Bug #425, http://bugs.skysql.com/show_bug.cgi?id=425

mysqlk_client.c now assumes that mysql packets may arrive in separate pieces.
gw_read_client_event reads client data, and if packet is incomplete it is added to new dcb->dcb_readqueue. When next packet is combined with data in readqueue.

mysql_common.c:gw_MySQL_get_next_packet can now return mysql packet from read buffer although it would span multiple gwbuf buffers.

server/core/dcb.c

@@ -117,6 +117,7 @@ DCB	*rval;
         spinlock_init(&rval->dcb_initlock);
 	spinlock_init(&rval->writeqlock);
 	spinlock_init(&rval->delayqlock);
+        spinlock_init(&rval->dcb_readqlock);
 	spinlock_init(&rval->authlock);
         rval->fd = -1;
 	memset(&rval->stats, 0, sizeof(DCBSTATS));	// Zero the statistics
@@ -302,12 +303,17 @@ dcb_final_free(DCB *dcb)
 	if (dcb->remote)
 		free(dcb->remote);
 
-	/* Consume dcb->delayq buffer */	
+	/* Clear write and read buffers */	
 	if (dcb->delayq) {
 		GWBUF *queue = dcb->delayq;
 		while ((queue = gwbuf_consume(queue, GWBUF_LENGTH(queue))) != NULL);
 	}
 
+	if (dcb->dcb_readqueue)
+        {
+                GWBUF* queue = dcb->dcb_readqueue;
+                while ((queue = gwbuf_consume(queue, GWBUF_LENGTH(queue))) != NULL);
+        }
 	bitmask_free(&dcb->memdata.bitmask);
         simple_mutex_done(&dcb->dcb_read_lock);
         simple_mutex_done(&dcb->dcb_write_lock);

server/include/dcb.h

@@ -176,6 +176,8 @@ typedef struct dcb {
 	GWBUF		*writeq;	/**< Write Data Queue */
 	SPINLOCK	delayqlock;	/**< Delay Backend Write Queue spinlock */
 	GWBUF		*delayq;	/**< Delay Backend Write Data Queue */
+	GWBUF           *dcb_readqueue; /**< read queue for storing incomplete reads */
+	SPINLOCK        dcb_readqlock;  /**< read/write access protection to read queue */
 	SPINLOCK	authlock;	/**< Generic Authorization spinlock */
 
 	DCBSTATS	stats;		/**< DCB related statistics */

server/modules/include/mysql_client_server_protocol.h

@@ -304,4 +304,5 @@ char *gw_strend(register const char *s);
 int  setnonblocking(int fd);
 int	setipaddress(struct in_addr *a, char *p);
 int  gw_read_gwbuff(DCB *dcb, GWBUF **head, int b);
-GWBUF* gw_MySQL_get_next_stmt(GWBUF** p_readbuf);
+GWBUF* gw_MySQL_get_next_packet(GWBUF** p_readbuf);
+

server/modules/protocol/mysql_client.c

@@ -507,9 +507,11 @@ int gw_read_client_event(DCB* dcb) {
 	ROUTER         *router_instance = NULL;
 	void           *rsession = NULL;
 	MySQLProtocol  *protocol = NULL;
+        GWBUF          *read_buffer = NULL;
 	int             b = -1;
         int             rc = 0;
-
+        int             nbytes_read = 0;
+        
         CHK_DCB(dcb);
         protocol = DCB_PROTOCOL(dcb, MySQLProtocol);
         CHK_PROTOCOL(protocol);
@@ -536,7 +538,6 @@ int gw_read_client_event(DCB* dcb) {
 	/*
 	 * Handle the closed client socket.
 	 */
-
 	if (b == 0) {
 		char c;
 		int l_errno = 0;
@@ -562,40 +563,83 @@ int gw_read_client_event(DCB* dcb) {
 		goto return_rc;
 	}
 
