[Question]请问大佬, polar_datadir/polar_fullpage 目录占用较大, 有方法优化下吗(我只需要 原生postgresql的功能即可, 不需要额外功能) ?

[yueludanfeng]

环境

我在 openEuler 23.09 上编译了下 polardb for postgresql
发现有个问题(在 openEuler 22.03 上也是一样的), polar_datadir 下的 polar_fullpage 占用 大几百 M, 我都还没新建业务库, polar_fullpage 就 769M 了,

1. 我看默认配置中 full_page_write 是 off, 但是 polar_fullpage 是 769M, 看似 full page write 没有启用, 为啥 polar_fullpage有大几百 M, 这个是正常的吗?
2. 假设我的 checkpoint_timeout 为 20 到 30 分钟的话, 我担心 polar_fullpage 会不会达到大几个 G 甚至上十个G 呀?

我在单机上, 只想将 polardb for postgresql 当做原生 postgresql 来使用(有原生 postgresql 的功能即可, 额外功能不需要太多)
有方法能解决 polar_fullpage 占用过大问题么?

操作演示如下

[postgres@openeuler23 polar_fullpage]$ psql 
psql (PostgreSQL 15.10 (PolarDB 15.10.3.0 build bbc102d8) on x86_64-linux-gnu)
Type "help" for help.

postgres=# show polar_datadir ;
                  polar_datadir                   
--------------------------------------------------
 file-dio:///home/postgres/tmp_polardb_pg_15_data
(1 row)

postgres=# show full_page_writes ;
 full_page_writes 
------------------
 off
(1 row)

postgres=# \q
[postgres@openeuler23 polar_fullpage]$ du -sh /home/postgres/tmp_polardb_pg_15_data/*
29M     /home/postgres/tmp_polardb_pg_15_data/base
516K    /home/postgres/tmp_polardb_pg_15_data/global
4.0K    /home/postgres/tmp_polardb_pg_15_data/pg_commit_ts
8.0K    /home/postgres/tmp_polardb_pg_15_data/pg_logindex
28K     /home/postgres/tmp_polardb_pg_15_data/pg_multixact
4.0K    /home/postgres/tmp_polardb_pg_15_data/pg_replslot
4.0K    /home/postgres/tmp_polardb_pg_15_data/pg_tblspc
4.0K    /home/postgres/tmp_polardb_pg_15_data/pg_twophase
3.1G    /home/postgres/tmp_polardb_pg_15_data/pg_wal
12K     /home/postgres/tmp_polardb_pg_15_data/pg_xact
769M    /home/postgres/tmp_polardb_pg_15_data/polar_fullpage

[polardb-bot]

Hi @yueludanfeng ~ Thanks for opening this issue! 🎉

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