???????SQL Server????о????????Performance Volume Maintenance Task??????????????????????????????????????0???????

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??????SQL Server?????·????????????????????о????????Performance Volume Maintenance Task?????????Windows????????????????????????????????????????WIN32 API??????ν??SE_MANAGE_VOLUME_NAME????????SQL Server???????SetFileValidData??WIN32 API????????????????????????????????????????????SE_MANAGE_VOLUME_NAME???????????????SQL Server?????????????????????????ν??High Watermark——????NTFS???????????????????д????????????????????????
????“The SetFileValidData function allows you to avoid filling data with zeros when writing nonsequentially to a file. The function makes the data in the file valid without writing to the file. As a result?? although some performance gain may be realized?? existing data on disk from previously existing files can inadvertently become available to unintended readers.”
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????“If SetFileValidData is used on a file?? the potential performance gain is obtained by not filling the allocated clusters for the file with zeros. Therefore?? reading from the file will return whatever the allocated clusters contain?? potentially content from other users. This is not necessarily a security issue at this point?? because the caller needs to have SE_MANAGE_VOLUME_NAME privilege for SetFileValidData to succeed?? and all data on disk can be read by such users.”
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