Myoddweb.com

Moving your MySQL data from one folder to another sounds like a big job, but in reality it is not really.
Before we get started you need to bear a couple of things in mind

• Be sure to read this entire post before you do anything.
• Especially read the part about the ‘socket’.
• Be sure to understand everything that is in the post
• Some versions of unix/linux use different terminology, (for example to stop/start a service), be sure that you use the correct command.
• Be sure you are logged in as root.
• Remember that there will be down time!
  The length of time depends a lot on the size of the data and where you are transferring to/from.
• Be prepared to roll back the changes if things don’t work!
  • Stop the service.
  • Copy the original my.cnf file, (see below to locate it)
  • Start the service.
• This is all done at your own risk! If you are not careful you could really trash your data!
• Read the errors you might get, learn about your system, normally the error should help you solve most issues.
• Try it on your test/dev server before you do anything, (you have a test server don’t you!!)

Locate the datadir.
This is where MySQL currently has all the data saved, everything is saved in one place.

Run the script, (with phpMyAdmin or something), below and look for the entry that says “datadir”.

# locate the current data directory
SHOW VARIABLES WHERE Variable_Name LIKE “%dir”

Locate the my.cnf.
This is the file that contains the MySQL configuration, this is a very important point and you need to do it carefully.

There could be more than one file so you will need to check all of them!!!

# locate my.cnf, (the very fist line been returned from the cmd below).
# more than one could be given
mysqld –help –verbose

This will return a whole lot of information, but the very first line will contain the locations.

• Not all the files will exist
• Maybe _none_ of the files will exist
• If none exist, create a file called “my.cnf” in the first folder in the list.
• If any of the files exist, look in any of them for the entry “datadir=…”
  (of course making sure it corresponds to the datadir you located in the previous step.

Stop the MySQL service.
This is a typical case where you need to choose the right command for your repo… do your homework first…

service mysql stop
# or maybe
# /etc/init.d/mysql stop

Copy the data from the old folder to the new folder

# copy the data over, (change the directories).
# rm -rf /home/mysql/*
cp -R -p /var/lib/mysql /home/mysql

You must learn what this means, “cp -R -p” means, copy the data from the source folder to the destination folder, (“/var/lib/mysql” and “/home/mysql” in my case).

But what this also does is keep the permissions of the folder, normally a user “mysql” is created and has full permissions to that folder.

For things to keep working, you must make sure that the permissions remain.

Spend a bit of time making sure that …

• All the files were copied
• All the permissions have been kept.

Edit the datadir.
In the my.cnf that you edited/created earlier change, (or add), the datadir.

[mysqld]
datadir=/home/mysql
#innodb_data_home_dir
#innodb_log_group_home_dir=/home/mysql/

• There could be other values, only edit/add the datadir=, don’t change anything else!
• In your first step, where you located the directory, look for …
  • innodb_data_home_dir=, if the directory is the same/similar to the one you just moved, then either add an entry or edit the one that is there with the same folder.
  • innodb_log_group_home_dir=, same as above.

Start the MySQL service.

service mysql start
# or maybe
# /etc/init.d/mysql start

Immediately make sure that the server is up and running

mysqladmin status
# or using phpmyadmin# or using whatever tool you fancy…

If it is running ok, make sure that the directories are indeed valid, (same step as earlier).

# locate the current data directory
SHOW VARIABLES WHERE Variable_Name LIKE “%dir”

If the server is not started you might get a ‘socket’ error, in that case, look for where MySQL thinks it is…

SHOW VARIABLES WHERE Variable_name = “socket”

It might point to the old directory, in that case you need to edit the config one more time.

But first stop the service…

service mysql stop
# or maybe
# /etc/init.d/mysql stop

Add two socket section, (one for the client and one for mysql itself)

[client]
# …
socket=/home/mysql/mysql.sock

[mysqld]
# …
socket=/home/mysql/mysql.sock

Of course, in my example, I am using my directory and I am only showing what needs to be edited/added.

