Monitoring active tblspaces

Monitor tblspaces to determine which tables are active. Active tables are those that a thread has currently opened.

Output from the onstat -t option includes the tblspace number and the following four fields.

Field: Description
npages: Pages allocated to the tblspace
nused: Pages used from this allocated pool
nextns: Number of extents used
npdata: Number of data pages used

If a specific operation needs more pages than are available (npages minus nused), a new extent is required. If enough space is available in this chunk, the database server allocates the extent here; if not, the database server looks for space in other available chunks. If none of the chunks contains adequate contiguous space, the database server uses the largest block of contiguous space that it can find in the dbspace. onstat -t output shows an example of the output from this option.

Figure 1: onstat -t output

Tblspaces
 n address  flgs ucnt tblnum   physaddr npages nused  npdata nrows  nextns
 0 422528   1    1    100001   10000e   150    124    0      0      3
 1 422640   1    1    200001   200004   50     36     0      0      1
54 426038   1    6    100035   1008ac   3650   3631   3158   60000  3
62 4268f8   1    6    100034   1008ab   8      6      4      60     1
63 426a10   3    6    100036   1008ad   368    365    19     612    3
64 426b28   1    6    100033   1008aa   8      3      1      6      1
193 42f840  1    6    10001b   100028   8      5      2      30     1
 7 active, 200 total, 64 hash buckets