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EVERYTHING YOU WANT TO KNOW ABOUT Sx ( BUT WERE AFRAID TO ASK ) PART I

EVERYTHING YOU WANT TO KNOW ABOUT Sx ( BUT WERE AFRAID TO ASK ) PART I. Jim Poole. NASTY STATEMENTS. "Never use the Find Sorted By" "Never use a non descriptor search" "Read logical is always faster than a Find" "Histogram is always faster than a Find" "Never use Finds"

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EVERYTHING YOU WANT TO KNOW ABOUT Sx ( BUT WERE AFRAID TO ASK ) PART I

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  1. EVERYTHING YOU WANT TO KNOW ABOUT Sx ( BUT WERE AFRAID TO ASK ) PART I Jim Poole

  2. NASTY STATEMENTS "Never use the Find Sorted By" "Never use a non descriptor search" "Read logical is always faster than a Find" "Histogram is always faster than a Find" "Never use Finds" "Never . . . , Always . . . " THE HOW, WHY, WHAT . . .

  3. OUTLINE -BASICS OF ADABAS COMMAND PROCESSING A. DETERMINING THE SEARCH ALGORITHM B. PROCESSING THE SEARCH ALGORITHMS C. DETERMINING THE SORT ALGORITHM D. PROCESSING THE SORT ALGORITHMS E. STORAGE OF THE RESULTANT LIST -PROCESSING THE RESULTANT LIST -QUICK NOTE ON READ LOGICAL AND HISTOGRAM PROCESSING -WHAT NATURAL DOES -WHAT ADABAS DOES

  4. PROGRAM ADALINK • DETERMINE DBID • DETERMINE CMD TYPE • CREATE ADABAS USERID • CALL ADABAS SVC/ ROUTER • DB ID TABLE ADABAS • BUILD CQE • MOVE UB TO NAB BASICS OF ADABAS COMMAND PROCESSING

  5. CMD.Q. NC=20-200 THREADS NT=5-30 TBQ WORK POOL CQE SELECT USR-CID-INFO LS= LQ=20-400K TBI LWP=1-5M USER.Q USR-CID-INFO NU=200-3000 LI=20-100K ? Timeout ? ? Rsp.Code? Usr Resources ASSO DATA WORK FCB UI MI BLKSIZE=5064 BLKSIZE=5724 BLKSIZE=2544 BASICS OF ADABAS COMMAND PROCESSING (CONT.) PART 2 REC NI PART 3 AC

  6. BASIC ADABAS CALL/COMMAND (CMD) CB (CONTROL BLOCK) – Eg. CMD / FNR / DB / RSP.CD / LENGTHS / ISN / ISNQ / CID / options FB (FORMAT BUFFER) – FIELDS TO RETURN/UPDATE (+FORMATs) RB (RECORD BUFFER) – FIELD VALUES SB (SEARCH BUFFER) – DESCRIPTORS, RELATIONSHIPS,(+FORMATs) VB (VALUE BUFFER) – DESCRIPTOR VALUES IB (ISN BUFFER) – ISN’S (USE IS OBSCURE)

  7. BASICS OF ADABAS COMMAND PROCESSING (CONT.) NATURAL FIND (combo of): S1/4 - Create ISN list based on search criteria (SB/VB) S2 - Same as S1 but with sort based on DE’s in CB S8 - Combine of ISN lists based on Command ID’s in CB (similar to S1): AND / OR / NOT S9 - Sort of ISN list based on DE’s in CB. (similar to S2) L1/4 - Return records based on ISN’s in ISN list. NATURAL READ LOGICAL: L3/6 NATURAL HISTOGRAM: L9 NATURAL RELEASE /END.LOOP: RC

  8. BASICS OF ADABAS COMMAND PROCESSING (CONT.) THE BASIC Sx. RETURNS: ISQ - ISN QUANTITY (NUMBER OF RECS ON LIST). ISN - OF 1ST RECORD MEETING CRITERIA. (opt) 1ST REC - (opt) S4, PUT 1ST RECORD ON HOLD, (opt) COPT1=R FOR RSP.CD. 145 (opt) ISN LIST - RECORDS MEETING CRITERIA, USES CID.

