PostgreSQL uses sequences to generate values for serial columns and serial columns are generally what is used for "auto-incrementing" columns in PostgreSQL. Sequences have names and are, in general, independent of any particular table so you could have one sequence generating unique IDs for several different tables; the sequence name is what lastInsertId wants as its argument:
For example, PDO_PGSQL() requires you to specify the name of a sequence object for the name parameter.
The sequence object created by PostgreSQL is automatically named [table]_[column]_seq, So:
$id = $db->lastInsertId('tableName_columnName_seq');
reference:http://*.com/questions/10492566/lastinsertid-does-not-work-in-postgresql