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怎么使用PostgreSQL扩展函数

发表于:2025-11-08 作者:千家信息网编辑
千家信息网最后更新 2025年11月08日,这篇文章主要讲解了"怎么使用PostgreSQL扩展函数",文中的讲解内容简单清晰,易于学习与理解,下面请大家跟着小编的思路慢慢深入,一起来研究和学习"怎么使用PostgreSQL扩展函数"吧!例子.
千家信息网最后更新 2025年11月08日怎么使用PostgreSQL扩展函数

这篇文章主要讲解了"怎么使用PostgreSQL扩展函数",文中的讲解内容简单清晰,易于学习与理解,下面请大家跟着小编的思路慢慢深入,一起来研究和学习"怎么使用PostgreSQL扩展函数"吧!

例子

. ./env11.sh    git clone https://github.com/MasaoFujii/pg_cheat_funcs    cd pg_cheat_funcs/    USE_PGXS=1 make    USE_PGXS=1 make install
postgres=# create extension pg_cheat_funcs ;  CREATE EXTENSION

1、打印内存上下文

postgres=# select * from pg_stat_get_memory_context();             name           |       parent       | level | total_bytes | total_nblocks | free_bytes | free_chunks | used_bytes   --------------------------+--------------------+-------+-------------+---------------+------------+-------------+------------   TopMemoryContext         |                    |     0 |      312552 |            11 |      40520 |          21 |     272032   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |       1456 |           0 |       6736   TopTransactionContext    | TopMemoryContext   |     1 |        8192 |             1 |       7744 |           1 |        448   PL/pgSQL function        | TopMemoryContext   |     1 |       16384 |             2 |       7176 |           1 |       9208   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |        560 |           0 |       7632   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |        560 |           0 |       7632   dynahash                 | TopMemoryContext   |     1 |       24528 |             2 |       2624 |           0 |      21904   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |       2096 |           0 |       6096   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |       1584 |           0 |       6608   dynahash                 | TopMemoryContext   |     1 |       24576 |             2 |      10760 |           3 |      13816   RowDescriptionContext    | TopMemoryContext   |     1 |        8192 |             1 |       6896 |           0 |       1296   MessageContext           | TopMemoryContext   |     1 |       32768 |             3 |      10904 |           1 |      21864   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |        560 |           0 |       7632   dynahash                 | TopMemoryContext   |     1 |       32768 |             3 |      16832 |           8 |      15936   TransactionAbortContext  | TopMemoryContext   |     1 |       32768 |             1 |      32512 |           0 |        256   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |        560 |           0 |       7632   TopPortalContext         | TopMemoryContext   |     1 |        8192 |             1 |       7664 |           0 |        528   PortalContext            | TopPortalContext   |     2 |        1024 |             1 |        592 |           0 |        432   ExecutorState            | PortalContext      |     3 |       49208 |             4 |      15576 |           3 |      33632   printtup                 | ExecutorState      |     4 |        8192 |             1 |       7936 |           0 |        256   Table function arguments | ExecutorState      |     4 |        8192 |             1 |       7936 |           0 |        256   ExprContext              | ExecutorState      |     4 |        8192 |             1 |       4536 |           0 |       3656   dynahash                 | TopMemoryContext   |     1 |       16384 |             2 |       3512 |           2 |      12872   CacheMemoryContext       | TopMemoryContext   |     1 |      524288 |             7 |      20960 |          26 |     503328   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           1 |       1424   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           1 |       1424   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           1 |       1424   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           1 |       1424   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           1 |       1368   EventTriggerCache        | CacheMemoryContext |     2 |        8192 |             1 |       7936 |           2 |        256   dynahash                 | EventTriggerCache  |     3 |        8192 |             1 |       2624 |           0 |       5568   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   relation rules           | CacheMemoryContext |     2 |       16384 |             5 |       7352 |           0 |       9032   index info               | CacheMemoryContext |     2 |        2048 |             2 |        648 |           2 |       1400   index info               | CacheMemoryContext |     2 |        2048 |             2 |        704 |           3 |       1344   index info               | CacheMemoryContext |     2 |        1024 |             1 |         16 |           0 |       1008   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        592 |           3 |       1456   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        3072 |             2 |       1136 |           2 |       1936   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        704 |           3 |       1344   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        1024 |             1 |         16 |           0 |       1008   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        3072 |             2 |       1136 |           2 |       1936   index info               | CacheMemoryContext |     2 |        3072 |             2 |       1136 |           2 |       1936   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        704 |           3 |       1344   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        728 |           1 |       1320   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           2 |       1424   index info               | CacheMemoryContext |     2 |        2048 |             2 |        672 |           3 |       1376   index info               | CacheMemoryContext |     2 |        2048 |             2 |        704 |           3 |       1344   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        624 |           2 |       1424   index info               | CacheMemoryContext |     2 |        1024 |             1 |         16 |           0 |       1008   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        3072 |             2 |       1136 |           2 |       1936   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        728 |           1 |       1320   index info               | CacheMemoryContext |     2 |        2048 |             2 |        728 |           1 |       1320   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        680 |           2 |       1368   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        728 |           1 |       1320   index info               | CacheMemoryContext |     2 |        1024 |             1 |         48 |           0 |        976   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        704 |           3 |       1344   index info               | CacheMemoryContext |     2 |        1024 |             1 |         16 |           0 |       1008   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        760 |           2 |       1288   index info               | CacheMemoryContext |     2 |        1024 |             1 |         16 |           0 |       1008   index info               | CacheMemoryContext |     2 |        2048 |             2 |        728 |           1 |       1320   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   index info               | CacheMemoryContext |     2 |        2048 |             2 |        952 |           1 |       1096   WAL record construction  | TopMemoryContext   |     1 |       49768 |             2 |       6368 |           0 |      43400   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |       2624 |           0 |       5568   MdSmgr                   | TopMemoryContext   |     1 |        8192 |             1 |       7432 |           0 |        760   dynahash                 | TopMemoryContext   |     1 |        8192 |             1 |        560 |           0 |       7632   dynahash                 | TopMemoryContext   |     1 |      104120 |             2 |       2624 |           0 |     101496   ErrorContext             | TopMemoryContext   |     1 |        8192 |             1 |       7936 |           0 |        256  (121 rows)