  9. NATURAL CID: 12200101 1220 Statement no. 01 Pgm. Level no. 01 counter BASICS OF ADABAS COMMAND PROCESSING (CONT.) COMMAND ID (CID): 4b, non-zero, non-blank, Labels ISN List REQUIRED FOR: L1/4 GET NEXT PROCESSING RETAIN ‘SET-NAME’ COPT1=H USE IN SUBSEQUENT Sx COMMANDS NOT REQUIRED: ISQ 1ST RECORD OPTION,COP1/2=I RELEASE PREVIOUS CID Eg.

  10. A. DETERMINING THE SEARCH ALGORITHM • B. PROCESSING THE SEARCH ALGORITHMS • C. DETERMINING THE SORT ALGORITHM • D. PROCESSING THE SORT ALGORITHMS • E. STORAGE OF THE RESULTANT LIST

  11. DETERMINING THE SEARCH ALGORITHM COMPLEX: 2 or more DEs, with more than 2 Values SIMPLE: anything else 1. ADALINK: BASED ON PERIOD IN SB ( > 9) SB=ST. (simple) SB=ST,D,NM. (simple) SB=ST,D,NM,GT. (complex) SB=ST,GT. (simple) ? SB=ST,20,A,GT. ? ? SB=ST,20,A .? 2. COMPLEX COMMANDS ARE NOT SELECTED FROM CQ IF: a. LESS THAN 50% OF WORK-2 IS AVAILABLE. ! SUPERSIZE WORK-2 ! b. LESS THAN LS= AVAILABLE IN WORK POOL. ! SIZE LWP/LS RATIO ! c. AT LEAST ONE Sx IS SUSPENDED WAITING ON LWP SPACE. ! SIZE LWP/LS RATIO ! 3. FINAL SEARCH ALGORITHM IS DETERMINED ONCE COMMAND IS IN AN ADABAS THREAD. . . 4. NOTE THAT ALL S2,S8,S9 COMMANDS ARE FLAGGED COMPLEX.

  12. 1 1 DESCRIPTOR 1 VALUE NM. CT1. NM,20,A. NM,EQ. 2 1 DESCRIPTOR MANY VALUES NM,GE. NM,LT. NM,NE. NM,20,A,GT. NM,S,NM. NM,S,NM,N,NM. NM,O,NM. 7 n DEs, 1 VALUE, OR NM,R,ST. 3 2-5 DESCRIPTORS 1 VALUE EACH, AND NM,D,ST. NM,D,ST,10,A,D,CT. 4 2 OR MORE DEs MANY VALUES NM,D,ST,GT. NM,S,NM,D,ST,O,ST. NM,D,ST,Y,ST,O,ST,Y,ST,S,ST. 5 ALL NON-DEs WT. WT,S,WT. WT,D,HT,GT. (WT and HT are not Descriptors) 6 MIX OF NON-DEs AND DE’S NM,D,WT. DETERMINING THE SEARCH ALGORITHM (cont.) ONCE IN A THREAD:SB/FDT ANALYSIS ALG. DESCRIPTION SEARCH BUFFER EXAMPLES NOTE a: ALG. 5/6 WILL RECEIVED RSP 68 IF ADARUN NONDES=YES. b: (CID), SET-NAME FROM PREVIOUS FIND, TREATED AS 1 DE

  13. A. DETERMINING THE SEARCH ALGORITHM • B. PROCESSING THE SEARCH ALGORITHMS • C. DETERMINING THE SORT ALGORITHM • D. PROCESSING THE SORT ALGORITHMS • E. STORAGE OF THE RESULTANT LIST

  14. PROCESSING THE SEARCH ALGORITHMS: ALG.1 • 1 DE , 1 VALUE NO LWP/LS USED, NO WORK-2 USED VALUE QTY ISNs … SMITH (6) 2,6,8,12,20 … NI R.I.L.* 2,6,8,12,20 SB=NM. • READ FCB-UI-MI-NI. • MOVE NI ISNs TO FINAL LIST. • (ALREADY SORTED) COMMENTS: 1. !VERY FAST, EFFICIENT ! *R.I.L.: RESULTANT ISN LIST

  15. PROCESSING THE SEARCH ALGORITHMS: ALG.2 • 1 DE , MANY VALUES LWP/LS USED, NO WORK-2 USED UI MI NI . . .GLAN GRAN GRUN HURT INGO . .GLAN(3)20,40,50 GLEN(2)12,24 HURT(600)14,15, . . . HUSH(2)3,16 GRAN(600) 2,9, . . . INGO(800) 22,42, . . . GRUN(1)23 HUN(500) 5,27 . . . LWP= 20,40,50 12,24 2,9, . . . 23 5,27,. . . 14,15 . . 3,16 22,42,.. LS= 2,3,5,9,12,14,15, 16,20,22,23,24, 27,40,42,50,. . . 2,3,5,9,12,14,15,16,20,22,23,24,27,40,42,50, . . . R.I.L. SB=NM,GT.

