ACC: Defragment and Compact Database to Improve Performance
ID: Q92681
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The information in this article applies to:
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Microsoft Access versions 1.0, 1.1, 2.0, 7.0, 97
SUMMARY
Novice: Requires knowledge of the user interface on single-user computers.
You can improve the performance of Microsoft Access if you periodically
defragment your hard disk and compact your database.
MORE INFORMATION
Because the data on your hard disk becomes fragmented over time, you
should run a disk-defragmentation utility (or defragmenter)
periodically. If you often make changes to a database, portions of the
database may also become fragmented. Therefore, you should run the Compact
Database command in Microsoft Access periodically.
A disk defragmenter will place the database file in contiguous clusters on
your hard disk, making file access faster. If you do not defragment your
hard disk, the operating system may have to go to several physical
locations on the disk to retrieve the database file, making file access
slower.
Running the Compact Database command may also improve the performance of
Microsoft Access. Compact Database makes a copy of the database file and,
if it is fragmented, rearranges how the database file is stored on disk.
The compacted database file is usually smaller than the original.
Compacting can also speed up queries because it writes all the data in a
table into contiguous pages on the hard disk. Scanning sequential pages is
much faster than scanning fragmented pages.
You can use the original name for the compacted database file, or you can
use a different name to create a separate file. If you use the same name
and the database is compacted successfully, Microsoft Access automatically
replaces the original file with the compacted version.
Limitations of Compacting
- For the compact operation to succeed, you must have enough storage
space on your hard disk for both the original and the compacted
database.
- You cannot compact an open database. In a multiuser environment, the
compact operation fails if another user has the database open.
NOTE: In Microsoft Access 97, you can compact a database while it is
open, as long as the database has been opened exclusively.
Defragment or Compact First?
If you compact a database after running a defragmenter, you theoretically
leave open disk space immediately after the .MDB file on the disk,
allowing the operating system to place any additional information in the
succeeding physical clusters. This would be very fast. However, if you
defragment after running Compact Database, your .MDB may be placed on the
first part of the disk followed by the rest of your files, with no open
disk space until the end (the inside tracks) of the disk. This makes disk
access somewhat slower.
REFERENCES
For more information about compacting databases, type "compacting
databases" in the Office Assistant, click Search, and then click to view
"Compact a database to defragment the file and free disk space."
Keywords : kbusage GnlCmp
Version : 1.0 1.1 2.0 7.0 97
Platform : WINDOWS
Issue type : kbinfo
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