Some more technical details about SAP note
Some more technical details about SAP note
（Creative Commons）
I use this note 2184333 which I am responsible for as an example:
In order to research the technical design of SAP note, I write a simple tool for analysis.
How to use this tool
paste the following source code to create a report and run:
REPORT znote.
PARAMETERS: note TYPE cwbntkeylg-numm OBLIGATORY DEFAULT '2184333'.
DATA: lv_insta TYPE cwbntinsta,
ls_note_key TYPE cwbntkeylg,
lv_full_length TYPE i,
lt_comp TYPE abap_compdescr_tab,
lv_data_bin TYPE xstring,
lv_code_delta_bin TYPE xstring,
lt_object_data_bin TYPE cwbci_t_objdelta,
lv_rfcmsg LIKE scwbrfcmsg-text,
lv_key TYPE hash160,
lv_check_key TYPE hash160,
lv_offset TYPE i,
lv_max_length TYPE i,
lv_data TYPE xstring,
lv_chunk_data TYPE xstring,
lv_unzipped_size TYPE i,
lt_cwbnthead LIKE cwbnthead OCCURS 0,
lt_cwbntstxt LIKE cwbntstxt OCCURS 0,
lt_cwbntdata TYPE bcwbn_note_text OCCURS 0,
lt_cwbntdata_html TYPE bcwbn_notehtml_text OCCURS 0,
lt_cwbntvalid LIKE cwbntvalid OCCURS 0,
lt_cwbntci LIKE cwbntci OCCURS 0,
lt_cwbntfixed LIKE cwbntfixed OCCURS 0,
lt_cwbntgattr LIKE cwbntgattr OCCURS 0,
lt_cwbcihead LIKE cwbcihead OCCURS 0,
lt_cwbcidata TYPE bcwbn_cinst_delta OCCURS 0,
lt_cwbcidata_ref TYPE cwb_deltas,
lt_cwbcivalid LIKE cwbcivalid OCCURS 0,
lt_cwbciinvld LIKE cwbciinvld OCCURS 0,
lt_cwbcifixed LIKE cwbcifixed OCCURS 0,
lt_cwbcidpndc LIKE cwbcidpndc OCCURS 0,
lt_cwbciobj LIKE cwbciobj OCCURS 0,
lt_cwbcmpnt LIKE cwbcmpnt OCCURS 0,
lt_cwbcmtext LIKE cwbcmtext OCCURS 0,
lt_cwbcmlast LIKE cwbcmlast OCCURS 0,
lt_cwbdehead LIKE cwbdehead OCCURS 0,
lt_cwbdeprdc LIKE cwbdeprdc OCCURS 0,
lt_cwbdetrack LIKE cwbdetrack OCCURS 0,
lt_cwbdeequiv LIKE cwbdeequiv OCCURS 0,
lt_cwbcinstattr TYPE cwbci_t_attr.
START-OF-SELECTION.
PERFORM main.
FORM main.
ls_note_key-langu = 'E'.
ls_note_key-numm = note.
CALL FUNCTION 'SLIC_GET_LICENCE_NUMBER'
IMPORTING
license_number = lv_insta.
CALL FUNCTION 'BHREM_SAPNOTE_RFC_GET_CHUNKED' DESTINATION 'SAPSNOTE'
EXPORTING
is_note_key_lg = ls_note_key
iv_check_status = 'X'
iv_insta_cust = lv_insta
iv_na_fmt_id = 3
IMPORTING
ev_full_length = lv_full_length
ev_chunk_data = lv_chunk_data
CHANGING
cv_key = lv_key
cv_chunk_offset = lv_offset
cv_chunk_max_length = lv_max_length
EXCEPTIONS
system_failure = 1 MESSAGE lv_rfcmsg
communication_failure = 2 MESSAGE lv_rfcmsg
note_not_exist = 3
note_not_released = 4
note_langu_not_exist = 5
pack_error = 6
note_incomplete = 7
note_format_error = 8
protocol_error = 9
OTHERS = 10.
IF sy-subrc <> 0.
WRITE: / 'note download failed: ', lv_rfcmsg.
RETURN.
ENDIF.
WRITE: / 'size ( compressed ):', lv_full_length.
lv_data = lv_chunk_data.
CALL FUNCTION 'CALCULATE_HASH_FOR_RAW'
EXPORTING
alg = 'SHA1'
data = lv_data
IMPORTING
hash = lv_check_key
EXCEPTIONS
unknown_alg = 1
param_error = 2
internal_error = 3
OTHERS = 4.
IF lv_check_key <> lv_key.
WRITE:/ 'note key verification failed.'.
RETURN.
ENDIF.
cl_abap_gzip=>decompress_binary( EXPORTING gzip_in = lv_data
IMPORTING raw_out = lv_data ).
CALL TRANSFORMATION id SOURCE XML lv_data
RESULT xml_data_bin = lv_data_bin
xml_code_delta_bint = lv_code_delta_bin
xml_object_data_bin = lt_object_data_bin.
