ARTIClE
Deep Data Objects, Memory Consumption
The example illustrates the management costs of deep components with low
data content.
ABAP_SOURCE_CODE
ABAP_EXEC
ABAP_DESCRIPTION
At the breakpoints, you can use the ABAP Debugger to display the memory
requirements of the four internal tables itab , rtab ,
ttab , and otab .
At the first breakpoint, the four tables have the same dynamic yet not
duplicative data content, that is, 1000 different integers. Whereas for
itab , the data content size of about 4 MB is only
increased by the management costs for itab itself amounting to
around 100 bytes, all other tables create management costs for each
single table row. For the deep row types in rtab , ttab ,
and otab , the data content size of 4 MB is confronted with
management costs in the order of 100, 200 and 300 MB . The costs
for the inner internal table in ttab are higher than that for the
data reference in rtab . The management costs for otab are
made up of the costs for the object references and for the internal
tables in the object references.
At the second breakpoint, all rows of each of the four tables were
initialized using FREE . Of course, this does not effect the
memory requirements of itab . In rtab , all data as well as
all management information of the individual reference variables was
deleted, leaving memory requirements of about 8 MB for the
initial references plus the management costs for rtab itself. In
ttab , all data was deleted but the individual table headers
were retained. Although the management costs could be reduced
slightly this way, this still leaves about 100 MB of pure
management costs. For otab , by contrast, the situation was
similar to rtab , leaving only the costs for the initial
references.
This example shows on the one hand that for internal tables with deep
row types the management costs may easily exceed the data content and on
the other hand that after deleting data a table with object references
is less expensive than a table with inner tables.
Documentation extract taken from SAP system, � Copyright SAP AG. All rights reserved