ORA-00001 unique constraint (%s.%s) violated

Cause: An UPDATE or INSERT statement attempted to insert a duplicate key. For Trusted Oracle configured in DBMS MAC mode, you may see this message if a duplicate entry exists at a different level. Action: Either remove the unique restriction or do not insert the key.

Oracle Wait Events

When writing posts on performance tuning I felt that there needs to be a my-version of description of Oracle Wait Events along with Access method and Process & Memory Architecture. Thus this series is to start the Oracle Wait events which are common in any Database Environment BUT has a lot of story. db file…

db file scattered read – oracle wait event

DB File scattered read wait event occurs when an oracle process waits for a physical read of multiple oracle blocks from the disk. This wait identifies that a full scan (Full Table Scan or Index fast full scan) is occurring BUT during this read the blocks are read into memory locations that are not physically…

db file sequential reads – Oracle wait event

DB file sequential reads wait event comes under the User I/O wait class. In any busy system this is one of the most common wait event and normally appears in the top 5 wait events. In this post we’ll understand whats happening during this wait event. In simple words, Db file sequential reads wait event…