It is recommended that you read through|
this entire help document to learn more
about the Compact and Repair Wizard.
Limitations of Compacting
Defragment or Compact First?
Compact and Repair Wizard is a combined tool that automatically compacts and repairs the software database. You can improve the performance of this software if you periodically defragment your hard disk and compact your database.
Because the data on a hard disk will become fragmented over time, you should periodically run a disk-defragmentation utility (or defragmenter). If you make changes often within a database, portions of the database may also become fragmented. Therefore, you should also periodically run the Compact and Repair Wizard.
A disk defragmenter will place all files, including the database file into contiguous clusters on a hard disk, making file access faster. With the exception of the Microsoft Windows NT operating system, 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 and Repair Wizard can also improve the performance of the database. This utility makes a copy of the database file and, if it is fragmented, rearranges how the database file is stored on disk. When completed, the compacted database has reclaimed wasted space, and is usually smaller than the original. By compacting the database frequently, optimal performance of the database application is ensured, and page corruptions due to hardware problems, power failures/surges, and so on are resolved.
Compacting re-stores table records into their Primary Key order. This provides the equivalent of Non-maintained Clustered Indexes, and makes the read-ahead capabilities of the software much more efficient.
Compacting also updates the table statistics within the database that are used as in queries. These statistics can become outdated as data is added, manipulated, and deleted from the various tables. Query speed will be enhanced significantly, because they are now working with data that has been rewritten to the tables in contiguous pages. Scanning sequential pages is much faster than scanning fragmented pages. Queries are forced to recompile/optimize after each database compaction.
For the Compact operation to succeed, you must have enough storage space on your hard disk for both the original and the temporary compacted database.
You cannot compact an open database. In a multi user environment, the compact operation fails if another user has the database open.
If you compact a database after running a defragmenter, you theoretically leave open disk space immediately after the database 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 and Repair Wizard, your database 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.