Automatic detection of xlC is missing from Autoconf, so a number of variables need to be set before running configure. The following example uses the IBM compiler:

export CC="xlc_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192 "
export CXX="xlC_r -ma -O3 -qstrict -qoptimize=3 -qmaxmem=8192"
export CFLAGS="-I /usr/local/include"
export LDFLAGS="-L /usr/local/lib"
export CPPFLAGS=$CFLAGS
export CXXFLAGS=$CFLAGS

./configure --prefix=/usr/local \
                --localstatedir=/var/mysql \
                --sbindir='/usr/local/bin' \
                --libexecdir='/usr/local/bin' \
                --enable-thread-safe-client \
                --enable-large-files

The preceding options are used to compile the MySQL distribution that can be found at https://www-frec.bull.com/.

If you change the -O3 to -O2 in the preceding configure line, you must also remove the -qstrict option. This is a limitation in the IBM C compiler.

If you are using gcc or egcs to compile MySQL, you must use the -fno-exceptions flag, because the exception handling in gcc/egcs is not thread-safe! (This is tested with egcs 1.1.) There are also some known problems with IBM's assembler that may cause it to generate bad code when used with gcc.

We recommend the following configure line with egcs and gcc 2.95 on AIX:

CC="gcc -pipe -mcpu=power -Wa,-many" \
CXX="gcc -pipe -mcpu=power -Wa,-many" \
CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti" \
./configure --prefix=/usr/local/mysql --with-low-memory

The -Wa,-many option is necessary for the compile to be successful. IBM is aware of this problem but is in no hurry to fix it because of the workaround that is available. We don't know if the -fno-exceptions is required with gcc 2.95, but because MySQL doesn't use exceptions and the option generates faster code, we recommend that you should always use it with egcs / gcc.

If you get a problem with assembler code, try changing the -mcpu=xxx option to match your CPU. Typically power2, power, or powerpc may need to be used. Alternatively, you might need to use 604 or 604e. We are not positive but suspect that power would likely be safe most of the time, even on a power2 machine.

If you don't know what your CPU is, execute a uname -m command. It produces a string that looks like 000514676700, with a format of xxyyyyyymmss where xx and ss are always 00, yyyyyy is a unique system ID and mm is the ID of the CPU Planar. A chart of these values can be found at https://www16.boulder.ibm.com/pseries/en_US/cmds/aixcmds5/uname.htm.

This gives you a machine type and a machine model you can use to determine what type of CPU you have.

If you have problems with signals (MySQL dies unexpectedly under high load), you may have found an OS bug with threads and signals. In this case, you can tell MySQL not to use signals by configuring as follows:

CFLAGS=-DDONT_USE_THR_ALARM CXX=gcc \
CXXFLAGS="-felide-constructors -fno-exceptions -fno-rtti \
-DDONT_USE_THR_ALARM" \
./configure --prefix=/usr/local/mysql --with-debug \
    --with-low-memory

This doesn't affect the performance of MySQL, but has the side effect that you can't kill clients that are “sleeping” on a connection with mysqladmin kill or mysqladmin shutdown. Instead, the client dies when it issues its next command.

On some versions of AIX, linking with libbind.a makes getservbyname() dump core. This is an AIX bug and should be reported to IBM.

For AIX 4.2.1 and gcc, you have to make the following changes.

After configuring, edit config.h and include/my_config.h and change the line that says this:

#define HAVE_SNPRINTF 1

to this:

#undef HAVE_SNPRINTF

And finally, in mysqld.cc, you need to add a prototype for initgroups().

#ifdef _AIX41
extern "C" int initgroups(const char *,int);
#endif

If you need to allocate a lot of memory to the mysqld process, it's not enough to just use ulimit -d unlimited. You may also have to modify mysqld_safe to add a line something like this:

export LDR_CNTRL='MAXDATA=0x80000000'

You can find more information about using a lot of memory at https://publib16.boulder.ibm.com/pseries/en_US/aixprggd/genprogc/lrg_prg_support.htm.

Users of AIX 4.3 should use gmake instead of the make utility included with AIX.