Solved

Database sweep

Posted on 2004-04-03
3
2,163 Views
Last Modified: 2013-12-09
what does database sweep actually do
0
Comment
Question by:jobarb
3 Comments
 
LVL 3

Expert Comment

by:idt
ID: 10747582
A sweep performs garbage collection on the database.

As records are deleted, or updated, the old version of the row remains in place, simply marked obsolete.  Over time your database is a mixture of current versions and backversions of rows.  Depending on the activity of your database, that is how often rows are deleted or updated, a considerable amount of the total diskspace is occupied by these back versions.

When a sweep is performed, the database pages are examined to see if the page can be marked free, that is used by new data.  This can improve performance since if no free pages are available, additional disk space needs to be allocated from the OS.

Additional performance is gained since these pages are no longer read when performing natural scans, and index traversing.

You have a choice of allowing sweep to run automatically every N transactions, or manually.

Daniel
0
 
LVL 6

Accepted Solution

by:
BAlexandrov earned 50 total points
ID: 10755109
Here one very good article about Interbase specifics
http://bdn.borland.com/article/0,1410,23216,00.html
0
 

Expert Comment

by:Earl_Kaplan
ID: 10797221
Mainframe dinosaurs will remember that the sweep process is called database reorganization (reorg) and was done regularly.
0

Featured Post

Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

Join & Write a Comment

CCModeler offers a way to enter basic information like entities, attributes and relationships and export them as yEd or erviz diagram. It also can import existing Access or SQL Server tables with relationships.
Read about achieving the basic levels of HRIS security in the workplace.
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now