  16. PROCESSING THE SEARCH ALGORITHMS: ALG. 2 cont. • 1 DE , MANY VALUES LWP/LS USED, NO WORK-2 USED • READ FCB-UI-MI. • DO MI-ESTIMATION. IF ISNs > LS/8, THEN ALGORITHM 4. • (EG. LS=40,000, EST. > 5000, THEN ALG. 4) • READ NI, MOVE ISN’S TO ½ LS. • SORT ISNs TO SECOND ½ LS. • MOVE ISNs TO FINAL LIST. COMMENTS: 1. ISNs ARE ALWAYS SORTED (NOTE SEQ. VS. L3/6) 2. ! DE OR DE IS FAIRLY EFFICIENT ! 3. DE-THRU-DE OR DE-RANGE DEPENDS ON NUMBER OF ISNS

  17. PROCESSING THE SEARCH ALGORITHMS: ALG.3 • 1 DE : 1 VAL., 1 DE : 1 VA., . . . NO LWP/LS USED, NO WORK-2 USED SB=NM,D,ST,D,CT. 1. READ FCB-UI-MI-NI FOR @ DE-VALUE (UP TO 5 DEs) 2. READ ALONG ISN LISTS IN BLOCKS. 3. MOVE ISNs IN COMMON TO RESULTANT ISN LIST. NI(NM) SMITH(20) 2,4,6,8,9,10,. . . NI(ST) UTAH(15) 3,4,5,8,10,. . . PROVO(33) 1,4,5,6,10,. . . NI(CT) R.I.L. 4,10, . . . COMMENTS 1. ! VERY EFFICIENT !

  18. PROCESSING THE SEARCH ALGORITHMS: ALG.4 >= 2 DEs, > 2 VALUES USE LWP/LS, MAY USE WORK-2 SB=NM,D,ST,GT. MI NI NI UI MI NI NI NI LWP= W-2 WORK LS= WORK-2 • ISNs • ISN BIT STRINGS W-2 W-2 W-2 R.I.L.

  19. PROCESSING THE SEARCH ALGORITHMS: ALG.4 cont. ALG.4: ANY NON NON-DE SB THAT IS NOT ALG. 1,2,3,7 1.ALLOCATE LS: MIN(LS, TOPISN/8 + TOPISN/128) 2.READ FCB-UI-MI FOR EACH PART OF QUERY ( D IS SEPARATOR) 3.SEQUENCE EACH PART IN SMALLEST TO LARGEST ORDER (MI EST.) 4.READ NI FOR EACH PART, CREATE BIT STRINGS (8 ISNs / BYTE) 5.MERGE BIT STRINGS 6.IO TO WORK-2 IF NEEDED. 7.CONVERT BIT-STRING BACK TO ISNs, CREATE RESULT ISN LIST. COMMENTS 1. SIZE LS TO ASSIST COMPLEX SEARCHES (eg. LS=200K for 15M recs) 2. ! SEQUENCE QUERY FROM LEAST TO MOST LIKELY ! 3. SOME ARE GOOD, SOME ARE BAD, IT DEPENDS: AGE>75 AND NAME=‘SNODGRASS’ SEX=F AND HEIGHT>2 (meters) 4. ! EVALUATE EACH QUERY BASED ON CURRENT & FUTURE DATA ! ! BEST WHEN EACH CRITERIA IS LIMITING AND RESULT IS SMALL !

