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InterviewSolution
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Why A Foreground Write In Informix Decrease Performance?state The Reason For The Same? |
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Answer» foreground writes (FG) should always be zero. A foreground write is CAUSED when a session needs to have a page from disk placed into the buffer pool, but there are no clean/free buffers available. In this case, the SQLEXEC thread will PICK a page off the least RECENTLY used side of an LRU queue, write it out, and mark the page as clean. This process is time consuming for a session and should be avoided. foreground writes (FG) should always be zero. A foreground write is caused when a session needs to have a page from disk placed into the buffer pool, but there are no clean/free buffers available. In this case, the sqlexec thread will pick a page off the least recently used side of an LRU queue, write it out, and mark the page as clean. This process is time consuming for a session and should be avoided. |
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