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Thursday, July 24, 2008

Building MySQL from Source: There's a fine line...


There's a fine line between love and hate, you see

Can't wait to late, but baby I'm on it


(From: "Liberation" by Outkast)

Suppose you need to build a MySQL server with the same options as a pre-built one, distributed through the MySQL download site.

Sounds strange?

Well, maybe, but that's what you need if you want to compile certain MySQL 5.1 plug-ins so that they'll will play nice with such a pre-built server.

Some plug-ins depend on nothing more but the plugin.h header file, but for example storage engine plug-ins require things way beyond that. If you want to compile those yourself, you are required to first build a MySQL server from source, even though you will install the plug-in in another, pre-built, server.

(If you want to see how this works in practice, check out the excellent documentation for building and installing the PBXT storage engine plug-in.)

Now, the snag is, the server you need to build must ideally be built in exactly the same way as the deployment server. So, the question is, how do you find out how your server was built?

As it turns out, there is a very simple method to obtain the original compile line. You can find it in the mysqlbug script. On line 28 you see the following line:

CONFIGURE_LINE="./configure '--prefix=/usr/local/mysql' '--localstatedir=/usr/local/mysql/data' '--libexecdir=/usr/local/mysql/bin' '--with-comment=MySQL Community Server (GPL)' '--with-server-suffix=' '--enable-thread-safe-client' '--enable-local-infile' '--enable-assembler' '--with-pic' '--with-fast-mutexes' '--with-client-ldflags=-static' '--with-mysqld-ldflags=-static' '--with-zlib-dir=bundled' '--with-big-tables' '--with-ssl' '--with-readline' '--with-embedded-server' '--with-partition' '--with-innodb' '--without-ndbcluster' '--with-archive-storage-engine' '--with-blackhole-storage-engine' '--with-csv-storage-engine' '--without-example-storage-engine' '--with-federated-storage-engine' '--with-extra-charsets=complex' 'CC=ccache gcc -static-libgcc' 'CFLAGS=-g -O3' 'CXXFLAGS=-g -O3' 'CXX=ccache gcc -static-libgcc'"


Are you curious what will happen if you compile your plug-in against a server that is not built the same as the deployment server? Well, the plug-in won't be "playing nice" with your server, and it is likely that something nasty will happen, such as a crash, or worse: the plugin may unintentionally change the behavior of the server, with unwelcome results such as data corruption.

So, find the mysqlbug script, (it's normally located in the MySQL bin directory) and find that fine line...

1 comment:

Arjen said...

The mysqlbug script itself is outdated/deprecated though, it stems from the era where people submitted a bugreport to the bugs mailing list rather than bugs.mysql.com
It could still serve a purpose today when people submit a bug/problem report, except it has not been properly updated to play that role.
Thus it's moderately bad to still have it float about... heck it can still send emails to the bugs@ alias at mysql; will that go anywhere? Users might actually be trying that!