Porting of "buffered read" patch to 5.0 and post-review fixes.

The patch implements the idea suggested by Olaf van der Spek in 
thread "Client: many small reads?" (internals@lists.mysql.com).
Now small reads performed by the client library are buffered.
The buffering gives up to 2 times speedup when retrieving 
one-column tables.


BUILD/SETUP.sh:
  Remove --with-vio option which no longer exist.
BUILD/compile-pentium64-valgrind-max:
  Remove --with-vio option which no longer exist.
config/ac-macros/misc.m4:
  Removed --with-vio configure switch: we always use VIO. The switch,
   in fact, only saved us one pointer dereferencing per call in case we had
  only one transport type in VIO enabled.
config/ac-macros/openssl.m4:
  Removed HAVE_VIO.
include/config-win.h:
  Removed HAVE_VIO (not needed anymore)
  Added HAVE_VIO_READ_BUFF (define buffered client reads for Windows clients).
include/violite.h:
  Removed HAVE_VIO, as currently VIO is always in use.
  Added declaration for vio_read_buff and related members in struct VIO.
sql-common/client.c:
  Use flags to set up vio read buffering in mysql_real_connect.
sql/mysqld.cc:
  Use flags to disable vio read buffering when creating a server 
  connection.
vio/vio.c:
  Optionally set up vio read buffer when creating a new VIO structure.
vio/viosocket.c:
  Implementation of client-side buffered reads in VIO: the idea 
  is to buffer small reads in a client buffer to save amount of
  syscalls per retrieved result set. The implementation relies
  on the fact that read/recv will return as soon as there is
  some data in the kernel buffer, no matter how big the given
  user's buffer is. To be able to disable it in case recv/read don't
  have such semantics, the new calls are guarded
  with #define HAVE_VIO_READ_BUFF. Currently buffered reading is 
  switched on only for BSD sockets and named pipes, both on Windows
  and UNIXes.

1 files changed, 27 insertions, 18 deletions

diff --git a/vio/vio.c b/vio/vio.c
index ea254e2ed5a..6227493b994 100644
--- a/vio/vio.c
+++ b/vio/vio.c
@@ -27,20 +27,23 @@
  * Helper to fill most of the Vio* with defaults.
  */
 
-void vio_reset(Vio* vio, enum enum_vio_type type,
-		      my_socket sd, HANDLE hPipe,
-		      my_bool localhost)
+static void vio_init(Vio* vio, enum enum_vio_type type,
+                     my_socket sd, HANDLE hPipe, uint flags)
 {
-  DBUG_ENTER("vio_reset");
-  DBUG_PRINT("enter", ("type: %d  sd: %d  localhost: %d", type, sd,
-                       localhost));
+  DBUG_ENTER("vio_init");
+  DBUG_PRINT("enter", ("type: %d  sd: %d  flags: %d", type, sd, flags));
 
+#ifndef HAVE_VIO_READ_BUFF
+  flags&= ~VIO_BUFFERED_READ;
+#endif
   bzero((char*) vio, sizeof(*vio));
   vio->type	= type;
   vio->sd	= sd;
   vio->hPipe	= hPipe;
-  vio->localhost= localhost;
-#ifdef HAVE_VIO  
+  vio->localhost= flags & VIO_LOCALHOST;
+  if ((flags & VIO_BUFFERED_READ) &&
+      !(vio->read_buffer= (char*)my_malloc(VIO_READ_BUFFER_SIZE, MYF(MY_WME))))
+    flags&= ~VIO_BUFFERED_READ;
 #ifdef __WIN__ 
   if (type == VIO_TYPE_NAMEDPIPE)
   {
@@ -101,7 +104,7 @@ void vio_reset(Vio* vio, enum enum_vio_type type,
   {
     vio->viodelete	=vio_delete;
     vio->vioerrno	=vio_errno;
-    vio->read		=vio_read;
+    vio->read= (flags & VIO_BUFFERED_READ) ? vio_read_buff : vio_read;
     vio->write		=vio_write;
     vio->fastsend	=vio_fastsend;
     vio->viokeepalive	=vio_keepalive;
@@ -113,21 +116,30 @@ void vio_reset(Vio* vio, enum enum_vio_type type,
     vio->is_blocking	=vio_is_blocking;
     vio->timeout	=vio_timeout;
   }
-#endif /* HAVE_VIO */
   DBUG_VOID_RETURN;
 }
 
 
+/* Reset initialized VIO to use with another transport type */
+
+void vio_reset(Vio* vio, enum enum_vio_type type,
+               my_socket sd, HANDLE hPipe, uint flags)
+{
+  my_free(vio->read_buffer, MYF(MY_ALLOW_ZERO_PTR));
+  vio_init(vio, type, sd, hPipe, flags);
+}
+
+
 /* Open the socket or TCP/IP connection and read the fnctl() status */
 
-Vio *vio_new(my_socket sd, enum enum_vio_type type, my_bool localhost)
+Vio *vio_new(my_socket sd, enum enum_vio_type type, uint flags)
 {
   Vio *vio;
   DBUG_ENTER("vio_new");
   DBUG_PRINT("enter", ("sd: %d", sd));
   if ((vio = (Vio*) my_malloc(sizeof(*vio),MYF(MY_WME))))
   {
-    vio_reset(vio, type, sd, 0, localhost);
+    vio_init(vio, type, sd, 0, flags);
     sprintf(vio->desc,
 	    (vio->type == VIO_TYPE_SOCKET ? "socket (%d)" : "TCP/IP (%d)"),
 	    vio->sd);
@@ -163,7 +175,7 @@ Vio *vio_new_win32pipe(HANDLE hPipe)
   DBUG_ENTER("vio_new_handle");
   if ((vio = (Vio*) my_malloc(sizeof(Vio),MYF(MY_WME))))
   {
-    vio_reset(vio, VIO_TYPE_NAMEDPIPE, 0, hPipe, TRUE);
+    vio_init(vio, VIO_TYPE_NAMEDPIPE, 0, hPipe, VIO_LOCALHOST);
     strmov(vio->desc, "named pipe");
   }
   DBUG_RETURN(vio);
@@ -179,7 +191,7 @@ Vio *vio_new_win32shared_memory(NET *net,HANDLE handle_file_map, HANDLE handle_m
   DBUG_ENTER("vio_new_win32shared_memory");
   if ((vio = (Vio*) my_malloc(sizeof(Vio),MYF(MY_WME))))
   {
-    vio_reset(vio, VIO_TYPE_SHARED_MEMORY, 0, 0, TRUE);
+    vio_init(vio, VIO_TYPE_SHARED_MEMORY, 0, 0, VIO_LOCALHOST);
     vio->handle_file_map= handle_file_map;
     vio->handle_map= handle_map;
     vio->event_server_wrote= event_server_wrote;
@@ -204,11 +216,8 @@ void vio_delete(Vio* vio)
   if (vio)
   {
     if (vio->type != VIO_CLOSED)
-#ifdef HAVE_VIO /*WAX*/
       vio->vioclose(vio);
-#else
-      vio_close(vio);
-#endif
+    my_free((gptr) vio->read_buffer, MYF(MY_ALLOW_ZERO_PTR));
     my_free((gptr) vio,MYF(0));
   }
 }