code pal for ABAP > Documentation > COLLECT restriction
The ABAP - Keyword Documentation says:
Rule
Do not fill standard tables with collections of lines
Only use the statement
COLLECTfor hashed tables or sorted tables with a unique key. Do not use it any more for standard tables.Details
The statement
COLLECTis based on unique entries with respect to the primary key and stable key administration. This means that not all categories of internal tables are suitable forCOLLECT:
- If the statement
COLLECTis applied to a standard table, this table first needs its own internal hash administration. Change operations on the table can invalidate this temporary hash administration. After a change operation of this type, the following COLLECT statements must resort to a linear search, which can affect performance considerably. The primary key of a standard table is also never unique.COLLECTcan be used for sorted tables and hashed tables without any problems since these, unlike standard tables, always have a separate, stable key administration that can be utilized by COLLECT.COLLECTcan work properly for sorted tables only if the primary key is unique. If a sorted table has a non-unique key, only COLLECT can be used to fill the table, which is difficult to guarantee. In hashed tables, the key values are always unique.
The check searches for COLLECT statements whose argument are internal tables typed as SORTED TABLE ... WITH NON-UNIQUE KEY or STANDARD TABLE.
Change the internal table to be a sorted or hashed table as recommended by the ABAP keyword documentation, or perform the collection manually.
In exceptional cases, you can suppress this finding by using the pseudo comment “#EC COLLECT which should be placed after the COLLECT statement:
COLLECT entry INTO table. "#EC COLLECT