+	rc = gw_read_gwbuff(dcb, &read_buffer, b); 
+        
+        if (rc != 0) {
+                goto return_rc;
+        }
+        
+        nbytes_read = gwbuf_length(read_buffer);
+        ss_dassert(nbytes_read > 0);
+        
+        /** 
+         * if read queue existed appent read to it.
+         *   if length of read buffer is less than 3 or less than mysql packet
+         *   then return.
+         *   else copy mysql packets to separate buffers from read buffer and 
+         *   continue.
+         * else
+         *   if read queue didn't exist, length of read is less than 3 or less 
+         *   than mysql packet then 
+         *   create read queue and append to it and return.
+         *   if length read is less than mysql packet length append to read queue
+         *     append to it and return.
+         *   else (complete packet was read) continue.
+         */
+        if (dcb->dcb_readqueue)
+        {
+                uint8_t* data = (uint8_t *)GWBUF_DATA(read_buffer);
+                
+                read_buffer = gwbuf_append(dcb->dcb_readqueue, read_buffer);
+                nbytes_read = gwbuf_length(read_buffer);
+                
+                if (nbytes_read < 3 || nbytes_read < MYSQL_GET_PACKET_LEN(data))
+                {
+                       rc = 0;
+                       goto return_rc;
+                }
+                else
+                {
+                        /** 
+                         * There is at least one complete mysql packet read 
+                         */
+                        read_buffer = dcb->dcb_readqueue;
+                        dcb->dcb_readqueue = NULL;                        
+                }
+        }
+        else
+        {
+                uint8_t* data = (uint8_t *)GWBUF_DATA(read_buffer);
+                size_t   packetlen = MYSQL_GET_PACKET_LEN(data)+4;
+
+                if (nbytes_read < 3 || nbytes_read < packetlen) 
+                {
+                        gwbuf_append(dcb->dcb_readqueue, read_buffer);
+                        rc = 0;
+                        goto return_rc;
+                }
+        }
+        ss_dassert(nbytes_read >= MYSQL_GET_PACKET_LEN((uint8_t *)GWBUF_DATA(read_buffer))+4);
+        ss_dassert(nbytes_read == MYSQL_GET_PACKET_LEN((uint8_t *)GWBUF_DATA(read_buffer))+4 || 
+                        dcb->dcb_readqueue != NULL);
+        
+        /**
+         * Now there should be at least one complete mysql packet in read_buffer.
+         */
 	switch (protocol->state) {
+                
         case MYSQL_AUTH_SENT:
                 /*
                  * Read all the data that is available into a chain of buffers
                  */
         {
-                int    len = -1;
-                GWBUF *queue = NULL;
-                GWBUF *gw_buffer = NULL;
                 int    auth_val = -1;
-                //////////////////////////////////////////////////////
+                                
-                // read and handle errors & close, or return if busy
+                auth_val = gw_mysql_do_authentication(dcb, read_buffer);
-                // note: if b == 0 error handling is not
-                // triggered, just return
-                // without closing
-                //////////////////////////////////////////////////////
-                rc = gw_read_gwbuff(dcb, &gw_buffer, b); 
-                
-                if (rc != 0) {
-                        goto return_rc;
-                }
-                
-                // example with consume, assuming one buffer only ...
-                queue = gw_buffer;
-                len = GWBUF_LENGTH(queue);
-
-		ss_dassert(len > 0);
-
-                auth_val = gw_mysql_do_authentication(dcb, queue);
-
                 // Data handled withot the dcb->func.write
                 // so consume it now
                 // be sure to consume it all
-                queue = gwbuf_consume(queue, len);
+                read_buffer = gwbuf_consume(read_buffer, nbytes_read);
                 
                 if (auth_val == 0)
                 {
@@ -638,9 +682,7 @@ int gw_read_client_event(DCB* dcb) {
                  * Read all the data that is available into a chain of buffers
                  */
         {
-                int      len = -1;
                 uint8_t  cap = 0;
-                GWBUF   *read_buffer = NULL;
                 uint8_t *ptr_buff = NULL;
                 int      mysql_command = -1;
                 bool     stmt_input; /*< router input type */
@@ -655,22 +697,14 @@ int gw_read_client_event(DCB* dcb) {
                                 session->service->router_instance;
                         rsession = session->router_session;
                 }
-                
+
-                //////////////////////////////////////////////////////
-                // read and handle errors & close, or return if busy
-                //////////////////////////////////////////////////////
-                rc = gw_read_gwbuff(dcb, &read_buffer, b); 
-                
-                if (rc != 0) {
-                        goto return_rc;
-                }
                 /* Now, we are assuming in the first buffer there is
                  * the information form mysql command */
-                len = GWBUF_LENGTH(read_buffer);
                 ptr_buff = GWBUF_DATA(read_buffer);
                 
