Listing Dbspaces with SAPDBA
Listing Dbspaces with SAPDBA
Use
You can use SAPDBA to view information about the dbspaces in an Informix database.
To avoid downtime due to dbspaces running out of space, use this report regularly to monitor your dbspaces.
If the amount of free space in a dbspace is very low or tables cannot be extended with the full next extent size required, 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).
For more information, see
Database Growth Monitoring.Prerequisites
Procedure
You see entries similar to the following examples:
dbsname |
mirrored/ |
size |
free |
free |
maxnext |
avgnext |
objs |
maxgap |
avggap | |
|
temporary |
[KB] |
[KB] |
% |
[KB] |
[KB] |
[KB] |
[KB] | ||
logdbs |
M |
350212 |
106 |
0.0 |
100 |
100 |
1 |
106 |
106 | |
physdbs |
M |
20212 |
106 |
0.5 |
100 |
200 |
1 |
106 |
106 | |
psapbtap |
300000 |
132326 |
44.1 |
10240 |
198 |
871 |
132138 |
26465 | ||
.... |
||||||||||
tmpdbs1 |
T |
102400 |
102046 |
99.7 |
100 |
58 |
2 |
958223 |
34015 | |
Summary DB: |
5.55GB |
0.78GB |
14.0% (‘free’ without temp dbspaces) | |||||||
Each line refers to a dbspace, except the final line Summary DB, which refers to the entire database. Temporary dbspaces are not shown in the Summary DB line.
The columns above are explained in the following table:
Column |
Meaning |
dbsname |
The name of the dbspace, listed in alphabetical order |
mirrored/ |
Refers to whether the dbspace is replicated on a second disk drive for extra data reliability, or whether it is a temporary dbspace. M means mirroring is switched on. T means the dbspace is temporary. It is not possible for a dbspace to be both mirrored and temporary. For more information about temporary dbspaces, refer to your Informix documentation. |
size [KB] |
The total size of the dbspace, in kilobytes, including all chunks allocated to the dbspace (even if these chunks are partly empty). |
free [KB] |
The remaining free space available in the dbspace, in kilobytes. Any space allocated to tables is excluded from this figure. In other words, this refers to the available space left in the dbspace to extend tables. |
free % |
The amount of free space expressed as a percentage of the overall size of the dbspace. If this is very small (except in the case of logdbs and physdbs ), you need to extend the dbspace. Refer to Adding a Chunk with SAPDBA. |
maxnext [KB] |
The largest next extent of any table in the dbspace, in kilobytes. If the table with the largest extent received an inflow of data and needed to be extended, this is the amount of space required for the extension. If this amount of space is not available in full, the database server simply acquires the next largest available contiguous portion of space it can find (but no error message appears). |
avgnext [KB] |
The average next extent of all tables in the dbspace, in kilobytes. The next extent for a table that needed to be extended would, on average, be this figure. |
objs |
The number of objects in the dbspace, including temporary and system tables. When you add a new dbspace, this is always set to 1 because the database server immediately sets up its own system table in the new dbspace. |
maxgap [KB] |
The size of the maximum free contiguous portion of space available in the dbspace, in kilobytes. You can use such a gap to extend tables residing in the dbspace. If a very large table needs extending, the maximum gap might be needed to extend the table. |
avggap [KB] |
The average size of available contiguous space in the dbspace, in kilobytes. You can use such a gap to extend tables residing in the dbspace. |
Result
You have a better picture of the space situation for the dbspaces of your Informix database. Be sure to add a chunk to a dbspace that is getting too full.
For more information about space management, see
Management of Informix Database Growth.
See also:
Adding a Dbspace with SAPDBA Dropping a Dbspace with SAPDBA