Welcome to:

IMS Database Performance
Rick Long, IMS Level 2 Database Support
Team
Silicon Valley Lab
ricklong@au1.ibm.com...
Disclaimer
© Copyright IBM Corporation 2009. All rights reserved.
U.S. Government Users Restricted Rights - Use, duplicati...
Abstract
It is every DBA's nightmare – Does the database
need to be reorganized or tuned?

This session describes
the key ...
Example
HALDB stats from 2008
HALDB stats from 2005
Partition name

Roots

Segments

Roots

Segments

Additions

ECDBP01

...
Agenda
• Review of Database types
– Full Function Database
• HDAM,HIDAM

– HALDB
• PHDAM, PHIDAM,PSINDEX

• Reorganization...
HIDAM
• Hierarchic Indexed Direct Access Method
KEY

• 2 databases
• Index
• Data

KSDS

INDEX
DATA

– 2 access method com...
HDAM
• Hierarchic Direct Access Method
KEY

– 1 database
• Data

RANDOMIZER

– 2 access methods

KEY

• OSAM
• ESDS (VSAM)...
HALDB
• High Availability Large Data Base
– Access methods
• PHDAM Partitioned HDAM
• PHIDAM Partitioned HIDAM

– Secondar...
Common Record Structure
• Record Structure
ROOT

DEP

DEP

– Prefix
– Segment

DEP

DEP

DEP

• Variable length
• Fixed le...
Current Structure for R1CUST
CUSTOMER

DISTRICT

CUSTLOCN

ADDRLINE

CUSTINV

CUSTORDN

PAYMENTS

Data set group 3

Data s...
IMS Database Pointers

© Copyright IBM Corporation 2013

5.2
IMS Pointers
• HALDB
SEGMENT
PREFIX
SC DB PTF PTB PCF LCF

LCF

DATA (BYTES=)

LOGICAL CHILD FIRST(28 BYTES)
PHYSICAL CHIL...
IMS Pointers
• HALDB
SEGMENT
PREFIX
SC DB PTF PTB PCF

LCF

LCF

ILK

DATA (BYTES=)

INDIRECT LIST KEY
LOGICAL CHILD FIRST...
COURSE

COURSE

COURSE

CLASS

PTF Pointers
PTB Pointers
INSTRUCT

EDUC

STUDENT

EXPR
PTR=T
PTR=TB
PTR=NT

© Copyright IB...
Physical Child Pointer Specification
COURSE

COURSE

COURSE

CLASS

PCF Pointers
Twin Forward Pointers

EDUC

INSTRUCT

ST...
Reorganization Objectives

© Copyright IBM Corporation 2013

5.2
Reorganization Objectives
• Access segments
– Fewest I/Os
– Segment placement

• Database records
– optimal number of bloc...
Reorganization Requirements
• Information about the current state of the DB
– Regular Statically Information gathering
• H...
Reorganization Reasons
• Getting Segments into the Most Desirable block
• Re-sequence Segments
– Root segments into Sequen...
“Mean time” to Reorganization
• How long do I want to go between
reorganizations
• What are the reasons I need to reorg?
–...
Most Desirable Block
• HDAM/PHDAM Root
– Block it Randomizes to
– Rap Chain stays within the block
– Ideal length of Rap c...
Most Desirable Block
• HIDAM/PHIDAM Root
– PTR=TB - In the block with the next highest key value
– PTR=NT - In the block w...
HIDAM ROOT Physical Twin PTR
KEY

400000

COURSE

RBA
RBA

999999

COURSE

RBA

200100

CALL :ISRT

RBA

200000

MDB

POIN...
HIDAM ROOT Physical Twin PTR
KEY

400000

COURSE

RBA
RBA

999999

COURSE

RBA

200020

CALL :ISRT

RBA

200000

MDB

POIN...
Most Desirable Block
• Child Segment
– Sequential key – Lowest key value
• Block with its parent
– Sequential key - not lo...
Physical Child Pointer Specification
• Sequential key defined on child segment
– ISRT for child segment
• Inserting the lo...
Physical Child Pointer Specification
• Sequential key defined on child segment
– ISRT for child segment
• Inserting the ke...
HD space search algorithm
1.
2.
3.
4.