  20. DS DS DS REC1 REC2 REC3 . . . RECn RECm RECl . . . RECp RECq RECr . . . WT=? : : : WORK LWP= LS= ISN BIT STRINGS ISNs WORK 2 R.I.L. COMMENTS ! SOLVES A VERY SMALL CLASS OF PROBLEMS ! PROCESSING THE SEARCH ALGORITHMS: ALG.5 ALL NON-DEs USE LWP/LS, MAY USE WORK-2 SB=WT. 1. READ ALL RECS IN DS, EVALUATE AGAINST CRITERIA. 2. CREATE BIT STRING OF VALID ISNs IN LS/LWP. 3. IF NEEDED SPOOL TO WORK-2. 4. CONVERT BIT STRING TO ISNs. 5. WRITE TO RESULTANT ISN LIST.

  21. WORK WORK 3 1 5 12 15 : : AC AC AC DS DS DS WT=? WT=? WT=? : : : : : : : : : R.I.L. 5,15,. . . PROCESSING THE SEARCH ALGORITHMS: ALG.6 DEs AND NON-DEs MAY USE LWP/LS, MAY USE WORK-3 SB=NM,D,WT. 1.SEPARATE SB BETWEEN DE/NON-DE CRITERIA. 2.DO ALG.1,2,3,4,7 ON DE CRITERIA. 3.WRITE TEMP ISN LIST TO WORK-3 4.READ WORK-3 ISN-LIST, FOR EACH: a. READ REC: AC-DS b. EVALUATE AGAINST NON-DE CRIT. 5.IF CRITERIA MET, WRITE ISN TO FINAL RESULTANT ISN LIST. ALG.1,2,3,4,7

  22. PROCESSING THE SEARCH ALGORITHMS: ALG.6 CONT. • COMMENTS • GOOD FOR ONE-TIME SEARCHES. • GOOD IF INITIAL TEMP ISN LIST IS SMALL (RECS STILL IN LBP=), • AND NON-DE CRITERIA FURTHER RESTRICTS LIST. NATURAL: NON-DE MARKED AS N IN DDM FOR DE FIELD

  23. PROCESSING THE SEARCH ALGORITHMS: ALG.7 2 OR MORE DEs, 1 VALUE EACH, OR USE WORK-3 SB=NM,R,CT. 1.READ FCB-UI-MI-NI FOR EACH DE. 2.WRITE ISNs TO WORK-3. (?) 3.MERGE ISNS, CREATE RESULTANT ISN LIST. ADA V5.3 COMMENTS: 1. FAIRLY EFFICIENT.

  24. A. DETERMINING THE SEARCH ALGORITHM • B. PROCESSING THE SEARCH ALGORITHMS • C. DETERMINING THE SORT ALGORITHM • D. PROCESSING THE SORT ALGORITHMS • E. STORAGE OF THE RESULTANT LIST

  25. DETERMINING THE SORT ALGORITHM ADABAS SORTS ARE IN MEMORY ONLY: LIMITED BY ADARUN LS= (20K-200K) ELSE RESPONSE CODE 1 2 TYPES OF SORT COMMANDS S2 - CONTAINS ALG 1-7 SEARCH TO CREATE R.I.L. SORT ON 1-3 DEs SORT ASCENDING/DESCENDING S9 - R.I.L. PASSED IN IB(RARE) OR BY COMMAND-ID SORT ON 1-3 DEs SORT ASCENDING ONLY SORT ALGORITHMS: 1, 2 TRY 2 FIRST, 1 SECOND.

  26. DETERMINING THE SORT ALGORITHM cont. IF ( ISNQ ) * 2 * ( 4 + LEN.DE1 + LEN.DE2 + LEN.DE3 ) > (ADARUN LS=) THEN ALGORITHM 1 ELSE ALGORITHM 2 EXAMPLE. LS=100,000 LENGTH.DE=21 ISNQ * 2 ( 4 + 21) >? 100,000 ISNQ * 50 >? 100,000 ISNQ >? 20,000 ! NOTE THAT MANY SORTS ARE ALG.2, NOT ALG.1 !

