,22 +198,25 @@ virtual QP_out_t * process_mysql_query(MySQL_Session *sess, void *ptr, unsigned
 	query[len]=0;
 	if (__sync_add_and_fetch(&version,0) > _thr_SQP_version) {
 		// update local rules;
+		proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Detected a changed in version. Global:%d , local:%d . Refreshing...\n", version, _thr_SQP_version);
 		spin_rdlock(&rwlock);
 		_thr_SQP_version=__sync_add_and_fetch(&version,0);
 		__reset_rules(_thr_SQP_rules);
-		spin_rdunlock(&rwlock);
 		QP_rule_t *qr1;
 		QP_rule_t *qr2;
 		for (std::vector<QP_rule_t *>::iterator it=rules.begin(); it!=rules.end(); ++it) {
 			qr1=*it;
 			if (qr1->active) {
+				proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Copying Query Rule id: %d\n", qr1->rule_id);
 				qr2=new_query_rule(qr1->rule_id, qr1->active, qr1->username, qr1->schemaname, qr1->flagIN, qr1->match_pattern, qr1->negate_match_pattern, qr1->flagOUT, qr1->replace_pattern, qr1->destination_hostgroup, qr1->cache_ttl, qr1->apply);
 				if (qr2->match_pattern) {
+					proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Compiling regex for rule_id: %d, match_pattern: \n", qr2->rule_id, qr2->match_pattern);
 					qr2->regex_engine=(void *)compile_query_rule(qr2);
 				}
 				_thr_SQP_rules->push_back(qr2);
 			}
 		}
+		spin_rdunlock(&rwlock); // unlock should be after the copy
 	}
 	QP_rule_t *qr;
 	re2_t *re2p;
@@ -218,6 +236,7 @@ __exit_process_mysql_query:
 	return ret;
 };
 
+// this function is called by mysql_session to free the result generated by process_mysql_query()
 virtual void delete_QP_out(QP_out_t *o) {
 	l_free(sizeof(QP_out_t),o);
 };