In the most desirable block
In the second-most desirable block or CI.
In any block ...
Reorganization “How Tos”

© Copyright IBM Corporation 2013

5.2
How Do I Tune a: HDAM
• Size of the RAA
• Packing Density
– Packing Factor = bytes of data / bytes in RAA
• General usage ...
How Do I Tune a: HIDAM
• Keep Free space in it.
– Don’t let heavy insert activity all end up at the end of
the data set.

...
How Do I Tune a: HALDB
• NEVER
• Tune those PARTITIONS which need to be.
• Change of mind set from a database to a PARTITI...
How Do I Tune : VSAM
• Change the V to an O - Make it OSAM
• Faster access method
• OSAM Sequential buffering
– BMP readin...
How Do I Tune : Split Segments
• CI free space in the block
• Full length is used for comparison with bitmap
data for inse...
How Do I Tune : Split Segments

0VL SEGMENT SPLIT STATISTICS
--------------------------SEGMENT
<----------- PREFIX AND
SC ...
How Do I Tune : Long twin chains
• CI free space in the block
• Data Set Group
– Long segment
– Left in Hierarchy
– How ma...
Current Structure for TxCUST
CUSTOMER

DISTRICT

CUSTLOCN

ADDRLINE

CUSTINV

CUSTORDN

© Copyright IBM Corporation 2013

...
How Do I Tune Data Set Groups

DBD

Elapse
time in
Mins
CPU SECS

S1CNTPY O1CNTPY
PHIDAM PHIDAM
1DSG
1DSG
5PARTS
1PARTS

2...
How Do I Tune : Processing Sec Index
(whole DB)

JOB name
S1ORDLS1
S1ORDLS2
U1ORDLS1
U1ORDLS2
P1ORDLS1
P1ORDLS2
O1ORDLS1
O...
Long Twin Chains

CUST

ORDER

PROD

PROD
Segment B

invoice

PROD

ORDER

PROD

PROD

INVOICE

PROD

INVOICE

PROD

INVOI...
Long Twin Chains

CUST

ORDER

PROD

PROD
Segment B

invoice

INVOICE

PROD

ORDER

PROD

PROD

INVOICE

INVOICE

PROD

PR...
Long Twin Chains

CUST

ORDER

PROD

PROD
Segment B

PROD

PROD

PROD

PROD

PROD

PROD

PROD

PROD

PROD

PROD

PROD

PRO...
Long Twin Chains

CUST

ORDER

INVOICE

PROD

PROD
Segment B

ORDER

ORDER

INVOICE

PROD

PROD

INVOICE

ORDER

INVOICE

...
IMS Database Performance

QUESTIONS?
ricklong@au1.ibm.com

© Copyright IBM Corporation 2013
Welcome to:

HPPC Reports

@Copyright IBM Corporation 2013

5.2
Text Slide
0DBNAME: C1CUST DB#: 001 PARTNAME: C1CUST7 PART ID: 00007 REORG#:00002 DSG#:A DDNAME:C1CUST7A
DSNAME: RLONG.IMS...
Text Slide

DSNAME: RLONG.IMS10.C1CUST.C1CUST7.A00007
BLK# 0........1.........2.........3.........4.........5.........6......
Text Slide

0DISTRIBUTION OF DEPENDENT SEGMENTS IN ROOT BLOCK
#ROOTS WITH 00 DEPS
=
2
#ROOTS WITH 12 DEPS
=
0
#ROOTS WITH ...
Text Slide
0DISTRIBUTION OF DEPENDENT SEGMENTS BY SEGMENT CODE
-------------------------------------------------0SEGM CODE...
DATABASE RECORD STATISTICS

SEGMENT <---- SEGMENT LENGTH ---> <-AVERAGE OCCUR-> AVG LGTH CUMULATIVE
SC LV DG NAME
OCCUR PR...
VL SEGMENT SPLIT STATISTICS

SC NAME
-- -------03 CUSTORDN
-- -------TOTALS

TYPE OCCUR NOT
SPLIT
SPLIT SAME BLOCK NOT IN ...
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IMS Database Performance - IMS UG Singapore 8-2013

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Transcript of "IMS Database Performance - IMS UG Singapore 8-2013"

