Windows 95 and threads
Windows 95 leaks about 200 bytes of main memory for each
thread creation. Each connection in MySQL creates a new
thread, so you shouldn't run mysqld for
an extended time on Windows 95 if your server handles many
connections! Newer versions of Windows don't suffer from
Limited number of ports
Windows systems have about 4,000 ports available for client
connections, and after a connection on a port closes, it
takes two to four minutes before the port can be reused. In
situations where clients connect to and disconnect from the
server at a high rate, it is possible for all available
ports to be used up before closed ports become available
again. If this happens, the MySQL server appears to be
unresponsive even though it is running. Note that ports may
be used by other applications running on the machine as
well, in which case the number of ports available to MySQL
For more information about this problem, see
MySQL depends on the
pwrite() system calls to be able to mix
Currently, we use mutexes to emulate
We intend to replace the file level interface with a virtual
interface in the future so that we can use the
interface on NT, 2000, and XP to get more speed. The current
implementation limits the number of open files that MySQL
5.1 can use to 2,048, which means that you
cannot run as many concurrent threads on Windows NT, 2000,
XP, and 2003 as on Unix.
MySQL uses a blocking read for each connection. That has the
following implications if named-pipe connections are
A connection is not disconnected automatically after
eight hours, as happens with the Unix version of MySQL.
If a connection hangs, it is not possible to break it
without killing MySQL.
mysqladmin kill does not work on a
mysqladmin shutdown cannot abort as
long as there are sleeping connections.
We plan to fix this problem in the future.
While you are executing an
statement, the table is locked from being used by other
threads. This has to do with the fact that on Windows, you
can't delete a file that is in use by another thread. In the
future, we may find some way to work around this problem.
DROP TABLE on a table that is in use by a
MERGE table does not work on Windows
MERGE handler does the table
mapping hidden from the upper layer of MySQL. Because
Windows does not allow dropping files that are open, you
first must flush all
MERGE tables (with
FLUSH TABLES) or drop the
MERGE table before dropping the table.
DATA DIRECTORY and
DATA DIRECTORY and
DIRECTORY options for
TABLE are ignored on Windows, because Windows
doesn't support symbolic links. These options also are
ignored on systems that have a non-functional
You cannot drop a database that is in use by some thread.
Killing MySQL from the Task
On Windows 95, you cannot kill MySQL from the Task Manager
or with the shutdown utility. You must stop it with
Filenames are not case sensitive on Windows, so MySQL
database and table names are also not case sensitive on
Windows. The only restriction is that database and table
names must be specified using the same case throughout a
given statement. See
Section 9.2.2, “Identifier Case Sensitivity”.
pathname separator character
Pathname components in Windows are separated by the
\’ character, which is also
the escape character in MySQL. If you are using
LOAD DATA INFILE or
INTO OUTFILE, use Unix-style filenames with
LOAD DATA INFILE 'C:/tmp/skr.txt' INTO TABLE skr;
SELECT * INTO OUTFILE 'C:/tmp/skr.txt' FROM skr;
Alternatively, you must double the
LOAD DATA INFILE 'C:\\tmp\\skr.txt' INTO TABLE skr;
SELECT * INTO OUTFILE 'C:\\tmp\\skr.txt' FROM skr;
Problems with pipes
Pipes do not work reliably from the Windows command-line
prompt. If the pipe includes the character
thinks that it has encountered end-of-file and aborts the
This is mainly a problem when you try to apply a binary log
binary_log_file | mysql --user=root
If you have a problem applying the log and suspect that it
is because of a
CHAR(24) character, you can use the
mysql --user=root --execute "source /tmp/bin.sql"
The latter command also can be used to reliably read in any
SQL file that may contain binary data.
Access denied for
If MySQL cannot resolve your hostname properly, you may get
the following error when you attempt to run a MySQL client
program to connect to a server running on the same machine:
Access denied for user '
to database 'mysql'
To fix this problem, you should create a file named
\windows\hosts containing the following