SQL/MX 3.2.1 Management Manual (H06.26+, J06.15+)

STORAGE - Stats DISK \DMR11.$SYSTEM
SQL/MX Statistics:
Session Data bytes....... 81920 KB Max Data bytes... 131072 KB
Total Sessions........... 0 Active Sessions.. 0
- 4KB Blocks - - - - - - - - - - - - Reuse - - - - - - - - - -
Max...................... 32640 Attempts......... 499463
Number................... 20352 OK............... 499460
In Use................... 0 Failed FST....... 0
Failed ID........ 3
• Max Data bytes identifies the configured size of the SQL/MX buffer for the disk. In the
given examples, the disk has been configured for 131072 KB, or 128 MB, which is the default
value.
• Session Data bytes identifies the amount of virtual memory currently allocated to SQL/MX
buffer space for this DP2 process. The session data bytes can be configured to be less than
the Max Data bytes. DP2 can increase Session Data bytes to a higher value based
on resource and other factors. This value cannot exceed Max Data bytes.
• Total Sessions identifies the total number of sessions, including both active and ended
sessions.
• Active Sessions identifies the number of SQL/MX sessions stored in the buffer that are
currently active.
• MAX (under the heading 4KB Blocks) identifies the maximum number of 4 KB blocks located
in the SQL/MX buffer for the current value of Max Data bytes. It can also be interpreted
as the maximum number of 4 KB blocks that will be located in the SQL/MX buffer when the
Session Data bytes are equal to the Max Data bytes.
• Number (under the heading 4KB Blocks) identifies the number of 4 KB blocks located in
the SQL/MX buffer for the current value of Session Data bytes.
• In Use under 4KB Blocks identifies the number of 4 KB blocks in the buffer that are
currently in use or reusable.
• Attempts under Reuse identifies the number of times an attempt has been made to reuse
plan fragments located in the SQL/MX buffer.
• OK under Reuse identifies the number of times a successful attempt has been made to reuse
plan fragments located in the SQL/MX buffer.
• Failed FST under Reuse identifies the number of plan fragments that are not located in
the free space table of the SQL/MX buffer and not available for reuse. Failed ID under
Reuse identifies the number of plan fragments that are present in the free space tables but
whose IDs reported that they could not be reused. Together, Failed FST and Failed ID indicate
the current number of unsuccessful attempts that have been made to reuse plan fragments,
whether missing or unusable. For example, an unsuccessful attempt might result because one
or more 4 KB blocks of the query fragment space has been stolen by another query. When
this happens, the missing query plan must be reloaded.
The Failed FST and Failed ID fields provide the most important information about reuse
failures. You should monitor these values over a period of time, noting changes and trends in the
failure rates as different applications execute or when new resources are added.
For more information about methods for reducing the incidence of reuse failures in an SQL/MX
buffer, see “Strategies for Reducing Reuse Failures” (page 302).
Publish/Subscribe counters
4-> stats disk $data02,sqlmx
STORAGE - Stats DISK \DMR15.$DATA02
300 Enhancing SQL/MX Database Performance