  27. LWP= DS DS DS DS AC AC AC AC 2-BUTTE 1-PARIS 9-BUTTE 8-AKRON LS= 1-PARIS 2-BUTTE 8-AKRON 9-BUTTE . . . . R.I.L. 1 2 8 9 . . . 8-AKRON 2-BUTTE 9-BUTTE 1-PARIS . . . . : : : : : : R.I.L. 8,2,9,1,. . . . PROCESSING THE SORT ALGORITHMS: ALG.2 SB=NM. CB ADDS1=CT

  28. PROCESSING THE SORT ALGORITHMS: ALG.2 CONT. 1.START WITH THE RESULTANT ISN LIST FROM THE SEARCH. 2.FOR EACH ISN ON THE LIST READ AC-DS FOR THE RECORD. 3.MOVE THE ISN-DE.VALUE PAIR TO ½ OF LS=. 4.AFTER ALL PAIRS MOVED TO LS=, SORT INTO SECOND ½ OF LS=. 5.CREATE FINAL RESULTANT ISN LIST. COMMENTS: WORST CASE IO: ISNQ * (AC + DS) IF ISNQ SMALL, THEN AC/DS REMAIN IN BUFFER POOL FOR L1/4’s ! FOR SMALL LISTS, VERY EFFICIENT ! ! FOR LARGE LISTS, LOTSA AC/DS IO ! COMPARE: S1 SB=NM,GT. S2 SB=NM,GT. CB.ADDS1=NM

  29. UI R.I.L. MI 1 2 8 9 . . . NI . . .AKRON-8 . . . BUTTE-2,9, . . . PARIS-1 . . . 1 2 3 LWP= ISNcntr 1 2 8 9 :: 3 8-1, 2-2, 9-2, 1-3, . . . 2 LS= 1 2 R.I.L. 8,2,9,1,. . . . PROCESSING THE SORT ALGORITHMS: ALG.1 SB=NM. CB ADDS1=CT Cntr:

  30. PROCESSING THE SORT ALGORITHMS: ALG.1 cont 1.START WITH THE RESULTANT ISN LIST FROM THE SEARCH. MOVE R.I.L. INTO ½ LS=. 2.READ THE UI-MI-NI INDEX FOR EACH SORT-DE, KEEP A COUNTER FOR HITS. 3.AS EACH ISN IS FOUND IN THE NI, UPDATE LS=, ADD 1 TO COUNTER. 4.ONCE ALL ISNs FOUND, SORT INTO SECOND ½ OF LS=. 5.CREATE FINAL RESULTANT ISN LIST. COMMENTS: -NI SCAN WILL BE FASTER IF ALL ISN’S FOUND EARLY. -IF 1 ISN HAS HIGHEST SORT-DE VALUE, ENTIRE NI WILL BE READ ! EG. ISNQ=10, CB.ADDS1=SS (SUPER-DE), ISN-X HAS SS= ‘ZZ*’ NI/UI IS 1,000,000 BLOCKS ! 1 MILLION BLOCKS WILL BE READ !

  31. 3. MAX ISNQ THAT CAN BE SORTED BEFORE RSP.CD. 1: 1 DE2 DE3 DE TOPISN < 65536 LS/12 LS/16 LS/20 TOPISN >= 65536 LS/14 LS/20 LS/26 PROCESSING THE SORT ALGORITHMS: ALG.1 cont ? WHEN RESPONSE CODE 1 ? 1. VERIFY ADARUN LS= WITH DPARM Eg. LS=20,000 ACTUAL=19,968 LS=100,000 ACTUAL=999,840 2. VERIFY TOPISN OF FILE (NOT ISN QTY). >< 65,536 ? 4. EXAMPLE: ADARUN LS=120,000 S2 1 DE: ISNQ=10,000 S2 2 DE: ISNQ= 7,500 S2 3 DE: ISNQ= 6,000

  32. A. DETERMINING THE SEARCH ALGORITHM • B. PROCESSING THE SEARCH ALGORITHMS • C. DETERMINING THE SORT ALGORITHM • D. PROCESSING THE SORT ALGORITHMS • E. STORAGE OF THE RESULTANT LIST

  33. WORK TBI, ADARUN LI= NSISN=51 USRB-CID1 USRB CID=1 ISQ=7 …1,2,3,4,5,6,7. USRB CID=2 ISQ=100 USRB-CID2 …1,2,3,. . .,51 52,53,. . .,100 USRC CID=1 ISQ=100 C1=H USRC-CID1 …1,2,3,. . .,51 1,2,3,. . .,100 …1. USRD CID=1 ISQ=1 C1=H USRD-CID1 STORAGE OF THE RESULTANT LIST FUNCTION OF: CID / ADARUN NSISN= / COP1=H (RETAIN SET) USRA CID=1 ISQ=1 USRA CID=0 ISQ=100 Pt. III

