If you are using Irix 6.5.3 or newer, mysqld is able to create threads only if you run it as a user that has CAP_SCHED_MGT privileges (such as root) or if you give the mysqld server this privilege with the following shell command:

chcap "CAP_SCHED_MGT+epi" /opt/mysql/libexec/mysqld

You may have to undefine some symbols in config.h after running configure and before compiling.

In some Irix implementations, the alloca() function is broken. If the mysqld server dies on some SELECT statements, remove the lines from config.h that define HAVE_ALLOC and HAVE_ALLOCA_H. If mysqladmin create does not work, remove the line from config.h that defines HAVE_READDIR_R. You may have to remove the HAVE_TERM_H line as well.

SGI recommends that you install all the patches on this page as a set:

http://support.sgi.com/surfzone/patches/patchset/6.2_indigo.rps.html

At the very minimum, you should install the latest kernel rollup, the latest rld rollup, and the latest libc rollup.

You definitely need all the POSIX patches on this page, for pthreads support:

http://support.sgi.com/surfzone/patches/patchset/6.2_posix.rps.html

If you get the something like the following error when compiling mysql.cc:

"/usr/include/curses.h", line 82: error(1084):
invalid combination of type

Type the following in the top-level directory of your MySQL source tree:

extra/replace bool curses_bool < /usr/include/curses.h > include/curses.h
make

There have also been reports of scheduling problems. If only one thread is running, performance is slow. Avoid this by starting another client. This may lead to a two-to-tenfold increase in execution speed thereafter for the other thread. This is a poorly understood problem with Irix threads; you may have to improvise to find solutions until this can be fixed.

If you are compiling with gcc, you can use the following configure command:

CC=gcc CXX=gcc CXXFLAGS=-O3 \
./configure --prefix=/usr/local/mysql --enable-thread-safe-client \
    --with-named-thread-libs=-lpthread

On Irix 6.5.11 with native Irix C and C++ compilers ver. 7.3.1.2, the following is reported to work

CC=cc CXX=CC CFLAGS='-O3 -n32 -TARG:platform=IP22 -I/usr/local/include \
-L/usr/local/lib' CXXFLAGS='-O3 -n32 -TARG:platform=IP22 \
-I/usr/local/include -L/usr/local/lib' \
./configure --prefix=/usr/local/mysql --with-innodb --with-berkeley-db \
    --with-libwrap=/usr/local \
    --with-named-curses-libs=/usr/local/lib/libncurses.a