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摘要： Wait occurs when a session attempts to access a block in memory, is denied and must wait until the buffer becomes available. This event happens because a buffer is either being read into the buffer ca... 阅读全文

摘要： This latch is needed when user processes try to scan the LRU (least recently used) chain containing blocks in the buffer cache. This latch must be acquired before the block can be inserted into (when ... 阅读全文

摘要： This is an Exadata wait event that occurs when doing incremental level 1 backups via RMAN. Exadata automatically offloads RMAN backup activities to the storage cells.SolutionsOffloading the RMAN backu... 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： BackgroundA user process acquires this latch to scan the SGA for database cache buffers. Blocks in the buffer cache are placed on linked lists (cache buffer chains). Blocks are put on the hash chain a... 阅读全文

摘要： This is an Exadata wait event similar to 'db file parallel read' and normally occurs during multi-block reads of non-contiguous blocks. The most common operations associated with this wait event are i... 阅读全文

摘要： This is an Exadata wait event that occurs during the shutdown of a storage cell. This is normal activity associated with shutdown processing. SolutionsIf there are queries waiting on this event, it ma... 阅读全文

摘要： This is an Exadata wait event that occurs when fast full index scans are offloaded to the storage cells. This event is related to cell smart table scan except that the object is an index.This event do... 阅读全文