| CPI4323 |
|---|
| Message Text: |
The query access plan has been rebuilt. |
| Cause Text: |
The access plan was rebuilt for reason code &13. The reason codes
and their meanings follow: - A file or member is not the same object as the one referred to in the
access plan. Some reasons include the object being re-created, restored, or
overridden to a new object.
- Access plan was using a reusable Open Data Path (ODP), and the optimizer
chose to use a non-reusable ODP.
- Access plan was using a non-reusable Open Data Path (ODP) and the optimizer
chose to use a reusable ODP
- The number of records in member &3 of file &1 in library &2
has changed by more than 10%.
- A new access path exists over member &6 of file &4 in library &5.
- An access path over member &9 of file &7 in library &8 that
was used for this access plan no longer exists or is no longer valid.
- The query access plan had to be rebuilt because of system programming
changes.
- The CCSID (Coded Character Set Identifier) of the current job is different
than the CCSID used in the access plan
- The value of one of the following is different in the current job: date
format, date separator, time format, or time separator.
- The sort sequence table specified has changed.
- The number of active processors or the size or paging option of the storage
pool has changed.
- The system feature DB2® UDB Symmetric Multiprocessing has either been installed
or removed.
- The value of the degree query attribute has changed either by the CHGSYSVAL or CHGQRYA CL
commands or with the query options file &15 in library &16.
- A view is either being opened by a high level language open, or is being
materialized.
- A sequence object or user-defined type or function is not the same object
as the one referred to in the access plan; or, the SQL path used to generate
the access plan is different than the current SQL path.
- Query attributes have been specified from the query options file &15
in library &16.
- The access plan was generated with a commitment control level that is
different in the current job.
- The access plan was generated with a different static cursor answer set
size.
- This is the first run of the query since a prepare or compile.
- or greater. View the second level message text of the next message issued
(CPI4351) for an explanation of these reason codes.
If the reason code is 4, 5, 6, 20, or 21 and the file specified in the
reason code explanation is a logical file, then member &12 of physical
file &10 in library &11 is the file with the specified change. |
| Recovery Text: |
Excessive rebuilds should be avoided and may indicate an application
design problem. |
This message can be sent for a variety of reasons. The specific
reason is provided in the message help.
Most of the time, this message is sent when the queried table
environment has changed, making the current access plan obsolete. An example
of the table environment changing is when an index required by the query no
longer exists on the server.
An access plan contains the instructions for how a query is to
be run and lists the indexes for running the query. If a needed index is no
longer available, the query is again optimized, and a new access plan is created,
replacing the old one.
The process of again optimizing the query and building a new access
plan at runtime is a function of DB2 UDB for iSeries™.
It allows a query to be run as efficiently as possible, using the most current
state of the database without user intervention.
The infrequent appearance of this message is not a cause for action.
For example, this message will be sent when an SQL package is run the first
time after a restore, or anytime the optimizer detects that a change has occurred
(such as a new index was created), that warrants an implicit rebuild. However,
excessive rebuilds should be avoided because extra query processing will occur.
Excessive rebuilds may indicate a possible application design problem or inefficient
database management practices.