Restart the service…

service mysql start
# or maybe
# /etc/init.d/mysql start

And make sure that it is all good!

Delete the old data

If everything is working I would suggest that you back up the old data somewhere else.

To make really sure that all us good, simply rename the old folder, (don’t move it or anything, just rename), and make sure that things are working).

When I was working on the next version of Piger I would sometime get an issue when using the this.bye command, (to close Piger).

What happens in the background is I call WM_CLOSE to close the active window, this message is sent to all the windows.

When it is processed by the message pump no other messages are been processed, this is a problem in case some windows are still dishing out messages, (like a fading dialog box in our example).

So remember, once you call WM_CLOSE, all bets are off and your message pump is as good as dead.

Best to have your own ‘Close()’ that does all the housekeeping in the background before you actually post WM_CLOSE to the main thread…

Otherwise your app my appear to hang.

I was looking at a defect in Piger where a Python script could close Piger itself, it wasn’t a crash, but rather a graceful exit.

import am
am.say( "Bye", 1, 1 );
exit(1);

The problem was with the way I was calling the script rather than anything wrong with Piger or Python itself.

Somewhere in the Python virtual machine I had something like…

...
if( -1 == PyRun_SimpleString( ... ) )
{
...
}
...


And, while that works fine in most cases, if I have an exit( xyz ) in my script, piger would close.
So the answer was to replace it with …


...
PyObject * PyRes = PyRun_String(s, Py_file_input, main_dict, main_dict);
PyObject* ex = PyErr_Occurred();
if( NULL != ex)
{
...
}
...


The one last problem was, how to tell if the error was because of an exit(…) or because of an error.


...
PyObject * PyRes = PyRun_String(s, Py_file_input, main_dict, main_dict);
PyObject* ex = PyErr_Occurred();
if( NULL != ex)
{
// if we exit(...) then 'ex' is not NULL, so we must check for that.
if (!PyErr_ExceptionMatches(PyExc_SystemExit))
{
// this is a real coding error.
}
}
...


Now you can catch all the real errors and swallow all the exist code and so on.

See the exceptions handling in Python and embedding in general.

For my Piger application, I wanted my C++ app to parse Python scripts but I quickly became aware of the fact that the user must have Python installed on their machine, not only that they needed the same version as mine, (version 3.5).

The normal call would be something like…

But that throws an error when the user does not have Python installed.
And if they have an older version installed, it _might_ work, but the scripts might not work as expected.

The solution is to embed the Python you want to run in your app.

1. Go to the Python website and download the Embeddable zip file for your app, (x64 or x86)
2. Extract the python35.zip located inside that zip file
3. Copy it somewhere where it can be referenced.
4. Add the code below.

Now your app will work using version Python 3.5.1

The steps below are for installing C++ on eclipse and window.

I am using Eclipse 4.5 and Windows 10, but it doesn’t really mater, it should work for any version.

• First things first, close everything, whatever version of Eclipse you have open.
  To make your life easier, close things you do not need as well, like notepads and so on.

MinGW

• Go to mingw and download it, (MinGW stands for Minimalist GNU for Windows).
  The version I got was version 0.6.2
  Go to the website, (link above), and click on the “Download Installer” button, (it is not obvious at first where the button is).
• Run the install as an Administrator.
  Pay attention to the install folder, (For me the default was C:\MinGW).
• Wait for the install to complete …
• …
• When this is all done, add the ‘bin’ folder to your PATH environment variable, (Google how to do it), in my case I added “C:\MinGW\bin” to the PATH.
• Open a command line window and type ‘mingw-get install gcc g++ gdb mingw32-make‘.
• Wait for the install to complete …
• …
• Check that everything will work type “gcc –version“, if you get an error, something went wrong.
  Otherwise you should see the gcc version number.

