PostgreSQL 硬性限制

https://www.postgresql.org/docs/current/limits.html

在使用 pg 的时候，需要注意一些硬性限制，例如代码中写死的，这里记录一下，方便自己查阅，有的时候直接查阅官网反而因为内容太多导致忘记这些关键内容

Item	Upper Limit	Comment
database size	unlimited
number of databases	4,294,950,911
relations per database	1,431,650,303
relation size	32 TB	with the default BLCKSZ of 8192 bytes
rows per table	limited by the number of tuples that can fit onto 4,294,967,295 pages
columns per table	1,600	further limited by tuple size fitting on a single page; see note below
columns in a result set	1,664
field size	1 GB
indexes per table	unlimited	constrained by maximum relations per database
columns per index	32	can be increased by recompiling PostgreSQL
partition keys	32	can be increased by recompiling PostgreSQL
identifier length	63 bytes	can be increased by recompiling PostgreSQL
function arguments	100	can be increased by recompiling PostgreSQL
query parameters	65,535