Replace rand() with lock-free Xoshiro128++ PRNG

Author: rahim-kanji

lib/PgSQL_HostGroups_Manager.cpp

@@ -820,7 +820,7 @@ PgSQL_HostGroups_Manager::PgSQL_HostGroups_Manager() {
 		static const char alphanum[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 		rand_del[0] = '-';
 		for (int i = 1; i < 6; i++) {
-			rand_del[i] = alphanum[rand() % (sizeof(alphanum) - 1)];
+			rand_del[i] = alphanum[rand_fast() % (sizeof(alphanum) - 1)];
 		}
 		rand_del[6] = '-';
 		rand_del[7] = 0;
@@ -2208,11 +2208,12 @@ PgSQL_SrvC *PgSQL_HGC::get_random_MySrvC(char * gtid_uuid, uint64_t gtid_trxid,
 
 
 		unsigned int k;
-		if (New_sum > 32768) {
-			k=rand()%New_sum;
-		} else {
-			k=fastrand()%New_sum;
-		}
+		//if (New_sum > 32768) {
+		//	k=rand()%New_sum;
+		//} else {
+		//	k=fastrand()%New_sum;
+		//}
+		k = rand_fast() % New_sum;
 		k++;
 		New_sum=0;
 
@@ -2341,11 +2342,12 @@ PgSQL_Connection * PgSQL_SrvConnList::get_random_MyConn(PgSQL_Session *sess, boo
 		}
 	}
 	if (l && ff==false && needs_warming==false) {
-		if (l>32768) {
-			i=rand()%l;
-		} else {
-			i=fastrand()%l;
-		}
+		//if (l>32768) {
+		//	i=rand()%l;
+		//} else {
+		//	i=fastrand()%l;
+		//}
+		i = rand_fast() % l;
 		if (sess && sess->client_myds && sess->client_myds->myconn && sess->client_myds->myconn->userinfo) {
 			PgSQL_Connection * client_conn = sess->client_myds->myconn;
 			get_random_MyConn_inner_search(i, l, conn_found_idx, connection_quality_level, number_of_matching_session_variables, client_conn);

lib/PgSQL_Protocol.cpp

@@ -404,7 +404,7 @@ bool PgSQL_Protocol::generate_pkt_initial_handshake(bool send, void** _ptr, unsi
 			// Fallback method: using a basic pseudo-random generator
 			srand((unsigned int)time(NULL));  
 			for (size_t i = 0; i < sizeof((*myds)->tmp_login_salt); i++) {
-				(*myds)->tmp_login_salt[i] = rand() % 256;  
+				(*myds)->tmp_login_salt[i] = rand_fast() % 256;
 			}
 		}
 		pgpkt.write_generic(type, "ib", PG_PKT_AUTH_MD5, (*myds)->tmp_login_salt, sizeof((*myds)->tmp_login_salt));

lib/PgSQL_Thread.cpp

@@ -2943,7 +2943,7 @@ void PgSQL_Thread::run() {
 #ifdef IDLE_THREADS
 		if (GloVars.global.idle_threads) {
 			if (idle_maintenance_thread == false) {
-				int r = rand() % (GloPTH->num_threads);
+				int r = rand_fast() % (GloPTH->num_threads);
 				PgSQL_Thread* thr = GloPTH->pgsql_threads_idles[r].worker;
 				worker_thread_assigns_sessions_to_idle_thread(thr);
 				worker_thread_gets_sessions_from_idle_thread();
@@ -2967,7 +2967,7 @@ void PgSQL_Thread::run() {
 			// The delay for the active-wait is a fraction of 'poll_timeout'. Since other
 			// threads may be waiting on poll for further operations, checks are meaningless
 			// until that timeout expires (other workers make progress).
-			usleep(std::min(std::max(pgsql_thread___poll_timeout/20, 10000), 40000) + (rand() % 2000));
+			usleep(std::min(std::max(pgsql_thread___poll_timeout/20, 10000), 40000) + (rand_fast() % 2000));
 		}
 
 		proxy_debug(PROXY_DEBUG_NET, 7, "poll_timeout=%u\n", mypolls.poll_timeout);
@@ -3124,7 +3124,7 @@ void PgSQL_Thread::run() {
 		__run_skip_2 :
 		if (GloVars.global.idle_threads && idle_maintenance_thread) {
 			// this is an idle thread
-			unsigned int w = rand() % (GloPTH->num_threads);
+			unsigned int w = rand_fast() % (GloPTH->num_threads);
 			PgSQL_Thread* thr = GloPTH->pgsql_threads[w].worker;
 			if (resume_mysql_sessions->len) {
 				idle_thread_assigns_sessions_to_worker_thread(thr);

lib/Query_Processor.cpp

@@ -228,7 +228,7 @@ Query_Processor<QP_DERIVED>::Query_Processor(int _query_rules_fast_routing_algor
 		rand_del[1] = '-';
 		rand_del[2] = '-';
 		for (int i = 3; i < 11; i++) {
-			rand_del[i] = alphanum[rand() % (sizeof(alphanum) - 1)];
+			rand_del[i] = alphanum[rand_fast() % (sizeof(alphanum) - 1)];
 		}
 		rand_del[11] = '-';
 		rand_del[12] = '-';
@@ -1878,9 +1878,9 @@ void Query_Processor<QP_DERIVED>::update_query_digest(uint64_t digest_total, uin
 	TypeConnInfo* ui, unsigned long long t, unsigned long long n, const char* client_addr, unsigned long long rows_affected,
 	unsigned long long rows_sent) {
 	QP_query_digest_stats* qds;
-	pthread_rwlock_wrlock(&digest_rwlock);
+	std::unordered_map<uint64_t, void*>::iterator it;
 
-	std::unordered_map<uint64_t, void *>::iterator it;
+	pthread_rwlock_wrlock(&digest_rwlock);
 	it=digest_umap.find(digest_total);
 	if (it != digest_umap.end()) {
 		// found