PostgreSQL 非 B-tree 的 index 要定期 reindex 一下

來自官方文件的說明

The potential for bloat in non-B-tree indexes has not been well researched. It is a good idea to periodically monitor the index's physical size when using any non-B-tree index type.

• https://www.postgresql.org/docs/10/static/routine-reindex.html

如果 index 不是用 B-tree 記得要注意一下這個問題

查 index size 的 SQL 語法在下面

https://wiki.postgresql.org/wiki/Index_Maintenance#Index_size.2Fusage_statistics