  34. STORAGE OF THE RESULTANT LIST PROCESSING THE RESULTANT LIST FIRST RECORD RETURNED IF FBL / RBL SPECIFIED. THAT IS FORMAT-BUFFER-LENGTH > 1 COMMON TO MOST FINDs : S1, S2, S4, S8 ,S9

  35. PROCESSING THE RESULTANT LIST L1/4 GET NEXT PROCESSING TBI LI= WORK FIND Sx L1 L1 L1 . . . LOOP RC …1,4,5,6,.. 55,56,. . . 1. Sx CREATES RESULTANT ISN LIST, RETURNS ISNQ AND 1ST RECORD. 2. EACH L1 ACCESSES TBI ELEMENT FOR NEXT ISN, READS AC-DS FOR RECORD. IF TBI ELEMENT EXHAUSTED, WORK-3 BLOCK IO. 3. LOOP ISSUES AN RC.

  36. 68 – NON-DESCR NOT ALLOWED NONDES= 70 – TBI FULL NSISN= LI= RELEASE set-name 73 – WORK 3 FULL WORKSIZE CACHE WORK 3 RELEASE set-name MANAGE ISNQTY 74 – WORK 2 FULL LWKP2= CACHE WORK 2 REVIEW COMPLEX SEARCHES 46 – TOO MANY CIDs PER USER NQCID= RELEASE set-name 7 – Sx TIME EXCEEDED TLSCMD= REVIEW BAD SEARCHES ADABAS RESPONSE CODES FOR Sx PROCESSING RSP.CODE DATABASE PROGRAM

  37. QUICK NOTE ON READ LOGICAL AND HISTOGRAM PROCESSING READ LOGICAL: L3/6 HISTOGRAM: L9 READ LOGICAL L3 : L3 L3 : . . . LOOP RC TBQ ADARUN LQ= UI USR-CID-PTR MI USR-CID-PTR NI AC HISTOGRAM L9 : L9 L9 : . . . LOOP RC DS-RECS 1.INITIAL CALL CREATES TBQ ELEMENT. 2.EACH CALL ACCESSES TBQ FOR PTR, UI-MI-NI (L9) UI-MI-NI-AC-DS (L3/6) 3.LAST CALL RECEIVES RSP.CD. 3 4.END.LOOP ISSUES RC.

  38. Response 175 Explanation: Aninconsistencywas detected between the index and Data Storage. Action: Run the "check" utilities (especially ADAICK and ADAVAL) against the file, and contact your Software AG technical support representative. PER MESSAGES AND CODES MANUAL (NEW TO 7.4): “ UNDER V7.4 SOME CMDS, THE VALUE IN THE INDEX IS CHECKED AGAINST THE VALUE IN DATA STORAGE. IF THEY DO NOT MATCH, A RC 175 IS RETURNED.” ADABAS V7.4 DIRTY READ CHECK L3,L6, some S1/4

  39. ADABAS V7.4 DIRTY READ CHECK • REQUIRED FOR ADABAS CLUSTER SERVICES • INTEGRITY CHECK FOR NON-CLUSTER DATABASES • SEE ADABAS SPEC ZAP AY743109 TO DISABLE

  40. USE OF CID/GFID NOT A FACTOR USE OF IBL NOT A FACTOR ADABAS V7.4 DIRTY READ CHECK DIRTY READ CHECK MADE FOR ALL L3/L6 (READ LOGICAL) DIRTY READ CHECK MADE FOR Sx ONLY IF: • CMD = S1 OR S4 • AND • FBL>1 (RETURN 1ST REC) • AND • 3. SB= 1 Descr • OR • SB= 1 Descr thru 1 Descr

  41. ADABAS V7.4 DIRTY READ CHECK LOGIC: 1. IF ELEMENTARY DE, DATA STORAGE RECORD SCANNED UNTIL DE-FIELD FOUND. 2. IF SUB/SUPER/HYPER DE, ENTIRE RECORD SCANNED (LOCATE ALL SOURCE FIELDS). 3. CONSIDER: SB=DE. FB /= DE. ? SCAN OF RECORD UNTIL ?

  42. DAS ENDE

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