Reset postgresql primary key

// Login to psql and run the following 
// What is the result? 
SELECT MAX(id) FROM your_table; 
// Then run... 
// This should be higher than the last result. 
SELECT nextval('your_table_id_seq'); 
// If it's not higher... run this to try and fix it. (run a quick pg_dump first...) 
SELECT setval('your_table_id_seq', (SELECT MAX(id) FROM your_table)+1);