[PL/SQL] existing state of package has been invalidated error

After compiling Oracle packages, it is possible to get a "existing state of packages has been discarded" or "existing state of package has been invalidated" error.

The cause is usually a global variable or constant declared in the package or package body that is re-initialized after the compilation action. The error is thrown to avoid having programs read the wrong state (variable/constant) of the package.

The easiest way to solve this issue is to simply disconnect the session and reconnect.

[TOAD] Oracle explain plan error looping chain of synonyms - fix

TOAD is a powerful client for Oracle DB, although I have to admit SQLDeveloper is not that bad either (and it's also free).

Sometimes while trying to get an explain plan, the error "ORA-01775 - looping chain of synonyms" might occur.

The fix is quite easy: from the options menu go to the Oracle - General section and find the Table field. The value there should be PLAN_TABLE rather than TOAD_PLAN_TABLE.

Save settings, restart TOAD and you're set

[Ubuntu] fix plymouthd splash load boot error

We sometimes struggle to keep up with all the things that are constantly evolving, so I like how Ubuntu still gives us reassurances that some important features are cemented in its core, such as the plymouthd boot splash error: "plymouthd could not load boot splash: could not access needed shared library".

Just update the kernel and you might be the lucky winner that gets stuck at boot.

The fix is easy and fast enough though. The immediate thing you can try is to edit the boot options when GRUB presents you the list of boot choices:

1. select the Ubuntu line corresponding to the kernel you want to boot and press the e key
2. find the line where the ro quiet splash parameters are set (unless you have already changed them in the past), but then you know which line I'm talking about anyway ;)
3. remove the splash parameter
4. add at the end of the line: gfxpayload=keep
5. press F10 to boot

[Linux] Connect Android phone for file transfer

One of the things I like about Android, is the ease with which you can connect your device to any computer and start transferring files right away. Recent versions of the OS however are using MTP to perform the exchanges.

On some Linux distros, this means you need to install additional packages to keep using your phone as you prefer:

mtp-tools mtpfs

After installation, the phone should be accessible via your file manager

[LXDE] LUbuntu desktop composition enable key shortcuts

The openbox window manager bundled with LUbuntu is powerful enough to provide the same functionality as similar applications, but it's unfortunately delivered with a barebone configuration.

One functionality I'm missing it's the ability to drag, resize and snap windows to desktop sides. Luckily I found code pieces to enable such functionality, albeit not via mouse controls but key combinations; to add it, simply edit ~/.config/openbox/lubuntu-rc.xml and add under the line

 <chainQuitKey>C-g</chainQuitKey>  

this code:

 <keybind key="W-Left">    # HalfLeftScreen  
  <action name="UnmaximizeFull"/>  
  <action name="MoveResizeTo">  
   <x>0</x>  
   <y>0</y>  
   <height>100%</height>  
   <width>50%</width>  
  </action>  
 </keybind>  
 <keybind key="W-Right">    # HalfRightScreen  
  <action name="UnmaximizeFull"/>  
  <action name="MoveResizeTo">  
   <x>-0</x>  
   <y>0</y>  
   <height>100%</height>  
   <width>50%</width>  
  </action>  
 </keybind>  

Then just do an openbox --restart

You can now use the Windows key (Super) and the right or left arrow to snap the currently active window to the right or left side of the screen, at 50% width

Note: apparently openbox is reserving some space for the toolbar on the bottom of the screen, so even declaring 100% height will NOT fill all available space after resizing.

[xterm] Edit appearance and store preferences

It's possible to edit the xterm console appearance and permanently store the changes by creating or editing the ~/.Xresources file. You can find the full list of settings on the man page, here are some useful ones:

XTerm*Background: white
XTerm*Foreground: black
XTerm*geometry: 140x45

The code above will set the default window size to 140x45 and display black characters on white background.

To apply the settings to all future xterm consoles, even after a reboot, just run once:

xrdb -merge ~/.Xresources

and finally restart xterm

[Kodi] Crash on exit bug fix

I was trying out Kodi, specifically the Kodibuntu version they provide, aka: Kodi installed on a quite barebone LUbuntu, and I must say I'm really impressed. Outputting 5.1 audio over SPDIF and watching HD movies is made very easy and works out of the box.

There is however one interesting bug that comes in various forms and basically causes Kodi to crash or freeze everytime you try to quit it.

The fix is very simple as the issue seems to be caused by the Version check addon; disabling it is sufficient to solve the problem.