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MySQL Reference Manual :: 7.5.4 How Compiling and Linking Affects the Speed of MySQL
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- 7.5 Optimizing the MySQL Server
- 7.5.1 System Factors and Startup Parameter Tuning
- 7.5.2 Tuning Server Parameters
- 7.5.3 Controlling Query Optimizer Performance
- 7.5.4 How Compiling and Linking Affects the Speed of MySQL
- 7.5.5 How MySQL Uses Memory
- 7.5.6 How MySQL Uses DNS
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Most of the following tests were performed on Linux with the MySQL benchmarks, but they should give some indication for other operating systems and workloads.
You get the fastest executables when you link with
-static.
On Linux, you get the fastest code when compiling with
pgcc and -O3. You need about
200MB memory to compile sql_yacc.cc with these
options, because gcc/pgcc needs a lot of memory
to make all functions inline. You should also set
CXX=gcc when configuring MySQL to avoid inclusion
of the libstdc++ library, which is not needed.
Note that with some versions of pgcc, the
resulting code runs only on true Pentium processors, even if you use
the compiler option indicating that you want the resulting code to
work on all x586-type processors (such as AMD).
By just using a better compiler and better compiler options, you can get a 10-30% speed increase in your application. This is particularly important if you compile the MySQL server yourself.
We have tested both the Cygnus CodeFusion and Fujitsu compilers, but when we tested them, neither was sufficiently bug-free to allow MySQL to be compiled with optimizations enabled.
The standard MySQL binary distributions are compiled with support
for all character sets. When you compile MySQL yourself, you should
include support only for the character sets that you are going to
use. This is controlled by the --with-charset
option to configure.
Here is a list of some measurements that we have made:
If you use
pgccand compile everything with-O6, the mysqld server is 1% faster than with gcc 2.95.2.If you link dynamically (without
-static), the result is 13% slower on Linux. Note that you still can use a dynamically linked MySQL library for your client applications. It is the server that is most critical for performance.If you strip your mysqld binary with
strip mysqld, the resulting binary can be up to 4% faster.For a connection from a client to a server running on the same host, if you connect using TCP/IP rather than a Unix socket file, performance is 7.5% slower. (On Unix, if you connect to the hostname
localhost, MySQL uses a socket file by default.)For TCP/IP connections from a client to a server, connecting to a remote server on another host is 8-11% slower than connecting to the local server on the same host, even for connections over 100Mb/s Ethernet.
When running our benchmark tests using secure connections (all data encrypted with internal SSL support) performance was 55% slower than for unencrypted connections.
If you compile with
--with-debug=full, most queries are 20% slower. Some queries may take substantially longer; for example, the MySQL benchmarks ran 35% slower. If you use--with-debug(without=full), the slowdown is only 15%. For a version of mysqld that has been compiled with--with-debug=full, you can disable memory checking at runtime by starting it with the--skip-safemallocoption. The execution speed should then be close to that obtained when configuring with--with-debug.On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4% faster than one compiled with gcc 3.2.
On a Sun UltraSPARC-IIe, a server compiled with Forte 5.0 is 4% faster in 32-bit mode than in 64-bit mode.
Compiling with gcc 2.95.2 for UltraSPARC with the
-mcpu=v8 -Wa,-xarch=v8plusaoptions gives 4% more performance.On Solaris 2.5.1, MIT-pthreads is 8-12% slower than Solaris native threads on a single processor. With more load or CPUs, the difference should be larger.
Compiling on Linux-x86 using gcc without frame pointers (
-fomit-frame-pointeror-fomit-frame-pointer -ffixed-ebp) makes mysqld 1-4% faster.
Binary MySQL distributions for Linux that are provided by MySQL AB
used to be compiled with pgcc. We had to go back
to regular gcc due to a bug in
pgcc that would generate code that does not run
on AMD. We will continue using gcc until that bug
is resolved. In the meantime, if you have a non-AMD machine, you can
get a faster binary by compiling with pgcc. The
standard MySQL Linux binary is linked statically to make it faster
and more portable.
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