Why windows built-in file search so slow, so fast and Everything
Excerpt: http://blog.sina.com.cn/s/blog_9f0cf4ed0102wvkq.html
(2016-07-25 13:52:54)
Reproduced
Windows Search Why slow I do not know, it seems now windows search can retrieve all file content, and powerful.
Everything is not all one by one scan files on the hard drive us, but done by reading the NTFS USN journal file system, can only retrieve the file name.
USN log is part of the system, is the Update Service Number Journal or Change Journal abbreviation, literally translated as "update sequence number", is a modified NTFS volume in the recording information related functions. The year 2000 when Microsoft released Windows, establish NTFS 5.0, while adding some new features and improvements of the old version of the file system ,, it can set the number of files and directories to monitor changes in the partition, the recording time and under the supervision of object modification modify the content. When this feature is enabled, for each NTFS volume, when the occurrence of adding, deleting and modifying information file, NTFS uses the USN journal record.
Work USN journal, is relatively simple, it is very efficient. It is time to start with an empty file, including information on each NTFS volume. Whenever NTFS volumes have changed, the changed information will immediately be added to the file. This wherein each modified record is used to identify the specific symbol in the form of logs, i.e. USN log. Each log records, including file name, file information to make the change, log what changes (add, delete, or other operations) included happened.
USN journal is equivalent to an index of a book, of course, the content of the book which happen to add, modify or delete the time, USN journal will be recorded when these changes, and use the serial number to identify specific, but it does not record which specific modify something, so the index file is very small. And when you want to find an article, you do not have to open book page by page, you can look directly through the USN journal (that is, of indexing) to know whether the article exists.
To sum up: USN journal NTFS file system, it is a system management feature that records all changes to files and folders on the volume of. "Everything" search function is also based on the log, just filter out the file name in the index in line with the conditions of the file or folder and therefore very rapidly. With the optimized version of its current speed to open the second level, it is indeed the file name retrieval tool for Windows.
Everything is not all one by one scan files on the hard drive us, but done by reading the NTFS USN journal file system, can only retrieve the file name.
USN log is part of the system, is the Update Service Number Journal or Change Journal abbreviation, literally translated as "update sequence number", is a modified NTFS volume in the recording information related functions. The year 2000 when Microsoft released Windows, establish NTFS 5.0, while adding some new features and improvements of the old version of the file system ,, it can set the number of files and directories to monitor changes in the partition, the recording time and under the supervision of object modification modify the content. When this feature is enabled, for each NTFS volume, when the occurrence of adding, deleting and modifying information file, NTFS uses the USN journal record.
Work USN journal, is relatively simple, it is very efficient. It is time to start with an empty file, including information on each NTFS volume. Whenever NTFS volumes have changed, the changed information will immediately be added to the file. This wherein each modified record is used to identify the specific symbol in the form of logs, i.e. USN log. Each log records, including file name, file information to make the change, log what changes (add, delete, or other operations) included happened.
USN journal is equivalent to an index of a book, of course, the content of the book which happen to add, modify or delete the time, USN journal will be recorded when these changes, and use the serial number to identify specific, but it does not record which specific modify something, so the index file is very small. And when you want to find an article, you do not have to open book page by page, you can look directly through the USN journal (that is, of indexing) to know whether the article exists.
To sum up: USN journal NTFS file system, it is a system management feature that records all changes to files and folders on the volume of. "Everything" search function is also based on the log, just filter out the file name in the index in line with the conditions of the file or folder and therefore very rapidly. With the optimized version of its current speed to open the second level, it is indeed the file name retrieval tool for Windows.