One could define things that way, but it serves very little purpose. Typically, the goal of a test
o is T
is to be allow one to use o as a T by invoking a method on it. If you make this answer true for null, you need to test for null separately, which is painful and error prone. On the other hand, we do allow assignment, because of the general need for placeholder when a useful value is unknown.
Use " sys as sysdba " as user name or supply the internal_logon with the value sysdba in the advanced properties tab. So internal_login is the property name that should be used to mark the current user as a sysdba.
The obligatory disclaimer: The more performance you gain, the more data integrity you loose! But if you want to tune something like a file system, I strongly assume that you know what you are doing :) These tips apply to all major Linux distributions like Fedora/Red Hat, OpenSUSE, and Ubuntu that are already using ext4 or are going to make ext4 their default file system. As write operations on Solid State Disks (SSD) are expensive the tips below are focused on SSD usage but also apply to HDD usage as well . My Ubuntu 9.04 Jaunty /etc/fstab after a fresh installation: [...] UUID=d818ddf9-ff01-e21a-a67d-3ceab43a9e2b / ext4 relatime,errors=remount-ro 0 1 UUID=0d339122-74e0-e0ea-805a-7879b1fa3172 /home ext4 relatime 0 2 [...] My tuned Ubuntu 9.04 Jaunty /etc/fstab : [...] UUID=d818ddf9-ff01-e21a-a67d-3ceab43a9e2b / ext4 noatime,barrier=0,nobh,commit=100,nouser_xattr 0 1 UUID=0d339122-74e0-e0ea-805a-7879b1fa3172 /home ext4 noatime,barrier=0,data=writeback,nobh,commit=100,nouser_xattr 0
Building Chromium, the raw version of Googles state of the art browser Chrome under Linux x64/x86_64 the following error occurred /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.2.4/libstdc++.so when searching for -lstdc++ /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.2.4/libstdc++.a when searching for -lstdc++ /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.2.4/libstdc++.so when searching for -lstdc++ /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.2.4/libstdc++.a when searching for -lstdc++ /usr/bin/ld: cannot find -lstdc++ collect2: ld returned 1 exit status scons: *** [obj/release/mksnapshot] Error 1 scons: *** [/home/alex/Documents/dev/prj/chromium/src/v8/obj/release/mksnapshot] Error 2 scons: building terminated because of errors. as there were no x86 libraries . Installing these libraries solved the problem for me: aptitude install g++-multilib g++-4.2-multilib