Limits - PolarDB - Alibaba Cloud Documentation Center

This topic describes the limits of Apsara PolarDB for PostgreSQL(Compatible with Oracle).


Node type	Maximum number of files
polar.o.x4.medium	1048576
polar.o.x4.large	2097152
polar.o.x4.xlarge	2097152
polar.o.x8.xlarge	4194304
polar.o.x8.2xlarge	8388608
polar.o.x8.4xlarge	12582912
polar.o.x8.12xlarge	20971520

Maximum number of files: includes user table files, database system table files (approximately 1,000), and log files. An Apsara PolarDB table (non-partition table) occupies three files: data file, visibility map file, and FSM file. Each index indicates a file if indexes are used. The following error message appears when you create a table after the maximum number of files is reached:

could not create file

In this case, you need to delete some tables or upgrade the specifications of your cluster.

Table 1. Other limits
Item	Limit
Root privilege of databases	PolarDB for PostgreSQL(Compatible with Oracle) does not support the superuser privilege. Instead, it supports the polar_superuser privilege as a subset of the superuser privilege.