pg_stat_statements 已启用，但 table 不存在

Question

我已经安装了 postgresql-9.4 和运行，并且最近在官方 documentation.

的帮助下启用了 pg_stat_statements 模块

但是我在使用时遇到以下错误：

postgres=# SELECT * FROM pg_stat_statements;
ERROR:  relation "pg_stat_statements" does not exist
LINE 1: SELECT * FROM pg_stat_statements;


postgres=# SELECT pg_stat_statements_reset();
ERROR:  function pg_stat_statements_reset() does not exist
LINE 1: SELECT pg_stat_statements_reset();

我使用 postgres 用户登录到 psql。我还检查了可用的扩展列表：

postgres=# SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements'
;
        name        | default_version | installed_version |                          comment                          
--------------------+-----------------+-------------------+-----------------------------------------------------------
 pg_stat_statements | 1.2             |                   | track execution statistics of all SQL statements executed
(1 row)

下面是扩展版本查询的结果：

postgres=# SELECT * FROM pg_available_extension_versions WHERE name = 'pg_stat_statements';
        name        | version | installed | superuser | relocatable | schema | requires |                          comment                          
--------------------+---------+-----------+-----------+-------------+--------+----------+-----------------------------------------------------------
 pg_stat_statements | 1.2     | f         | t         | t           |        |          | track execution statistics of all SQL statements executed
(1 row)

我们将不胜感激。

Answer 1

未安装扩展：

SELECT * 
FROM pg_available_extensions 
WHERE 
    name = 'pg_stat_statements' and 
    installed_version is not null;

如果 table 为空，创建扩展名：

CREATE EXTENSION pg_stat_statements;

Answer 2

我第一次使用liquibase部署环境时遇到了同样的问题。我知道我的回复可能与您的问题无关，但它是第一个 google 结果，所以我认为像我这样的其他人可以带着我同样的 Liquibase 问题来到这里。

这些是在您生成第一个 xml 文件时由 liquibase 检索的 PosGreSQL 元数据表。

在我的例子中，它只是无用的自动生成代码，所以我通过删除这些行来解决它：

 <changeSet author="martinlarizzate (generated)" id="1588181532394-7">
        <createView fullDefinition="false" viewName="pg_stat_statements"> SELECT pg_stat_statements.userid,
    pg_stat_statements.dbid,
    pg_stat_statements.queryid,
    pg_stat_statements.query,
    pg_stat_statements.calls,
    pg_stat_statements.total_time,
    pg_stat_statements.min_time,
    pg_stat_statements.max_time,
    pg_stat_statements.mean_time,
    pg_stat_statements.stddev_time,
    pg_stat_statements.rows,
    pg_stat_statements.shared_blks_hit,
    pg_stat_statements.shared_blks_read,
    pg_stat_statements.shared_blks_dirtied,
    pg_stat_statements.shared_blks_written,
    pg_stat_statements.local_blks_hit,
    pg_stat_statements.local_blks_read,
    pg_stat_statements.local_blks_dirtied,
    pg_stat_statements.local_blks_written,
    pg_stat_statements.temp_blks_read,
    pg_stat_statements.temp_blks_written,
    pg_stat_statements.blk_read_time,
    pg_stat_statements.blk_write_time
   FROM pg_stat_statements(true) pg_stat_statements(userid, dbid, queryid, query, calls, total_time, min_time, max_time, mean_time, stddev_time, rows, shared_blks_hit, shared_blks_read, shared_blks_dirtied, shared_blks_written, local_blks_hit, local_blks_read, local_blks_dirtied, local_blks_written, temp_blks_read, temp_blks_written, blk_read_time, blk_write_time);</createView>
    </changeSet>

Answer 3

我在配置 Percona 监控和管理 (PMM) 时遇到过这个问题，因为一些奇怪的原因 PMM 连接到名称为 postgres 的数据库，因此必须在中创建 pg_stat_statements 扩展此数据库：

yourdb# \c postgres
postgres# CREATE EXTENSION pg_stat_statements SCHEMA public;

pg_stat_statements 已启用，但 table 不存在

pg_stat_statements enabled, but the table does not exist

postgresql

psql

pg-stat-statements