Listing Chunks with SAPDBA
Listing Chunks with SAPDBA
Use
You can use SAPDBA to view information about the chunks in an Informix database.
The display differs slightly according to whether your operating system is UNIX or NT. This is due to the underlying differences in the physical environment between the two operating systems.
If the number of chunks for a dbspace is approaching the maximum or the chunk size is approaching the maximum, an alert is raised in the Release 4 alert monitor in the Computing Center Management System (CCMS) of the R/3 System. For more information, see
Monitoring the Database with the Release 4 Alert Monitor (Informix).
Prerequisites
Procedure
You see entries similar to the following examples (taken from a UNIX system):
dbsname |
dev |
rawdevice |
size[KB] |
free[KB] |
free[%] |
maxgap[KB] |
avggap[KB] |
logdbs |
4 |
data4 |
350212 |
106 |
0.0 |
106 |
106 |
logdbs |
3 |
data3 |
350212 |
106 |
0.5 |
106 |
106 |
physdbs |
3 |
data3 |
20212 |
106 |
0.5 |
106 |
106 |
physdbs |
4 |
data4 |
20212 |
106 |
0.5 |
106 |
106 |
psapbtab |
3 |
data3 |
300000 |
132326 |
44.1 |
132138 |
26465 |
psapclu |
1 |
data1 |
150000 |
58814 |
39.2 |
58814 |
58814 |
psappool |
3 |
data3 |
100000 |
84458 |
84.5 |
63978 |
42229 |
psappool |
4 |
data4 |
200000 |
10290 |
5.1 |
10290 |
10290 |
..... |
Each line refers to a chunk. The lines are displayed in alphabetical order of the dbspace to which the chunk belongs. A mirrored dbspace or a dbspace consisting of a number of chunks appears on more than one line.
The columns above are explained in the following table:
Column |
Meaning |
dbsname |
The name of the dbspace to which the chunk belongs. If a dbsname appears on two or more lines, then the dbspace is composed of two or more chunks. For example, psappool contains two chunks, one on device 3, file data3 and one on device 4, file data4. |
dev |
Depends on your operating system: – UNIX dev refers to the physical device (that is, disk drive) on which the chunk resides. A physical device normally contains a number of chunks. Therefore, the same value of dev appears on a number of different lines in this report. A question mark appears here if your R/3 System was installed before Release 2.1G. – NT dev refers to the disk drive on which the chunk resides. According to NT conventions, this is displayed as a letter, for example, C. |
size [kb] |
The total size of the chunk, in kilobytes |
free [kb] |
The free space, in kilobytes, might not be contiguous, that is, available as a single gap within the chunk. |
free [%] |
The amount of free space expressed as a percentage of the overall size of the chunk. |
maxgap [kb] |
The size of the maximum free contiguous portion of space available in the chunk, in kilobytes. You can use such a gap to extend tables residing in the dbspace to which the chunk belongs. If a very large table needs extending, the maximum gap might be needed to extend the table. |
avggap [kb] |
The size of the average free contiguous portion of space available in the chunk, in kilobytes. You can use such a gap to extend tables residing in the dbspace to which the chunk belongs. |
Result
You have a better picture of the space situation in the chunks of your Informix database. For more information, see
Management of Informix Database Growth.
See also:
Listing Chunk Paths with SAPDBA Adding a Chunk with SAPDBA Dropping a Chunk with SAPDBA Listing Chunk Paths with SAPDBA Renaming Chunk Paths with SAPDBA