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摘要： Shareable SQL uses bind variables rather than literal values. If an application makes use of literal (unshared) SQL then this can severely limit scalability and throughput. The cost of parsing a new S... 阅读全文

摘要： Round-trip time when running "select 1 from dual" (includes network time but not connect time) on this database. SolutionIf this is high, contact your network administrator to understand network lat... 阅读全文

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： 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 a storage cell is starting and discovering disks. SolutionsThis is a normal part of starting up the storage cell in an Exadata system. If there are queri... 阅读全文

摘要： This is an Exadata wait event that occurs when a storage cell is starting and opening a cell for use. SolutionsThis is a normal part of starting up the storage cell in an Exadata system. If there are... 阅读全文

摘要： This is an Exadata wait event similar to 'db file scattered read' and typically indicates the statement is performing a full table scan or an index fast full scan. This wait event is not seen nearly a... 阅读全文