摘要： The session is looking for a consistent read version of data but cannot find it in the local cache. The local instance has made a request to other RAC instances for the data and is waiting on its retu... 阅读全文

摘要： The session is looking for a consistent read version of data but cannot find it in the local cache. The local instance has made a request to other RAC instances for the data and is waiting on its retu... 阅读全文

摘要： When a request for rows from a table is issued, Oracle may determine through the cost-based optimizer, which index access path is best for finding rows in a table. During this index lookup process, if... 阅读全文

摘要： The process has issued multiple I/O requests in parallel to read blocks from data files into memory and is waiting for all requests to complete. This occurs during regular activity when a session batc... 阅读全文

摘要： This event occurs in the DBWR. It indicates that the DBWR is performing a parallel write to files and blocks. When the last I/O has gone to disk, the wait ends. This wait only occurs in the DBWR proce... 阅读全文

摘要： Waits on this event indicate the statement is performing a full table scan or an index range scan. This is often reduced by adding an index or making the index more efficient.SolutionsTune the SQL sta... 阅读全文

摘要： Waits on 'db file sequential read' normally occur during index lookups when the block is not in memory and must be read from disk. They are generally considered a 'good' read unless the index being us... 阅读全文

摘要： Sometimes related to sorting operations, check to see if occurring primarily in temp tablespaces. During Direct Path operations the data is asynchronously read from the database files. At some point t... 阅读全文

摘要： Often related to sorting operations, check to see if occurring primarily in temp tablespaces.Solutions1) Reading from temp tablespacesIf the database parameter workarea_size_policy = AUTO:Increase the... 阅读全文

摘要： Direct path writes allow a session to queue an I/O write request and continue processing while the OS handles the I/O. If the session needs to know if an outstanding write is complete then it waits on... 阅读全文