problem sybase autogenerated ids

I have a table in which the PK column Id of type bigint and it is populated automatically increasing order of 1,2,3...so on i notice that some times all of a sudden the ids that are generated are having very big value . for example the ids are like 1,2,3,4,5,500000000000001,500000000000002 there is a huge jump after 5...ids 6 , 7 were not used at all

i do perform delete operations on this table but i am absolutely sure that missing ids were not used before.

why does this occur and how can i fix this?

many thanks for looking in to 开发者_开发知识库this.

my env: sybase ase 15.0.3 , linux

You get this with Sybase when the system is restarted after an improper shutdown. See full description, and what to do about it, here.