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Monitoring Tblspaces

Use the xctl onstat -g ppf option to display the number of read and write calls for each table fragment. To display information about the fragments on a single coserver, issue this command on each coserver and specify the coserver number after the -c flag.

Although the read and write calls do not show how many disk reads and writes occurred, you can still determine if the I/O activity is balanced across fragments. Compare the number of reads or writes for each fragment to see if they are about the same or if some are proportionally greater than others.

The output sample in Figure 9 shows a small sample for two tables that are fragmented across two coservers in a test database. To see information about tablespace activity for a single table, enter the following command:

Figure 9. Sample onstat --g ppf Output
Partition profiles
partnum  name             lkrqs lkwts dlks touts isrd iswrt isrwt isdel bfrd bfwrt seqsc 
...
50002    test:ordr        77076   0     0    0     0    0     0    0    4856  6493    0 
50003    test:dist         5964   0     0    0     0    0     0    0    1162   503    0 
...
60002    test:ordr        42924   0     0    0     0    0     0    0    8265  3616    0 
60003    test:dist         5533   0     0    0     0     0    0    0    1160   509    0
...

The output displays the following information.

Column Name
Description
partnum
The tablespace number
name
The database and table name
lkrqs
The number of lock requests
dlks
The number of deadlocks
touts
The number of deadlock timeouts
isrd
The number of disk reads
iswrt
The number of disk writes
isdel
The number of deletes
bfwrt
The number of buffer writes
bfrd
The number of buffer reads
seqsc
The number of sequential scans

The xctl onstat -t option also displays information about active tblspaces on all coservers. However, it does not display the table name.

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