安装过程如下：进入安装包的contrib/pg_stat_statements目录，执行编译和安装动作：
1 [root@server pg_stat_statements]# pwd 2 /soft/postgresql-9.1.2/contrib/pg_stat_statements 3 [root@server pg_stat_statements]# make && make install 4 make: `all' に対して行うべき事はありません. 5 /bin/mkdir -p '/usr/local/pgsql/lib' 6 /bin/mkdir -p '/usr/local/pgsql/share/extension' 7 /bin/sh ../../config/install-sh -c -m 755 pg_stat_statements.so '/usr/local/pgsql/lib/pg_stat_statements.so' 8 /bin/sh ../../config/install-sh -c -m 644 ./pg_stat_statements.control '/usr/local/pgsql/share/extension/' 9 /bin/sh ../../config/install-sh -c -m 644 ./pg_stat_statements--1.0.sql ./pg_stat_statements--unpackaged--1.0.sql '/usr/local/pgsql/share/extension/'
在data/postgresql.conf中，进行配置：
shared_preload_libraries = 'pg_stat_statements' pg_stat_statements.max = 1000 pg_stat_statements.track = all
shared_preload_libraries = 'pg_stat_statements'，表示要在启动时导入pg_stat_statements 动态库。
pg_stat_statements.max = 1000，表示监控的语句最多为1000句。
pg_stat_statements.track = top，表示不监控嵌套的sql语句。
pg_stat_statements.track_utility = true，表示对 INSERT/UPDATE/DELETE/SELECT 之外的sql动作也作监控。
pg_stat_statements.save = true，表示当postgresql停止时，把信息存入磁盘文件以备下次启动时再使用。
重新启动 postgresql，创建sql语句：
create extension pg_stat_statements;
查询哪些sql语句执行效率慢：
- SELECT query, calls, total_time, (total_time/calls) as average ,rows,
- 100.0 * shared_blks_hit /nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent
- FROM pg_stat_statements
- ORDER BY average DESC LIMIT 10;
统计结果一直都在，重启也不会清零，那么统计结果如何清零重新统计呢？执行下面SQL即可：
- select pg_stat_statements_reset() ;