Implications/side effects of changing cache size of sequence

Question

Hi Experts,
We are on Oracle 11.2.0.2 on Solaris 10. I have a question about sequences. They are defined as NOCACHE in my database and we are seeing a lot of "row cache lock". So I am thinking of changing the sequences to cache 20 values. Does this have any other implication -except that during db restart the cached values can be lost.
Thanks,

Answer 1

@VenkatB, when you get a value from sequence, to provide consistency, sequence execute an internal commit, works like kind of autonomous transaction.edit: this is also how, after a crash sequence still get his last value.
that is because if you dont set cache and use in a loop the sequence, that cause to log file sync event. (of course you must get many values from sequence)
>
Prove it.
Log file sync may only be incidental but may happen only from the application code when they get sequence and then do a commit within a loop. In fact, log file sync need not happen just because it's committed in loop.
When user process gets sequence value, Oracle updates SEQ$ with the value to update the value. In fact, Oracle does it for almost all of the foreground code. When Oracle has to add an extent, when Oracle has to update a new datafile header, when Oracle has to autoextend a file, etc...it always inserts/updates one of the dictionary views all the time. So it's nothing new or just with sequence.
And don't confuse yourself with a timed event with a wait.
I have tested on a 11g and 10g and I don't see any log file sync waits in tkprof or v$session_event
SQL> create sequence seq_test start with 1 nomaxvalue nocache;
Sequence created.
SQL> Declare
  2   v_cnt number;
  3  Begin
  4   For i in 1..10000
  5   Loop
  6     select seq_test.nextval into v_cnt from dual;
  7   End Loop;
  8  End;
  9  /
PL/SQL procedure successfully completed.