CALL FUNCTION 'SCWN_NOTE_UNPACK_XML'
EXPORTING
iv_data_bin = lv_data_bin
iv_code_delta_bin = lv_code_delta_bin
it_object_data_bin = lt_object_data_bin
IMPORTING
et_cwbnthead = lt_cwbnthead
et_cwbntstxt = lt_cwbntstxt
et_htmltext = lt_cwbntdata_html
et_cwbntdata = lt_cwbntdata
et_cwbntvalid = lt_cwbntvalid
et_cwbntci = lt_cwbntci
et_cwbntfixed = lt_cwbntfixed
et_cwbntgattr = lt_cwbntgattr
et_cwbcihead = lt_cwbcihead
et_cwbcidata = lt_cwbcidata
et_cwbcidata_ref = lt_cwbcidata_ref
et_cwbcivalid = lt_cwbcivalid
et_cwbciinvld = lt_cwbciinvld
et_cwbcifixed = lt_cwbcifixed
et_cwbcidpndc = lt_cwbcidpndc
et_cwbciobj = lt_cwbciobj
et_cwbcmpnt = lt_cwbcmpnt
et_cwbcmtext = lt_cwbcmtext
et_cwbcmlast = lt_cwbcmlast
et_cwbdehead = lt_cwbdehead
et_cwbdeprdc = lt_cwbdeprdc
et_cwbdetrack = lt_cwbdetrack
et_cwbdeequiv = lt_cwbdeequiv
et_cwbcinstattr = lt_cwbcinstattr
EXCEPTIONS
corrupt_data_file = 1
incompatible_versions = 2
OTHERS = 3.
PERFORM cal_obj_data_bin_size USING lt_object_data_bin CHANGING lv_unzipped_size.
WRITE: / 'uncompressed size: (byte): ' , lv_unzipped_size.
BREAK-POINT.
ENDFORM.
FORM cal_obj_data_bin_size USING it_obj_data TYPE cwbci_t_objdelta CHANGING iv_total_size TYPE i.
DATA(lo_tab_type) = CAST cl_abap_tabledescr( cl_abap_typedescr=>describe_by_name( 'CWBCI_T_OBJDELTA' ) ).
DATA(lo_line_type) = CAST cl_abap_structdescr( lo_tab_type->get_table_line_type( ) ).
lt_comp = lo_line_type->components.
LOOP AT it_obj_data ASSIGNING FIELD-SYMBOL(<obj_data_bin>).
PERFORM calculate_line_size USING <obj_data_bin> CHANGING iv_total_size.
ENDLOOP.
ENDFORM.
FORM calculate_line_size USING is_line_data TYPE cwbciobjdelta CHANGING iv_total_size TYPE i.
DO.
ASSIGN COMPONENT sy-index OF STRUCTURE is_line_data TO FIELD-SYMBOL(<data>).
IF sy-subrc <> 0.
EXIT.
ENDIF.
READ TABLE lt_comp ASSIGNING FIELD-SYMBOL(<line_type>) INDEX sy-index.
CASE <line_type>-type_kind.
WHEN cl_abap_typedescr=>typekind_char OR cl_abap_typedescr=>typekind_num.
iv_total_size = iv_total_size + strlen( <data> ) * 2.
WHEN cl_abap_typedescr=>typekind_xstring.
iv_total_size = iv_total_size + xstrlen( <data> ).
WHEN OTHERS.
ASSERT 1 = 0.
ENDCASE.
ENDDO.
ENDFORM. Once executed, the report will download the note as a compressed binary stream, display the size of this compressed stream and then uncompress it, allow you to view the building block of the note in detail. In the end the size of uncompressed data is displayed as well. Take note 2184333 for example, around 137 KB is downloaded and after it is decompressed, the size inflates to around 742 KB.
Please note that this tool just gives you a draft estimation about the static size of note. The runtime overhead for memory management against deep data object such as internal table and string are not considered.
Note building blocks
The decompressed content of note is actually a xml file and could be parsed by function module SCWN_NOTE_UNPACK_XML
et_cwbnthead
Note header data. See below picture to find how the note header information is maintained in exporting parameter et_cwbnthead of FM SCWN_NOTE_UNPACK_XML.
et_cwbntstxt
Note tilte in multi language.
et_htmltext
Contains note body in html format in multi language. Content for each language is stored in a single line.
et_cwbntdata
Contains note body in multiple language. Content of each language is stored in a seperate internal table.
et_cwbntvalid
Contains note validity information. In this information, component key: 16929, we can find its description from table CWBCMPNT. And 63 for BBPCRM.
And how to understand DEALEID_V 244 for BBPCRM? From this table we can know “244” represents 713.
detailed code delta change contained in variable LV_CODE_DELTA_BIN
The area below marked with blue rectangle is the code delta change our customer could see in the note browser, and the red area is part of variable lv_code_delta_bin inspected via XML Browser. The delta code change consists of two parts: deletion of keyword “IMPORTING”; insertion of two lines “it_customer_h = it_customer_h” and “IMPORTING”. From the picture we can see clearly that the code fragment for insertion or deletion has corresponding XML tag ( I prefer to call it as “directive” ) maintained so that the node tool can know WHAT operation should be performed on these fragment. Meanwhile the context ( line number 38 ) is also known so that node tool can also know WHERE the delta change should be applied.
