Ubuntu
bitsCN.com选用较好的编译器和较好的编译器选项,这样应用可提高性能10-30%,这个对大多数程序都非常重要
Mysql的编译,不同的版本具体的配置方式是有差别的
旧版的配置形式参考
这个形式主要是使用configure,具体参考
http://www.cnblogs.com/hemhem/archive/2011/03/14/2087481.html
http://blog.csdn.net/bing19880122/article/details/5830650
http://flyingdutchman.iteye.com/blog/1901149
MySQL cMake 新老参数对比及 cMake 配置及安装方法详解 http://waynerqiu.com/7/153.html
新版Cmake形式的配置
http://www.cmake.org/
http://www.cnblogs.com/2018/p/3091616.html
mysql配置
http://dev.mysql.com/doc/refman/5.6/en/source-configuration-options.html
http://dev.mysql.com/doc/refman/5.6/en/environment-variables.html
环境变量和CMAKE配置结合可以进行配置
如下是一个实例
#CMAKE_BUILD_TYPE Debug:-g Release:-O2 RelWithDebInfo:-O2 -g MinSizeRel:-Os
#WITH_EMBEDDED_SERVER Whether to build the libmysqld embedded server library.
#WITH_PARTITION_STORAGE_ENGINE 表分区
#-DWITH_ASAN=1 / #must gcc > 4.5 参考4.8.2
#DENABLE_DOWNLOADS google MOCK test
cmake . /
-DCMAKE_INSTALL_PREFIX=/usr/local/mysql /
-DCMAKE_BUILD_TYPE=Release /
-DSYSCONFDIR=/etc /
-DINSTALL_SBINDIR=/usr/local/mysql/bin /
-DMYSQL_DATADIR=/usr/local/mysql/data /
-DMYSQL_UNIX_ADDR=/tmp/mysql.sock /
-DENABLED_LOCAL_INFILE=1 /
-DMYSQL_TCP_PORT=3306 /
-DDEFAULT_CHARSET=utf8 /
-DDEFAULT_COLLATION=utf8_general_ci /
-DWITH_EMBEDDED_SERVER=0 /
-DWITH_MYISAM_STORAGE_ENGINE=1 /
-DWITH_INNOBASE_STORAGE_ENGINE=1 /
-DWITH_PARTITION_STORAGE_ENGINE=1 /
-DWITH_ARCHIVE_STORAGE_ENGINE=0 /
-DWITH_BLACKHOLE_STORAGE_ENGINE=0 /
-DWITH_MEMORY_STORAGE_ENGINE=0 /
-DWITH_PERFSCHEMA_STORAGE_ENGINE=0 /
-DWITH_EXTRA_CHARSETS=none /
-DWITH_DEBUG=0 /
# -DWITH_ASAN=1 /
# -DENABLE_DOWNLOADS=0 /
#end of cmake
注意-DWITH_ASAN=1这个选项需要GCC的版本在4.5以上,而Ubuntu10上默认的GCC是4.4
GCC编译升级过程
http://ftp.tsukuba.wide.ad.jp/software/gcc/releases/gcc-4.8.2/gcc-4.8.2.tar.gz 从这下载GCC
使用如下的脚本可以进行升级
#!/bin/bash
# gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1)
:
ftp://gcc.gnu.org/pub/gcc/infrastructure/
GNU Multiple Precision Library (GMP) version 4.3.2 (or later)
MPFR Library version 2.4.2 (or later)
MPC Library version 0.8.1 (or later)
EOF
gccver=4.8.2
gmpver=4.3.2
mpfrver=2.4.2
mpcver=0.8.1
# where you put the downloaded source packages
pkgdir=.
# where you will build gcc
rootdir=gcc-${gccver}
# where you want to install gcc
prefix=/opt/gcc-${gccver}
# the languages you want gcc to support
langs=c,c++
#0 unpack file
:
#Create a new directory on a disk with plenty of space and unpack the sources there:
mkdir -p ${rootdir}
tar xzf ${pkgdir}/gcc-${gccver}.tar.gz
tar xjf ${pkgdir}/gmp-${gmpver}.tar.bz2
tar xjf ${pkgdir}/mpfr-${mpfrver}.tar.bz2
tar xzf ${pkgdir}/mpc-${mpcver}.tar.gz
#Next, move the prerequisite sources into the gcc source directory:
mv gmp-${gmpver} ${rootdir}/gmp
mv mpfr-${mpfrver} ${rootdir}/mpfr
mv mpc-${mpcver} ${rootdir}/mpc
EOF
#两种方式的编译和安装
#1.1 build on source dir
pushd ${rootdir}
#make clean
#默认的gcc支持32/64的双编译 gcc.gnu.org/wiki/FAQ#gnu_stubs-32.h glibc-devel-32bit 或 --disable-multilib
./configure --prefix=${prefix} --enable-languages=${langs} --disable-multilib
make
make install
popd
#1.2 build on other dir
:
#Now create a build directory and change to it
mkdir -p objdir
cd objdir
#Now configure gcc:
mkdir -p ${prefix}
../${rootdir}/configure --prefix=${prefix} --enable-languages=${langs} --disable-multilib
