alter table add column cost 2 seconds

when the program start, it will create table and add column, but sometimes it cost 2 seconds to add column.
my sqlite version:
3.24.0 2018-06-04 19:24:41 c7ee0833225bfd8c5ec2f9bf62b97c4e04d03bd9566366d5221ac8fb199a87ca

add columns such as :
alter table 'viewsetmetadata_task' add fail_times integer default 0;
alter table 'viewsetmetadata_task' add task_status integer default 0;
alter table 'viewsetmetadata_batch_task' add fail_times integer default 0;
alter table 'viewsetmetadata_batch_task' add task_status integer default 0;