UPDATE
WORK PROCESS:
Update processes are used to update the database these are 2
types of updates
1)
V1
update
2)
V2
update
Note: V3 is used but it is reserved for SAP right now
1)
V1 update: It is used to handle the updates with high priority or
handles time critical updates.
2)
V2 update: These are used to update non critical updates.
Note: SAP standard programs are defined using V1 and V2
updates. If you want to define our programs especially update we need to handle
V1 and V2. However SAP not recommended defining your own update programs.
Because modularization will be difficult.
Update
Mechanism:
à User logs into the system using dialog
process.
à User creates or modifies a record.
à If the user is modifying a record the
process communicate with enqueue process to issue a lock on that record to
update.
à Dialog processes commit the transaction
and get the transaction ID and respond back to the user.
à Dialog process updates asynchronously
in to temp table.
à Update process reads the temporary
tables and update the database synchronously.
Pausing background job:
During update, patch application we
need to stopping background process.
Use the reports
BTCTRNS1 to pause background jobs,
BTCTRNS2 to un-pause background jobs.
Need
for Update process:
SAP is transaction based and each
transaction can consist of one or more steps.
Each step is
handled by a dialog process. If there is an updating word in that step it is
recorded in the temporary tables. Up on from it all the steps update process is
initialize. If any one of the step fails the transaction is rolled back and no
entries are update in to database.
Temporary
Tables:
These tables are used to store the
data temporarily by dialog process update process read the temp tables and
inherits the locks and update the database.
1) VBHDR:
It is used to store the header information such as
Lock, username, transaction ID and
update server.
2) VBDATA: It consists of the data to be update.
3) VBMOD:
It consists of the update function modules to update the database.
4) VBERROR:
It is used to store the error messages during the update.
TYPES
OF UPDATE:
1)
Local
update
2)
Synchronous
update
3)
Asynchronous
update
1)
Local update: It is used to
update the database directly. Even though it is not recommended. NATIVE SQL
statements update the database directly. (It is not advised and recommended).
2)
Synchronous update:
Update process update the database synchronously reading from temp
tables.
3)
Asynchronous update: Dialog process updates the temp tables
asynchronously (not sure about updating the database. We may have transaction
ID but it may not be updated in database.)
Update
Monitoring:
·
Go
to SM13
·
To
monitor the updates based on the following criteria.
1)
V1
executed
2)
V2
executed
3)
V1,
V2 executed.
à The update has the following
statements:
1)
INIT
2)
RUN
3)
AUTO
4)
ERROR
1) INIT:
The update is initializing.
2) RUN: The update is updating database.
3) ERROR:
The update is thrown
into error.
4)
AUTO:
If update is
deactivated give to various problems, the update jobs are thrown into error. Up
on resolving the update issue the status error will become as auto (i.e. update
is automatically update the database without any reinitialization.)
Handling
Error Updates:
The update will
be thrown in to error.
à The following:
1) While updating the database, there is no enough space in the
database. Ora1631, Ora1632, Ora1653, Ora1654,
Ora255, Ora273.
2) Problems in the
programs:
a) An exit is
used BR customer enhanced the SAP standard program.
b) There is a
bugging the program.
c) Apply node
or patch or support package.
3) Lock problems:
Update process
inherits the locks from dialog. But in some scenarios deadlocks occurs. During
deadlock inform both the users and leave the decision to the users.
(To approve to release the lock)
4) Update is deactivated:
If the system
identifies any inconstancy. It will deactivate all the entire update mechanism.
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