本篇内容主要讲解“怎么使用PostgreSQL的pg_stat_statements”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“怎么使用PostgreSQL的pg_stat_statements”吧!
pg_stat_statements提供了一种跟踪所有SQL语句的手段。
进入pg_stat_statements目录,执行make/make install
[pg12@localhost pg_stat_statements]$ ls expected pg_stat_statements--1.4--1.5.sql pg_stat_statements.control Makefile pg_stat_statements--1.4.sql pg_stat_statements.o pg_stat_statements--1.0--1.1.sql pg_stat_statements--1.5--1.6.sql pg_stat_statements.so pg_stat_statements--1.1--1.2.sql pg_stat_statements--1.6--1.7.sql pg_stat_statements--unpackaged--1.0.sql pg_stat_statements--1.2--1.3.sql pg_stat_statements.c sql pg_stat_statements--1.3--1.4.sql pg_stat_statements.conf [pg12@localhost pg_stat_statements]$ make make -C ../../src/backend generated-headers make[1]: Entering directory `/data/source/postgresql-12beta1/src/backend' make -C catalog distprep generated-header-symlinks make[2]: Entering directory `/data/source/postgresql-12beta1/src/backend/catalog' make[2]: Nothing to be done for `distprep'. make[2]: Nothing to be done for `generated-header-symlinks'. make[2]: Leaving directory `/data/source/postgresql-12beta1/src/backend/catalog' make -C utils distprep generated-header-symlinks make[2]: Entering directory `/data/source/postgresql-12beta1/src/backend/utils' make[2]: Nothing to be done for `distprep'. make[2]: Nothing to be done for `generated-header-symlinks'. make[2]: Leaving directory `/data/source/postgresql-12beta1/src/backend/utils' make[1]: Leaving directory `/data/source/postgresql-12beta1/src/backend' [pg12@localhost pg_stat_statements]$ make install make -C ../../src/backend generated-headers make[1]: Entering directory `/data/source/postgresql-12beta1/src/backend' make -C catalog distprep generated-header-symlinks make[2]: Entering directory `/data/source/postgresql-12beta1/src/backend/catalog' make[2]: Nothing to be done for `distprep'. make[2]: Nothing to be done for `generated-header-symlinks'. make[2]: Leaving directory `/data/source/postgresql-12beta1/src/backend/catalog' make -C utils distprep generated-header-symlinks make[2]: Entering directory `/data/source/postgresql-12beta1/src/backend/utils' make[2]: Nothing to be done for `distprep'. make[2]: Nothing to be done for `generated-header-symlinks'. make[2]: Leaving directory `/data/source/postgresql-12beta1/src/backend/utils' make[1]: Leaving directory `/data/source/postgresql-12beta1/src/backend' /usr/bin/mkdir -p '/appdb/xdb/pg12beta1/lib/postgresql' /usr/bin/mkdir -p '/appdb/xdb/pg12beta1/share/postgresql/extension' /usr/bin/mkdir -p '/appdb/xdb/pg12beta1/share/postgresql/extension' /usr/bin/install -c -m 755 pg_stat_statements.so '/appdb/xdb/pg12beta1/lib/postgresql/pg_stat_statements.so' /usr/bin/install -c -m 644 ./pg_stat_statements.control '/appdb/xdb/pg12beta1/share/postgresql/extension/' /usr/bin/install -c -m 644 ./pg_stat_statements--1.4.sql ./pg_stat_statements--1.6--1.7.sql ./pg_stat_statements--1.5--1.6.sql ./pg_stat_statements--1.4--1.5.sql ./pg_stat_statements--1.3--1.4.sql ./pg_stat_statements--1.2--1.3.sql ./pg_stat_statements--1.1--1.2.sql ./pg_stat_statements--1.0--1.1.sql ./pg_stat_statements--unpackaged--1.0.sql '/appdb/xdb/pg12beta1/share/postgresql/extension/' [pg12@localhost pg_stat_statements]$
使用前需在配置文件中添加预加载共享链接库,否则会报错:
testdb=# create extension pg_stat_statements; CREATE EXTENSION testdb=# select * from pg_stat_statements; psql: ERROR: pg_stat_statements must be loaded via shared_preload_libraries
在postgresql.conf文件中修改shared_preload_libraries参数:
[pg12@localhost pg12db1]$ grep 'shared_preload' postgresql.conf shared_preload_libraries = 'pg_stat_statements' # (change requires restart)
注意:修改该参数后需要重启数据库实例.
下面是简单的使用:
testdb=# \x Expanded display is on. testdb=# select * from pg_stat_statements; -[ RECORD 1 ]-------+--------------------------------- userid | 10 dbid | 16384 queryid | 6343734953611294604 query | select * from pg_stat_statements calls | 2 total_time | 0.618297 min_time | 0.303231 max_time | 0.315066 mean_time | 0.3091485 stddev_time | 0.00591750000000002 rows | 2 shared_blks_hit | 0 shared_blks_read | 0 shared_blks_dirtied | 0 shared_blks_written | 0 local_blks_hit | 0 local_blks_read | 0 local_blks_dirtied | 0 local_blks_written | 0 temp_blks_read | 0 temp_blks_written | 0 blk_read_time | 0 blk_write_time | 0 -[ RECORD 2 ]-------+--------------------------------- userid | 10 dbid | 16384 queryid | -2568307067200732111 query | select * from t1 calls | 1 total_time | 876.219199 min_time | 876.219199 max_time | 876.219199 mean_time | 876.219199 stddev_time | 0 rows | 1100000 shared_blks_hit | 0 shared_blks_read | 5946 shared_blks_dirtied | 0 shared_blks_written | 0 local_blks_hit | 0 local_blks_read | 0 local_blks_dirtied | 0 local_blks_written | 0 temp_blks_read | 0 temp_blks_written | 0 blk_read_time | 0 blk_write_time | 0
查询汇总统计信息
testdb=# SELECT query, (total_time / 1000 / 60) as total, (total_time/calls) as avg FROM pg_stat_statements ORDER BY 1 DESC LIMIT 100; query | total | avg -------------------------------------+------------------------+--------------------- SELECT +| 1.5928199999999998e-05 | 0.318564 (total_time / $1 / $2) as total, +| | (total_time/calls) as avg, +| | query +| | FROM pg_stat_statements +| | ORDER BY 1 DESC +| | LIMIT $3 | | SELECT +| 4.9146500000000005e-06 | 0.294879 (total_time / $1 / $2) as total, +| | (total_time/calls) as avg +| | FROM pg_stat_statements +| | ORDER BY 1 DESC +| | LIMIT $3 | | select * from t1 | 0.014603653316666666 | 876.219199 select * from pg_stat_statements | 1.5696116666666667e-05 | 0.31392233333333336 (4 rows) ... testdb=# testdb=# SELECT testdb-# query, testdb-# round((total_time / 1000 / 60)::numeric,4) as total, testdb-# round((total_time/calls)::numeric,4) as avg testdb-# FROM pg_stat_statements testdb-# WHERE query like '%t1%' testdb-# ORDER BY 1 DESC testdb-# LIMIT 100; query | total | avg --------------------------------+--------+---------- select * from t1 where id = $1 | 0.0022 | 129.9684 select * from t1 where id < $1 | 0.0020 | 121.3334 select * from t1 | 0.0146 | 876.2192 (3 rows)
查询条件中id = xx,实际值被替换为占位符($x).
到此，相信大家对“怎么使用PostgreSQL的pg_stat_statements”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！