2、文本压缩

  postgres=# select pglz_compress(repeat(md5(random()::text),1024));                                                                                                                                                      pglz_compress                                                                                                        -------------------------------------------------------------------------------------------------------------------------------------   \x00800040006135663437636166003162353066626137006637356161363639003532316233336139ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f  20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f2  0ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f  20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ffff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20ff0f20e7  (1 row)

3、解压缩

pglz_decompress(bytea)    postgres=# select pglz_compress(repeat(md5(random()::text),8));                                         pglz_compress                                          --------------------------------------------------------------------------------------------   \x00010040003236666162656631003262323262636230006462656638616330003536343161383937010f20ce  (1 row)    postgres=# select pglz_decompress('\x00010040003236666162656631003262323262636230006462656638616330003536343161383937010f20ce');               pglz_decompress      ------------------------------------------------------------------------------   26fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22bcb0dbef8ac05641a89726fabef12b22  bcb0dbef8ac05641a897  (1 row)

4、查看绑定变量QUERY的PLAN COSE。

postgres=# prepare a (name) as select * from pg_class where relname=$1;PREPAREpostgres=# select * from pg_cached_plan_source('a'); generic_cost | total_custom_cost | num_custom_plans | force_generic | force_custom --------------+-------------------+------------------+---------------+--------------           -1 |                 0 |                0 | f             | f(1 row)postgres=# execute a('abc'); relname | relnamespace | reltype | reloftype | relowner | relam | relfilenode | reltablespace | relpages | reltuples | relallvisible | reltoastrelid | relhasindex | relisshared | relpersistence | relkind | relnatts | relchecks | relhasoids | relhasrules | relhastriggers | relhassubclass | relrowsecurity | relforcerowsecurity | relispopulated | relreplident | relispartition | relrewrite | relfrozenxid | relminmxid | relacl | reloptions | relpartbound ---------+--------------+---------+-----------+----------+-------+-------------+---------------+----------+-----------+---------------+---------------+-------------+-------------+----------------+---------+----------+-----------+------------+-------------+----------------+----------------+----------------+---------------------+----------------+--------------+----------------+------------+--------------+------------+--------+------------+--------------(0 rows)postgres=# select * from pg_cached_plan_source('a'); generic_cost | total_custom_cost | num_custom_plans | force_generic | force_custom --------------+-------------------+------------------+---------------+--------------           -1 |  4.61208554676785 |                1 | f             | f(1 row)postgres=# execute a('abc'); relname | relnamespace | reltype | reloftype | relowner | relam | relfilenode | reltablespace | relpages | reltuples | relallvisible | reltoastrelid | relhasindex | relisshared | relpersistence | relkind | relnatts | relchecks | relhasoids | relhasrules | relhastriggers | relhassubclass | relrowsecurity | relforcerowsecurity | relispopulated | relreplident | relispartition | relrewrite | relfrozenxid | relminmxid | relacl | reloptions | relpartbound ---------+--------------+---------+-----------+----------+-------+-------------+---------------+----------+-----------+---------------+---------------+-------------+-------------+----------------+---------+----------+-----------+------------+-------------+----------------+----------------+----------------+---------------------+----------------+--------------+----------------+------------+--------------+------------+--------+------------+--------------(0 rows)postgres=# select * from pg_cached_plan_source('a'); generic_cost | total_custom_cost | num_custom_plans | force_generic | force_custom --------------+-------------------+------------------+---------------+--------------           -1 |  9.22417109353571 |                2 | f             | f(1 row)

感谢各位的阅读,以上就是"怎么使用PostgreSQL扩展函数"的内容了,经过本文的学习后,相信大家对怎么使用PostgreSQL扩展函数这一问题有了更深刻的体会,具体使用情况还需要大家实践验证。这里是,小编将为大家推送更多相关知识点的文章,欢迎关注!

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