                 /* get mysql commang at fifth byte */
                 if (ptr_buff) {
+                        ss_dassert(nbytes_read >= 5);
                         mysql_command = ptr_buff[4];
                 }                
                 /**
@@ -701,7 +735,7 @@ int gw_read_client_event(DCB* dcb) {
                         }
                         rc = 1;
                         /** Free buffer */
-                        read_buffer = gwbuf_consume(read_buffer, len);                
+                        read_buffer = gwbuf_consume(read_buffer, nbytes_read);                
                         goto return_rc;
                 }
                 /** Ask what type of input the router expects */
@@ -762,7 +796,12 @@ int gw_read_client_event(DCB* dcb) {
                                 rc = route_by_statement(router_instance,
                                                         router,
                                                         rsession,
-                                                        read_buffer);       
+                                                        read_buffer);
+                                if (read_buffer != NULL)
+                                {
+                                        /** add incomplete mysql packet to read queue */
+                                        gwbuf_append(dcb->dcb_readqueue, read_buffer);
+                                }
                         }
                         else
                         {
@@ -1353,6 +1392,10 @@ return_rc:
  * Detect if buffer includes partial mysql packet or multiple packets.
  * Store partial packet to pendingqueue. Send complete packets one by one
  * to router.
+ * 
+ * It is assumed readbuf includes at least one complete packet. 
+ * Return 1 in success. If the last packet is incomplete return success but
+ * leave incomplete packet to readbuf.
  */
 static int route_by_statement(
         ROUTER*         router_instance, 
@@ -1361,26 +1404,26 @@ static int route_by_statement(
         GWBUF*          readbuf)
 {
         int            rc = -1;
-        DCB*           master_dcb;
+        GWBUF*         packetbuf;
-        GWBUF*         stmtbuf;
-        uint8_t*       payload;
-        static size_t  len;
         
         do 
         {
-                stmtbuf = gw_MySQL_get_next_stmt(&readbuf);
+                packetbuf = gw_MySQL_get_next_packet(&readbuf);
-                ss_dassert(stmtbuf != NULL);
+
-                CHK_GWBUF(stmtbuf);
+                if (packetbuf != NULL)
-                
+                {
-                payload = (uint8_t *)GWBUF_DATA(stmtbuf);
+                        CHK_GWBUF(packetbuf);
-                /**
+                        rc = router->routeQuery(router_instance, rsession, packetbuf);
-                 * If message is longer than read data, suspend routing and
+                }
-                 * add statement buffer to wait queue.
+                else
-                 */
+                {
-                rc = router->routeQuery(router_instance, rsession, stmtbuf);
+                        rc = 1;
+                        goto return_rc;
+                }
         }
         while (readbuf != NULL);
         
+return_rc:
         return rc;
 }
 

server/modules/protocol/mysql_common.c

@@ -1279,54 +1279,86 @@ mysql_send_auth_error (DCB *dcb, int packet_number, int in_affected_rows, const
 
 
 /**
- * Remove the first mysql statement from buffer. Return pointer to the removed
+ * Buffer contains at least one of the following:
- * statement or NULL if buffer is empty.
+ * complete [complete] [partial] mysql packet
- * 
- * Clone buf, calculate the length of included mysql stmt, and point the 
- * statement with cloned buffer. Move the start pointer of buf accordingly
- * so that it only cover the remaining buffer.
  * 
+ * return pointer to gwbuf containing a complete packet or
+ *   NULL if no complete packet was found.
  */
-GWBUF* gw_MySQL_get_next_stmt(
+GWBUF* gw_MySQL_get_next_packet(
         GWBUF** p_readbuf)
 {
-        GWBUF*         stmtbuf;
+        GWBUF*   packetbuf;
-        size_t         buflen;
+        GWBUF*   readbuf;
-        size_t         strlen;
+        size_t   buflen;
-        uint8_t*       packet;
+        size_t   packetlen;
+        size_t   totalbuflen;
+        uint8_t* data;
         
-        if (*p_readbuf == NULL)
+        readbuf = *p_readbuf;
+        
+        if (readbuf == NULL)
         {
-                stmtbuf = NULL;
+                packetbuf = NULL;
-                goto return_stmtbuf;
+                goto return_packetbuf;
         }                
-        CHK_GWBUF(*p_readbuf);
+        CHK_GWBUF(readbuf);
         
-        if (GWBUF_EMPTY(*p_readbuf))
+        if (GWBUF_EMPTY(readbuf))
         {
-                stmtbuf = NULL;
+                packetbuf = NULL;
-                goto return_stmtbuf;
+                goto return_packetbuf;
         }
-        buflen = GWBUF_LENGTH((*p_readbuf));
+        
-        packet = GWBUF_DATA((*p_readbuf));
+        buflen      = GWBUF_LENGTH((readbuf));
-        strlen = MYSQL_GET_PACKET_LEN(packet);
+        totalbuflen = gwbuf_length(readbuf);
+        data        = (uint8_t *)GWBUF_DATA((readbuf));
+        packetlen   = MYSQL_GET_PACKET_LEN(data)+4;
 