#configure --prefix=/opt/gcc-4.8.2 --enable-languages=c,c++
#Now build gcc:
make
#Finally, install gcc:
make install
#fixincludes 目录没有拷贝的问题,估计是--disable-multilib
cd ..
EOF
###代码+编译文件 2.6G
#2 更改当前的默认 #具体可检索"更改Ubuntu gcc、g++默认编译器版本"
#修改默认gcc和g++为4.4的版本
sudo update-alternatives --remove-all gcc
sudo update-alternatives --remove-all g++
sudo update-alternatives --install /usr/bin/gcc gcc /opt/gcc-4.8.2/bin/gcc 40
sudo update-alternatives --install /usr/bin/g++ g++ /opt/gcc-4.8.2/bin/g++ 40
#配置默认的gcc和g++
sudo update-alternatives --config gcc
sudo update-alternatives --config g++
#3 系统的C++库覆盖
rm -f /usr/lib/libstdc++*
cp -f /opt/gcc-4.8.2/lib64/libstdc++.so.6.0.18 /usr/lib/.
cp -f /opt/gcc-4.8.2/lib64/libstdc++.so.6 /usr/lib/.
注意其中的--disable-multilib这个选项需要加上,因此默认的gcc是可以在64为平台上编译出32,64两种程序,因此编译版的gcc升级时就需要32位的头文件,如果没有安装的话,这个是无法编译的。
当然也有一些简化的方式,需要联网升级,如下的这个说明
http://www.qtcn.org/bbs/apps.php?q=diary&a=detail&did=1456&uid=139371
编译安装
此时就可以加上 -DWITH_ASAN=1 / 进行编译了
注意:为了提高性能,我们只需要编译需要的功能即可
成功后的安装,就非常简单了,类似如下的脚本过程
make install
#sudo cp -f my.cnf /etc/my.cnf
#sudo chmod 0444 /etc/my.cnf
sudo sh -c 'groupadd mysql'
sudo sh -c 'useradd -r -g mysql mysql'
sudo chown -R mysql /usr/local/mysql/data
sudo /usr/local/mysql/scripts/mysql_install_db --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data
#sudo cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql
/usr/local/mysql/support-files/mysql.server start
login="/usr/local/mysql/bin/mysql -uroot -D mysql -e"
pass="/usr/local/mysql/bin/mysql -uroot -p123456 -D mysql -e"
${login} "update mysql.user set password=PASSWORD('123456') where user='root';"
${login} "flush privileges;"
详细的资料和脚本参考 http://pan.baidu.com/s/1Cc7cr
Gcc版本切换的脚本
由于新版的gcc的支持了C++11标准,默认要求差别较大,如果现有的工程需要低的版本的话,可以使用如下的形式对系统的gcc进行自动切换
#!/bin/bash
if [ $# = 1 ] ; then
#4.4 目前的Ubuntu10都是gcc 4.4
#修改默认gcc和g++
sudo update-alternatives --remove-all gcc
sudo update-alternatives --remove-all g++
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.4 40
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.4 40
#配置默认的gcc和g++
sudo update-alternatives --config gcc
sudo update-alternatives --config g++
#系统的C++库覆盖 gcc 4.4
# rm -f /usr/lib/libstdc++*
# cp -f gcc4.4/libstdc++.so.6.0.13 /usr/lib/.
# ln -s /usr/lib/libstdc++.so.6.0.13 /usr/lib/libstdc++.so.6
else
#4.8
#gcc-4.8.2.tar.gz 安装到/opt
if [ -d /opt/gcc-4.8.2 ]; then
echo "gcc 4.8.2 installed"
else
tar xzf gcc-4.8.2.tar.gz -C /opt
fi
#修改默认gcc和g++
sudo update-alternatives --remove-all gcc
sudo update-alternatives --remove-all g++
sudo update-alternatives --install /usr/bin/gcc gcc /opt/gcc-4.8.2/bin/gcc 40
sudo update-alternatives --install /usr/bin/g++ g++ /opt/gcc-4.8.2/bin/g++ 40
#配置默认的gcc和g++
sudo update-alternatives --config gcc
sudo update-alternatives --config g++
#系统的C++库覆盖
# rm -f /usr/lib/libstdc++*
# cp -f /opt/gcc-4.8.2/lib64/libstdc++.so.6.0.18 /usr/lib/.
# cp -f /opt/gcc-4.8.2/lib64/libstdc++.so.6 /usr/lib/.
fi
#libstdc++.so.6 经试验选用高的libstdc++.so.6.0.18版本可以运行,具体都我们的应用有没有问题待验证
gcc -v
参考资料
这里有如上的相关资料和内容 http://pan.baidu.com/s/1Cc7cr
http://www.cnblogs.com/2018/p/3482263.html
http://www.cnblogs.com/2018/p/3464638.html
这两篇已经介绍了clang的安装和编译c++库的过程,下面会再讲讲mysql的clang编译安装过程
bitsCN.com
MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.

