Database Defragmentation
The database defragmentation capability introduced in PSQL v12 has the following new features and enhancements in SP1:
•
Cancel All
•
Automatic Defragmentation
•
Disk Space Management
•
Defragmenting Multiple Files from the Command Line
•
Defragmentation with Open File Handles
Cancel All
From both the Defragmenter window and the
dbdefrag
command line, you can now use Cancel All to stop all analysis and defragmentation activity.
Automatic Defragmentation
Automatic defragmentation is a new feature that provides unattended defragmentation of recently opened files. Automatic defragmentation waits one hour after the last defragmentation and then checks for any file that matches the following criteria:
•
Not already defragmented in the past 24 hours
•
10 MB or larger
•
Fragmented 15% or more
•
Containing 15% or more unused space
•
Containing 5% or more records out of order
For details, see
Automatic Defragmentation
. For information about data defragmentation in general, see
Monitoring Data File Fragmentation
.
Disk Space Management
During defragmentation, the engine monitors available disk space. If your application’s need for disk space rises substantially while files are being defragmented and competition for space poses a risk to your application execution, the engine automatically cancels defragmentation requests to release resources.
Defragmenting Multiple Files from the Command Line
The dbdefrag command line utility now accepts multiple file names.
Defragmentation with Open File Handles
In PSQL v12, if a file were opened while it was undergoing defragmentation, additional defragmentation requests would be denied until that open file handle closed. In 12.10, additional defragmenting is no longer blocked.