ICNV Table conversion During Upgrades
ICNV is a configurable process that can be can be stopped and
restarted. It allows for the conversion of large tables during system uptime.
It is recommended that you execute ICNV as early as possible. This requires
more careful planning. ICNV is only available if you are using the
downtime-minimized upgrade strategy (High resource use).
SAP upgrades invariably lead to changes in the structure of
database tables. Sometimes, this means that a complete restructure is
necessary, with the conversion of each row in the table. In previous SAP
Releases, this conversion occurred during upgrade downtime, so increasing that
downtime. Incremental table conversion with transaction ICNV now lets you
perform conversions before the upgrade, that is, during
production operation.
The benefits of incremental table conversion are:
· Reduced
downtime during upgrade
· Simpler
conversion back to SAP standard for modified tables
· Conversion of
large tables during production operation
Execution
If you have tables that might benefit from incremental
conversion, then the system asks you in phase ICNVREQ to start transaction
ICNV, leading to the following:
The system asks you:
1.
Which modified tables
you want to incrementally convert back to the standard SAP table definition
2.
Which non-modified
tables you want to incrementally convert
SAP recommends that you:
· Do not archive
tables that are being incrementally converted. Instead, archive before the
conversion.
· Do not attempt
to modify tables that are being incrementally converted. These tables are
locked until the end of the upgrade, so updates (including transaction SE11)
are not possible.
· Observe
the resource usage of the database so that you can spot bottlenecks early on.
You might have problems because:
– Extra
space is required, as each converted table has to be replicated before
conversion
– Extra
transactions are produced, leading to increased logging activity
· Make
sure that enough batch work processes are available, preferably one batch work
process for each table to be converted. If you are converting a large number of
tables, transactionICNV distributes the tables to the available batch work
processes.
· Only
start the upgrade when at least 95% of tables have been converted. This means
that you have the greatest possible advantage in reducing downtime. You can
easily observe the progress of the conversion using transaction ICNV.
Steps
SAPup will prompt you to start ICNV during the Upgrade process
Start the incremental conversion (Login with TCODE ICNV – Source
environment)
Monitor the progress
Monitor the ICNV process & the DB growth closely. ICNV
requires additional resource usage of the database, as well as a sufficient
number of background work processes. It is also recommended that you execute
ICNV as early as possible. This requires more careful planning.
The system estimates the time taken for the conversion, so
helping you to plan the start of the upgrade. Large tables are converted during
uptime but the switch to the new structure is made only during
downtime(PARCONV_UPG).