  1. 1. Welcome to: IMS Database Performance Rick Long, IMS Level 2 Database Support Team Silicon Valley Lab ricklong@au1.ibm.com @Copyright IBM Corporation 2013 5.2
  2. 2. Disclaimer © Copyright IBM Corporation 2009. All rights reserved. U.S. Government Users Restricted Rights - Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. THE INFORMATION CONTAINED IN THIS PRESENTATION IS PROVIDED FOR INFORMATIONAL PURPOSES ONLY. WHILE EFFORTS WERE MADE TO VERIFY THE COMPLETENESS AND ACCURACY OF THE INFORMATION CONTAINED IN THIS PRESENTATION, IT IS PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. IN ADDITION, THIS INFORMATION IS BASED ON IBM’S CURRENT PRODUCT PLANS AND STRATEGY, WHICH ARE SUBJECT TO CHANGE BY IBM WITHOUT NOTICE. IBM SHALL NOT BE RESPONSIBLE FOR ANY DAMAGES ARISING OUT OF THE USE OF, OR OTHERWISE RELATED TO, THIS PRESENTATION OR ANY OTHER DOCUMENTATION. NOTHING CONTAINED IN THIS PRESENTATION IS INTENDED TO, NOR SHALL HAVE THE EFFECT OF, CREATING ANY WARRANTIES OR REPRESENTATIONS FROM IBM (OR ITS SUPPLIERS OR LICENSORS), OR ALTERING THE TERMS AND CONDITIONS OF ANY AGREEMENT OR LICENSE GOVERNING THE USE OF IBM PRODUCTS AND/OR SOFTWARE. IBM, the IBM logo, ibm.com, IMS, IBM High Performance Pointer Checker for z/OS and CICS are trademarks or registered trademarks of International Business Machines Corporation in the United States, other countries, or both. If these and other IBM trademarked terms are marked on their first occurrence in this information with a trademark symbol (® or ™), these symbols indicate U.S. registered or common law trademarks owned by IBM at the time this information was published. Such trademarks may also be registered or common law trademarks in other countries. A current list of IBM trademarks is available on the Web at “Copyright and trademark information” at www.ibm.com/legal/copytrade.shtml Other company, product, or service names may be trademarks or service marks of others. © Copyright IBM Corporation 2013
  3. 3. Abstract It is every DBA's nightmare – Does the database need to be reorganized or tuned? This session describes the key performance indicators and how to interpret the large volume of information provided by the IBM HPPC utility. © Copyright IBM Corporation 2013
  4. 4. Example HALDB stats from 2008 HALDB stats from 2005 Partition name Roots Segments Roots Segments Additions ECDBP01 100,467 574,731 100,467 576,357 1,626 ECDBP02 81,687 581,307 81,687 583,377 2,070 ECDBP03 49,113 293,427 124,261 684,172 390,745 ECDBP04 249 2,140,708 309 6,662,891 4,522,183 ECDBP05 142 1,335,117 161 4,301,836 2,966,719 ECDBP06 180 1,300,517 182 3,745,620 2,445,103 ECDBP07 192 1,780,635 194 5,129,972 3,349,337 ECDBP08 123 1,479,159 123 4,616,059 3,136,900 4,071,069 2,692,959 ECDBP09 186 1,378,110 194 ECDBP10 257 1,875,931 258 6,850,596 4,974,665 6,406,064 4,822,559 ECDBP11 581 1,583,505 779 ECDBP12 415 382,060 1,418 1,641,717 1,259,657 1,301,952 820,438 ECDBP13 74 481,514 113 ECDBP14 1,476 978,823 1,604 2,482,972 1,504,149 2,915,532 1,824,578 ECDBP15 2,119 1,090,954 2,305 ECDBP16 1,992 331,247 2,251 1,047,040 715,793 332,103 302,605 ECDBP17 378 29,498 840 ECDBP18 149 2,767 149 2,767 0 TOTAL 239,780 17,620,010 317,295 53,343,096 35,723,086 © Copyright IBM Corporation 2013
  5. 5. Agenda • Review of Database types – Full Function Database • HDAM,HIDAM – HALDB • PHDAM, PHIDAM,PSINDEX • Reorganization Needs – What factors cause a need for Reorganization © Copyright IBM Corporation 2013