Eclipse

• Open your version of Eclipse
• Go to Help > Eclipse Marketplace …
• Type C++ and select the CDT option
• or add “http://download.eclipse.org/tools/cdt/builds/mars/milestones” as a software site and select CDT main features.
• Download and Update everything.

Others

• Make sure that the right tool chain is selected
  • Project > Properties …
  • C/C++ Build
  • Tool Chain Editor and select “MinGW GCC”

To include Google test to your visual studio project you just need to follow the steps below

1. Download Googletest from Github and copy all the file in it’s own folder.
   You only need the folder called “googletest” other files are for github and so on.
2. Create a library
   1. Add a new empty project
      Right click the solution, Add > New Project …, “Win 32 project”
   2. Give it a name “googletest”
   3. Make sure that the directory is relative to your project, (the default is somewhere weird and wonderful in your %appdata% I think).
   4. Select the option “Static Library”, “empty project” and it should have no files in it.
   5. Uncheck the “Precompiled header” and press “Finish”
   6. Add gtest_main.cc and gtest-all.cc to that project, (they are located in the googletest\src\ folder of the files you just downloaded.
   7. Compile that project, and note where the googletest.lib file is created.
3. In your test project,
   1. Right click > Properties > C++ > General
   2. In the part for “Additional include libraries” add the path to the google test folder and include folder.
      For example, “..\googletest\include;..\googletest\”.
   3. There might already be a folder called “%(AdditionalIncludeDirectories)”.
   4. Right click > Properties > Linker > General
   5. In the part for “”Additional Library directories” add the directory where the googletest.lib file was created, (the library, not the file).
   6. Finaly, add a reference, (Right Click the project > References and add googletest).

Be sure to set the references and include libraries for all your configurations, “Release”, “Debug”, x32, x64 and so on.

NB: Of course you can just build the lib and include it as a library, but that way when Googletest does an update, you just need to replace the code, and life is good again!

Myoddweb email classifier is a Naive Bayes classifier, in very simple terms, it classifies emails based on your previous classifications.

In other words, the more you classify something, the better it is at classifying emails.

So, out of the box, Myoddweb classifier cannot classify anything, you need to teach it what to do.

The classification is also called “Training”, you are training your engine where emails should go to, or, in what category they should be moved to.

Categories

A category is where the emails should be moved to, you could have a category for “Spam”, “Personal” or “Work”.

You should create as many categories as you need, maybe 5 or 6, and then select emails and ‘classify’ them to each categories.

If you selected your categories properly, the emails will slowly start to be automatically classified as they arrive.

Magnets

Magnets help the engine to classify emails, for example, you know that emails from your wife, (from her email address), must all go to the ‘Personal’ category.
When the engine receives such an email, it will automatically flag it as “Personal” and learn from its contents.

To install Myoddweb classifier simply follow the following steps

• Download the setup from Github (will open new window).
• Make sure that Outlook is closed.
• Make sure that you have .NET version 4.5 or later (will open new window).
• Run the setup
  Depending on the version on windows you are using you will get a ‘warning’ asking you to confirm if you want to install the app.
• Start Outlook

After the install is complete nothing will really look any different.

This is because you will need to ‘train’ your classifier to match your own requirements.

The other day I upgraded my dev box to php 5.3.6, (from 5.2.x), and I got frustrated because I could not get php_mycrypt.dll to load.

The reason is simply because it is bundled in php 5.3.x, (for windows at least).
I suspect it is also built in with the unix versions as well.

1- You see code instead of the script been run

Locate the file called httpd.conf and make sure you have something like
…
PHPIniDir “C:/Program Files (x86)/php”
AddType application/x-httpd-php .php .php5
LoadModule php5_module “C:/Program Files (x86)/php/php5apache2_2.dll”
…

And restart the Apache server

2- httpd.conf is either located in

C:\Program Files (x86)\Apache Software Foundation\Apache2.2\
or
C:\Program Files (x86)\Apache Software Foundation\Apache2.2\conf

I’ll add more later as I think of them…