HP 3000 Manuals HP 3000 Manuals
Moving from MPE/iX to MPE V
If you need to move a TurboIMAGE database from MPE/iX to MPE V, you need
to perform the following tasks:
1. Disable ILR, roll-back recovery, and, if applicable, third-party
indexing. Set the critical item update (CIUPDATE) option to
DISALLOWED.
2. Check the buffer specifications to ensure that they are compatible
with MPE V. TurboIMAGE/XL buffer specifications are set at a large
fixed number. Refer to the following discussion of the BUFFSPECS
parameter of the DBUTIL >>SET command for setting the buffer
specifications for a database to be moved to MPE V.
3. If the TurboIMAGE/XL database you stored has taken advantage of
dynamic roll-back recovery, check for the presence of a dbname00
file. If the dbname00 file exists, the database needs to be
recovered. Open the database and close it again. The recovery
occurs automatically with the call to DBOPEN.
4. Store the database with DBSTORE and be sure to specify the
TRANSPORT option (see "Major Differences" below).
5. If necessary, reenable both ILR and roll-back recovery on MPE V
after the database is restored.
Major Differences
* A TRANSPORT option has been added to the DBSTORE command. When
you are transporting databases from MPE/iX to MPE V, you must use
this TRANSPORT option. To do this, supply an INFO parameter as
follows:
RUN DBSTORE;INFO="TRANSPORT"
* Disable ILR before transporting TurboIMAGE/XL databases to MPE V.
NOTE Your TurboIMAGE database may be too large to move to the MPE V
system, because with the expanded file size available on MPE/iX (4
gigabytes), data sets can exceed the MPE V file size limit (0.5
gigabytes). If you store a database on MPE/iX using DBSTORE with
the TRANSPORT option, you will receive an MPE/iX error when a data
set larger than the MPE V limit is encountered.
Buffer Specifications
For databases that will be moved to MPE V, the DBUTIL >>SET command can
be used to specify the number of input/output buffers to be allocated by
TurboIMAGE/V in the Database Buffer Area Control Block (DBB) depending on
the number of users concurrently accessing the database. The syntax of
this command follows:
>>SET database name [/maint word]
{BUFFSPECS=num buffers (from-users/ to-users)}
{ [,num buffers(from-users/to-users)]... }
For a complete syntax listing of the DBUTIL >>SET command, refer to
Chapter 8.
Parameters
BUFFSPECS is for MPE V compatibility only, because the
TurboIMAGE/XL buffer specifications are fixed at a
large default value. For databases that will be
moved to MPE V, it sets the number of buffers to be
allocated by TurboIMAGE/V in the Database Buffer
Area Control Block (DBB). The following parameters
are used with the BUFFSPECS parameter:
num buffers is the number of buffers for
the range of users specified
between the parentheses that
follow. The minimum number
of buffers allowed is 5 and
the maximum is 255. The
number of buffers allocated
and the actual amount of
performance increase obtained
depends on whether ILR is
enabled, how many users are
accessing the database, the
amount of main memory
available, and many other
factors.
from-users is the minimum number of
concurrent users (access
paths) for which the
preceding num buffers should
be allocated. The minimum
from-users value allowed is 1
and the maximum is 120. The
value must be less than the
immediately following
to-users value.
to-users is the maximum number of
concurrent users for which
the preceding num buffers
should be allocated. The
minimum to-users value
allowed is 1 and the maximum
is 120. The value must be
greater than the immediately
preceding from-users value.
Discussion
The following BUFFSPECS discussion is for databases that will be moved to
MPE V. The buffer specifications are fixed at 1280 on TurboIMAGE/XL.
The from-users and to-users counts can be the same. For example:
SET ORDERS/SELL BUFFSPECS=10(4/4)
is valid. The value of from-users must be less than or equal to the
value of to-users. In addition, the from-users/to-users ranges must be
specified in increasing order. The ranges may not overlap but they need
not be consecutive. If num buffers is not specified for a particular
number of users, the default number of buffers is used. These are the
default settings assigned by TurboIMAGE on MPE V:
b(1/2) b+4( 9/10) b+7(15/16)
b+1(3/4) b+5(11/12) b+8(17/18)
b+2(5/6) b+6(13/14) b+9(19/120)
b+3(7/8)
The value of b is equal to the largest number of search items in any
detail data set in the database plus 3, or it is equal to 8, whichever is
larger.
If p is the maximum number of search items (the path count), the value of
b can be represented as follows:
b = max (p+3,8)
For example, the largest path count for a detail data set in the ORDERS
database is 4. (This is the path count for the CUST data set.)
Therefore, the value of b for the ORDERS database is shown here:
b = max (4+3,8) = 8
The default buffer specifications in this case are:
8(1/2),9(3/4),10(5/6),11(7/8),12(9/10),13(11/12),14(13/14),15(15/16),16(17/18),17(19/120)
Example 1
:RUN DBUTIL.PUB.SYS Initiate DBUTIL execution.
:
>>SET ORDERS BUFFSPECS=5(1/120) Specify 5 buffers to be allocated for from 1 to
For database ORDERS 120 users (access paths).
BUFFER SPECIFICATIONS: DBUTIL confirms the specifications by listing them.
5(1/120)
>>
Example 2
:RUN DBUTIL.PUB.SYS
:
>>SHOW ORDERS BUFFSPECS Check the current buffer specifications.
BUFFER SPECIFICATIONS:
5(1/120)
>>SET ORDERS BUFFSPECS=30(1/30) Specify the new buffer specifications.
Here the buffers are increased for
Number of buffers must not decrease for the first 30 users. However, the
increased users as below: previous buffer setting remains the
same for the other users.
BUFFER SPECIFICATIONS:
30(1/30),5(31/120)
Buffer specifications remain unchanged
as below:
BUFFER SPECIFICATIONS:
5(1/120)
>>SET ORDERS BUFFSPECS=30(1/30),40(31/120) Specify larger number of buffers for increased number of users.
BUFFER SPECIFICATIONS: DBUTIL confirms the specifications by
30(1/30),40(31/120) listing them.
>>