  6. 6. HIDAM • Hierarchic Indexed Direct Access Method KEY • 2 databases • Index • Data KSDS INDEX DATA – 2 access method combinations • KSDS/ESDS (VSAM/VSAM) PRIMARY • KSDS/OSAM (VSAM/OSAM) – – – – ESDS / OSAM 'Native-mode' index Unique root keys required Pointers Space reusable © Copyright IBM Corporation 2013
  7. 7. HDAM • Hierarchic Direct Access Method KEY – 1 database • Data RANDOMIZER – 2 access methods KEY • OSAM • ESDS (VSAM) – – – – – ESDS / OSAM Randomizer Non-unique root keys allowed Synonyms Pointers Space reusable © Copyright IBM Corporation 2013
  8. 8. HALDB • High Availability Large Data Base – Access methods • PHDAM Partitioned HDAM • PHIDAM Partitioned HIDAM – Secondary Index • PSINDEX Partitioned Secondary Index – Partitions • Key Range • Partition Selection Exit 301 .. 400 201 .. 300 101 .. 200 1 .. 100 – Partition Selection before randomize – each partition can be different © Copyright IBM Corporation 2013
  9. 9. Common Record Structure • Record Structure ROOT DEP DEP – Prefix – Segment DEP DEP DEP • Variable length • Fixed length © Copyright IBM Corporation 2013
  10. 10. Current Structure for R1CUST CUSTOMER DISTRICT CUSTLOCN ADDRLINE CUSTINV CUSTORDN PAYMENTS Data set group 3 Data set group 2 © Copyright IBM Corporation 2013 ADJSMNTS
  11. 11. IMS Database Pointers © Copyright IBM Corporation 2013 5.2
  12. 12. IMS Pointers • HALDB SEGMENT PREFIX SC DB PTF PTB PCF LCF LCF DATA (BYTES=) LOGICAL CHILD FIRST(28 BYTES) PHYSICAL CHILD FIRST(4 BYTES) PHYSICAL TWIN BACKWARD(4 BYTES) PHYSICAL TWIN FORWARD(4 BYTES) DELETE BYTE(FF), Prefix Descriptor(FP) SEGMENT CODE © Copyright IBM Corporation 2013
  13. 13. IMS Pointers • HALDB SEGMENT PREFIX SC DB PTF PTB PCF LCF LCF ILK DATA (BYTES=) INDIRECT LIST KEY LOGICAL CHILD FIRST(28 BYTES) PHYSICAL CHILD FIRST(4 BYTES) PHYSICAL TWIN BACKWARD(4 BYTES) PHYSICAL TWIN FORWARD(4 BYTES) DELETE BYTE(FF), Prefix Descriptor(FP) SEGMENT CODE © Copyright IBM Corporation 2013
  14. 14. COURSE COURSE COURSE CLASS PTF Pointers PTB Pointers INSTRUCT EDUC STUDENT EXPR PTR=T PTR=TB PTR=NT © Copyright IBM Corporation 2013
  15. 15. Physical Child Pointer Specification COURSE COURSE COURSE CLASS PCF Pointers Twin Forward Pointers EDUC INSTRUCT STUDENT EXPR Physical child pointers are stored on the parent, but defined on the SEGM for the child: PCF ONLY: PCF ONLY: PCF, PCL: SEGM NAME=. . . ,PARENT=. . . SEGM NAME=. . . ,PARENT=((. . . ,SNGL)) SEGM NAME=. . . ,PARENT=((. . . ,DBLE)) © Copyright IBM Corporation 2013
  16. 16. Reorganization Objectives © Copyright IBM Corporation 2013 5.2
  17. 17. Reorganization Objectives • Access segments – Fewest I/Os – Segment placement • Database records – optimal number of blocks • Blocks/ Cis – Free space – In RAA (Root Addressable Area) – Room in the data set © Copyright IBM Corporation 2013
  18. 18. Reorganization Requirements • Information about the current state of the DB – Regular Statically Information gathering • HPPC (or equalivant) • Unload/Reload stats • Historical information for Trend analysis • Information on how the DB is used – Sequential processing vs. Random access – Mass insert or delete processing – Heavy sequential BMP processing – Which DBs are most frequently accessed – Which DBs are most frequently updated • Splitting of segments – Variable length segments – Compressed segments © Copyright IBM Corporation 2013
  19. 19. Reorganization Reasons • Getting Segments into the Most Desirable block • Re-sequence Segments – Root segments into Sequence – Child segment twin chains into a block • HDAM Tuning – Getting Root segments into HOME block – Reducing Rap chain lengths • Larger RAA (Root Addressable Area) • Rap chain out of the block • Unspliting Split segments • Refreshing Free space in the data set • “Mean time” to reorganization © Copyright IBM Corporation 2013
