Shrinking file size

Over time, your data files grow, as additional information is added to them.  The daily posting of your sales tickets, and your inventory receiving, all add records to your history files.  Some of these files can become very large.  This affects the performance of your system.

At the operating system level, accessing a very large file, requires more steps and disk reads and writes, than a smaller file.  This is due to the internal disk directories that keep track of where all of the pieces of a file physically reside on the disk. They can get so large that they are broken into pieces themselves.  To add to the file, the operating system accesses the main disk directory, which sends it to another piece of the directory, which sends it to yet another, and so on.  This may occur numerous times, before it actually gets to the point of accessing the information needed.

Adding to a large file is even worse, as some of the disk directory information needs to be rewritten.

If you purge your history files, the records that are purged from them are deleted.  However, they are only marked as deleted in the file.  They are not removed from the file. The size of the file is not reduced.

After a major purge, you should physically shrink the file.  How this is done, depends on the software you are using.  Some use an export/import routine, where the data is dumped to another file, and then read back, creating a new, smaller file.  Others have a rebuild or shrink function, that does much the same thing, but in a single step (from the user’s viewpoint).

Another advantage of shrinking your files is that usually the resulting file may be less fragmented on the disk. This can increases performance.  This is not always the case. It can depend on how fragmented the disk is to start with, as well as the method that is used to shrink the file.

To optimize you disk you may want to use a defragmentation program.  These utilities try to create each file with the minimum number of pieces.  Physical disk activity and delays are then reduced when the file is used.  There are many good defragmenters available.  Your OS will normally include one.  For the Windows environment you mat want to try the Defraggler from Piriform.  It is an excellent shareware program to start with. 

To clarify the condition of your disk files and the opportunities improve their performance, contact us at CCS Retail Systems Support.  We have customers with all sizes of systems.  Some have large disks and many simultaneous users. 

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