> pg_available_extensions视图列出了可用于安装的扩展 | 列 | 类型 | 描述 | | --- | --- | --- | | name | name | 扩展名 | | default_version | text | 默认版本 | | installed_version | text | 当前已安装的扩展版本，如果没有安装则为NULL | | comment | text | 扩展的控制文件的注释字符串 | ``` postgres=# SELECT * from pg_available_extensions; name | default_version | installed_version | comment --------------------+-----------------+-------------------+------------------------------------------------------------------------ pg_stat_statements | 1.8 | 1.8 | track planning and execution statistics of all SQL statements executed first_last_agg | 0.1.4 | 0.1.4 | first() and last() aggregate functions plpgsql | 1.0 | 1.0 | PL/pgSQL procedural language pg_freespacemap | 1.2 | 1.2 | examine the free space map (FSM) pg_visibility | 1.2 | 1.2 | examine the visibility map (VM) and page-level visibility info plpython2u | 1.0 | | PL/Python2U untrusted procedural language plperl | 1.0 | | PL/Perl procedural language demo | 1.0 | 1.0 | A key/value pair data type plperlu | 1.0 | | PL/PerlU untrusted procedural language pg_trgm | 1.5 | 1.5 | text similarity measurement and index searching based on trigrams plpythonu | 1.0 | | PL/PythonU untrusted procedural language (11 rows) ```