There is a known problem with Oracle statspack report in 10g, which could cost You at least one lost statspack snapshot.

The following message is written into the alert log:

ORA-00001: unique constraint (PERFSTAT.STATS$MUTEX_SLEEP_PK) violated
ORA-06512: at “PERFSTAT.STATSPACK”, line 5264
ORA-06512: at “PERFSTAT.STATSPACK”, line 104
ORA-06512: at line 1

There is a Note 382993.1 in Metalink, which describes this bug.

The workaround is simple:

alter table perfstat.stats$mutex_sleep disable constraint STATS$MUTEX_SLEEP_PK;

create index perfstat.STATS$MUTEX_SLEEP_PK on

… and check the Metalink for the news, if the bug was fixed.