Improve performance due to issue #606

jemalloc configured with purge:decay_time
Temporary disabled jemalloc to test a heap profiler (heaptrack)
MySQL_ResultSet::buffer_to_PSarrayOut() calls realloc() if the buffer preallocated is too big
MySQL_Session::writeout() sends as much data as possible to the client

.gitignore

@@ -101,3 +101,6 @@ deps/protobuf/protobuf-2.6.1/
 test/.vagrant
 .DS_Store
 proxysql-tests.ini
+
+#heaptrack
+heaptrack.*

lib/MySQL_Protocol.cpp

@@ -1535,6 +1535,9 @@ bool MySQL_ResultSet::get_resultset(PtrSizeArray *PSarrayFinal) {
 void MySQL_ResultSet::buffer_to_PSarrayOut() {
 	if (buffer_used==0)
 		return;	// exit immediately if the buffer is empty
+	if (buffer_used < RESULTSET_BUFLEN/2) {
+		buffer=(unsigned char *)realloc(buffer,buffer_used);
+	}
 	PSarrayOUT->add(buffer,buffer_used);
 	buffer=(unsigned char *)malloc(RESULTSET_BUFLEN);
 	buffer_used=0;

lib/MySQL_Session.cpp

@@ -319,7 +319,29 @@ void MySQL_Session::writeout() {
 	//if (server_myds) server_myds->set_pollout();
 	if (client_myds) {
 		if (mirror==false) {
-			client_myds->write_to_net_poll();
+			bool runloop=false;
+			int retbytes=client_myds->write_to_net_poll();
+			if (retbytes==QUEUE_T_DEFAULT_SIZE) { // optimization to solve memory bloat
+				runloop=true;
+			}
+			while (runloop) {
+				runloop=false; // the default
+				client_myds->array2buffer_full();
+				//nfds_t nfds=1;
+				struct pollfd fds;
+				fds.fd=client_myds->fd;
+				fds.events=POLLOUT;
+				fds.revents=0;
+				int retpoll=poll(&fds, 1, 0);
+				if (retpoll>0) {
+					if (fds.revents==POLLOUT) {
+						retbytes=client_myds->write_to_net_poll();
+						if (retbytes==QUEUE_T_DEFAULT_SIZE) { // optimization to solve memory bloat
+							runloop=true;
+						}
+					}
+				}
+			}
 		}
 	}
 	//if (server_myds && server_myds->net_failure==false) server_myds->write_to_net_poll();

src/Makefile

@@ -56,7 +56,8 @@ LDIRS=-L$(LDIR) -L$(JEMALLOC_LDIR) $(LIBCONFIG_LDIR) -L$(RE2_PATH)/obj -L$(LIBEV
 MYCPPFLAGS=-std=c++11 $(IDIRS) $(OPTZ) $(DEBUG)
 LDFLAGS+=
 #LIBS=-rdynamic -Wl,-Bstatic -lconfig -lproxysql -ldaemon -ljemalloc -lconfig++ -lre2 -linjection -levent -lmariadbclient -lprotobuf -Wl,-Bdynamic -lpthread -lm -lz -lrt -ldl -lcrypto -lssl $(EXTRALINK)
-MYLIBS=-Wl,--export-dynamic -Wl,-Bstatic -lconfig -lproxysql -ldaemon -ljemalloc -lconfig++ -lre2 -levent -lmariadbclient -Wl,-Bdynamic -lpthread -lm -lz -lrt -lcrypto -lssl $(EXTRALINK)
+#MYLIBS=-Wl,--export-dynamic -Wl,-Bstatic -lconfig -lproxysql -ldaemon -ljemalloc -lconfig++ -lre2 -levent -lmariadbclient -Wl,-Bdynamic -lpthread -lm -lz -lrt -lcrypto -lssl $(EXTRALINK)
+MYLIBS=-Wl,--export-dynamic -Wl,-Bstatic -lconfig -lproxysql -ldaemon -lconfig++ -lre2 -levent -lmariadbclient -Wl,-Bdynamic -lpthread -lm -lz -lrt -lcrypto -lssl $(EXTRALINK)
 #LIBS=-rdynamic -Wl,-Bstatic -lproxysql -ljemalloc -levent $(GLIB_LIB) -Wl,-Bdynamic -ldl -lpthread -lm -lz -lrt
 
 UNAME_S := $(shell uname -s)

src/main.cpp

@@ -126,7 +126,7 @@ static volatile int load_;
 
 //__thread l_sfp *__thr_sfp=NULL;
 
-const char *malloc_conf = "xmalloc:true,lg_tcache_max:16";
+const char *malloc_conf = "xmalloc:true,lg_tcache_max:16,purge:decay_time";
 //const char *malloc_conf = "prof_leak:true,lg_prof_sample:0,prof_final:true,xmalloc:true,lg_tcache_max:16";
 
 int listen_fd;