The MySQL learning path includes basic knowledge, core concepts, usage examples, and optimization techniques. 1) Understand basic concepts such as tables, rows, columns, and SQL queries. 2) Learn the definition, working principles and advantages of MySQL. 3) Master basic CRUD operations and advanced usage, such as indexes and stored procedures. 4) Familiar with common error debugging and performance optimization suggestions, such as rational use of indexes and optimization queries. Through these steps, you will have a full grasp of the use and optimization of MySQL.

MySQL's real-world applications include basic database design and complex query optimization. 1) Basic usage: used to store and manage user data, such as inserting, querying, updating and deleting user information. 2) Advanced usage: Handle complex business logic, such as order and inventory management of e-commerce platforms. 3) Performance optimization: Improve performance by rationally using indexes, partition tables and query caches.

SQL commands in MySQL can be divided into categories such as DDL, DML, DQL, DCL, etc., and are used to create, modify, delete databases and tables, insert, update, delete data, and perform complex query operations. 1. Basic usage includes CREATETABLE creation table, INSERTINTO insert data, and SELECT query data. 2. Advanced usage involves JOIN for table joins, subqueries and GROUPBY for data aggregation. 3. Common errors such as syntax errors, data type mismatch and permission problems can be debugged through syntax checking, data type conversion and permission management. 4. Performance optimization suggestions include using indexes, avoiding full table scanning, optimizing JOIN operations and using transactions to ensure data consistency.

InnoDB achieves atomicity through undolog, consistency and isolation through locking mechanism and MVCC, and persistence through redolog. 1) Atomicity: Use undolog to record the original data to ensure that the transaction can be rolled back. 2) Consistency: Ensure the data consistency through row-level locking and MVCC. 3) Isolation: Supports multiple isolation levels, and REPEATABLEREAD is used by default. 4) Persistence: Use redolog to record modifications to ensure that data is saved for a long time.

MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen

MySQL is suitable for small and large enterprises. 1) Small businesses can use MySQL for basic data management, such as storing customer information. 2) Large enterprises can use MySQL to process massive data and complex business logic to optimize query performance and transaction processing.

InnoDB effectively prevents phantom reading through Next-KeyLocking mechanism. 1) Next-KeyLocking combines row lock and gap lock to lock records and their gaps to prevent new records from being inserted. 2) In practical applications, by optimizing query and adjusting isolation levels, lock competition can be reduced and concurrency performance can be improved.


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