11g自动分区超过最大限制

公司业务系统一张表按时间每天分区

写入数据时报错：ORA-14300: 分区关键字映射到超出允许的最大分区数的分区

ORA-14300: partitioning key maps to a partition outside maximum permitted number of partitions 
Cause: The row inserted had a partitioning key that maps to a partition number greater than 1048575
Action: Ensure that the partitioning key falls within 1048575 partitions or subpartitions.

查了一下表的分区数才2000多个，并未超出最大限制数

insert的分区字段时间为3013-01-13

分区最大数时间是从哪天开始计算的呢？