-        if (strlen+4 == buflen)
+        /** packet is incomplete */
+        if (packetlen > totalbuflen)
         {
-                stmtbuf = *p_readbuf;
+                packetbuf = NULL;
-                *p_readbuf = NULL;
+                goto return_packetbuf;
-                goto return_stmtbuf;
         }
-        /** vraa :Multi-packet stmt is not supported as of 7.3.14 */
+                
-        if (strlen-1 > buflen-5)
+        if (packetlen == buflen)
         {
-                stmtbuf = NULL;
+                packetbuf = gwbuf_clone_portion(readbuf, 0, packetlen);
-                goto return_stmtbuf;
+                *p_readbuf = gwbuf_consume(readbuf, packetlen);
+                goto return_packetbuf;
+        }
+        /**
+         * Packet spans multiple buffers. 
+         * Allocate buffer for complete packet
+         * copy packet parts into it and consume copied bytes
+         */        
+        else if (packetlen > buflen)
+        {
+                size_t   nbytes_copied = 0;
+                uint8_t* target;
+                
+                packetbuf = gwbuf_alloc(packetlen);
+                target    = GWBUF_DATA(packetbuf);
+
+                while (nbytes_copied < packetlen)
+                {
+                        uint8_t* src = GWBUF_DATA(readbuf);
+                        size_t   buflen = GWBUF_LENGTH(readbuf);
+
+                        memcpy(target+nbytes_copied, src, buflen);
+                        *p_readbuf = gwbuf_consume(readbuf, buflen);
+                        nbytes_copied += buflen;
+                }
+                ss_dassert(nbytes_copied == packetlen);
+        }
+        else
+        {
+                packetbuf = gwbuf_clone_portion(readbuf, 0, packetlen);
+                *p_readbuf = gwbuf_consume(readbuf, packetlen);
         }
-        stmtbuf = gwbuf_clone_portion(*p_readbuf, 0, strlen+4);
-        *p_readbuf = gwbuf_consume(*p_readbuf, strlen+4);
         
-return_stmtbuf:
+return_packetbuf:
-        return stmtbuf;
+        return packetbuf;
 }
 

server/modules/routing/readwritesplit/readwritesplit.c

@@ -547,19 +547,12 @@ static void freeSession(
 }
 
 /**
- * The main routing entry, this is called with every packet that is
+ * It is assumed that whole query comes in a single gwbuf instead of linked list.
- * received and has to be forwarded to the backend database.
+ *  
  *
- * The routeQuery will make the routing decision based on the contents
+ * @param instance	        The router instance
- * of the instance, session and the query itself in the queue. The
+ * @param router_session	The session associated with the client
- * data in the queue may not represent a complete query, it represents
+ * @param querybuf		Gateway buffer queue with the packets received
- * the data that has been received. The query router itself is responsible
- * for buffering the partial query, a later call to the query router will
- * contain the remainder, or part thereof of the query.
- *
- * @param instance	The query router instance
- * @param session	The session associated with the client
- * @param queue		Gateway buffer queue with the packets received
  *
  * @return The number of queries forwarded
  */
@@ -580,12 +573,7 @@ static int routeQuery(
         ROUTER_INSTANCE*   inst = (ROUTER_INSTANCE *)instance;
         ROUTER_CLIENT_SES* router_cli_ses = (ROUTER_CLIENT_SES *)router_session;
         bool               rses_is_closed;
-	rses_property_t*   prop;
         size_t             len;
-        /** if false everything goes to master and session commands to slave too */
-        static bool        autocommit_enabled = true; 
-        /** if true everything goes to master and session commands to slave too */
-        static bool        transaction_active = false;
 
         CHK_CLIENT_RSES(router_cli_ses);
 
@@ -737,9 +725,7 @@ static int routeQuery(
         }
         else if (QUERY_IS_TYPE(qtype, QUERY_TYPE_READ) && 
                 !router_cli_ses->rses_transaction_active)
-        {
+        {               
-                bool succp;
-                
                 LOGIF(LT, (skygw_log_write(
                         LOGFILE_TRACE,
                         "Read-only query, routing to Slave.")));
@@ -751,9 +737,7 @@ static int routeQuery(
                 goto return_ret;
         }
         else
-        {
+        {               
-                bool succp = true;
-                
                 if (LOG_IS_ENABLED(LOGFILE_TRACE))
                 {
                         if (router_cli_ses->rses_transaction_active) /*< all to master */