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.

2 files changed, 7 insertions, 19 deletions

diff --git a/config/ac-macros/misc.m4 b/config/ac-macros/misc.m4
index ec0c296a8b2..556cc7625cc 100644
--- a/config/ac-macros/misc.m4
+++ b/config/ac-macros/misc.m4
@@ -594,22 +594,13 @@ AC_MSG_RESULT($ac_cv_conv_longlong_to_float)
 ])
 
 AC_DEFUN([MYSQL_CHECK_VIO], [
-  AC_ARG_WITH([vio],
-              [  --with-vio              Include the Virtual IO support],
-              [vio="$withval"],
-              [vio=no])
-
-  if test "$vio" = "yes"
-  then
-    vio_dir="vio"
-    vio_libs="../vio/libvio.la"
-    AC_DEFINE(HAVE_VIO, 1)
-  else
-    vio_dir=""
-    vio_libs=""
-  fi
-  AC_SUBST([vio_dir])
-  AC_SUBST([vio_libs])
+dnl
+dnl we always use vio: no need for special defines 
+dnl
+  AC_DEFINE([HAVE_VIO_READ_BUFF], [1],
+            [Define to enable buffered read. This works only if syscalls
+            read/recv return as soon as there is some data in the kernel
+            buffer, no matter how big the given buffer is.])
 ])
 
 # Local version of _AC_PROG_CXX_EXIT_DECLARATION that does not
diff --git a/config/ac-macros/openssl.m4 b/config/ac-macros/openssl.m4
index 9da0e38f2ba..6541a492247 100644
--- a/config/ac-macros/openssl.m4
+++ b/config/ac-macros/openssl.m4
@@ -89,9 +89,6 @@ AC_MSG_CHECKING(for OpenSSL)
 	fi
     MYSQL_FIND_OPENSSL([$openssl_includes], [$openssl_libs])
     #force VIO use
-    vio_dir="vio"
-    vio_libs="../vio/libvio.la"
-    AC_DEFINE([HAVE_VIO], [1], [Virtual IO])
     AC_MSG_RESULT(yes)
     openssl_libs="-L$OPENSSL_LIB -lssl -lcrypto"
     # Don't set openssl_includes to /usr/include as this gives us a lot of