  20. 20. “Mean time” to Reorganization • How long do I want to go between reorganizations • What are the reasons I need to reorg? – Re-sequencing segments – Split segments – Long twin chains – Rap chains in too many blocks © Copyright IBM Corporation 2013
  21. 21. Most Desirable Block • HDAM/PHDAM Root – Block it Randomizes to – Rap Chain stays within the block – Ideal length of Rap chain is the number of DB records which will fit in the block • All roots in RAA © Copyright IBM Corporation 2013
  22. 22. Most Desirable Block • HIDAM/PHIDAM Root – PTR=TB - In the block with the next highest key value – PTR=NT - In the block with the next lowest key value – PTR=T - HIDAM Root (T) • SHOULD NEVER be used as RAPs are used and causes DELETE performance issues – Overflow not relevant © Copyright IBM Corporation 2013
  23. 23. HIDAM ROOT Physical Twin PTR KEY 400000 COURSE RBA RBA 999999 COURSE RBA 200100 CALL :ISRT RBA 200000 MDB POINTER 100000 PTR=TB RBA COURSE COURSE In the block with the next highest key value © Copyright IBM Corporation 2013
  24. 24. HIDAM ROOT Physical Twin PTR KEY 400000 COURSE RBA RBA 999999 COURSE RBA 200020 CALL :ISRT RBA 200000 MDB POINTER 100000 PTR=NOTWIN RBA COURSE COURSE In the block with the next lowest key value © Copyright IBM Corporation 2013
  25. 25. Most Desirable Block • Child Segment – Sequential key – Lowest key value • Block with its parent – Sequential key - not lowest value • In the block with the next lowest key value – NOTWIN - Block with parent – Rules • FIRST – Block with parent • LAST - Block with previous LAST twin • HERE - Block positioned on © Copyright IBM Corporation 2013
  26. 26. Physical Child Pointer Specification • Sequential key defined on child segment – ISRT for child segment • Inserting the lowest key value • Child PTF set to the next highest key value (taken from PCF) • MDB – block with parent CLASS INSTRUCT STUDENT © Copyright IBM Corporation 2013
  27. 27. Physical Child Pointer Specification • Sequential key defined on child segment – ISRT for child segment • Inserting the key that is not the lowest key value • Inserted in sequence and PTF set to next highest key (taken from PTF) • MDB – block with next lowest key value CLASS INSTRUCT STUDENT © Copyright IBM Corporation 2013
  28. 28. HD space search algorithm 1. 2. 3. 4. In the most desirable block In the second-most desirable block or CI. In any block or CI in the buffer pool on the same cylinder. In any block or CI on the same track, as determined by consulting the bitmap. (longest segment type defined. Uncompressed from DBD LENGTH=) 5. In any block or CI on the same cylinder, as determined by consulting the bitmap. 6. In any block or CI in the buffer pool within plus or minus n cylinders. Specify n in the SCAN= keyword in the DATASET statement in the DBD. For HALDB databases, the value of the SCAN= keyword is always 0. 7. In any block or CI plus or minus n cylinders, as determined by consulting the bitmap. 8. In any block or CI in the buffer pool at the end of the data set. 9. In any block or CI at the end of the data set, as determined by consulting the bitmap. The data sets will be extended as far as possible before going to the next step. © Copyright IBM Corporation 2013
  29. 29. Reorganization “How Tos” © Copyright IBM Corporation 2013 5.2
  30. 30. How Do I Tune a: HDAM • Size of the RAA • Packing Density – Packing Factor = bytes of data / bytes in RAA • General usage guidelines was 70% • High Insert Less then 70% • Mostly read - 80% • Put a “P” in front – Make it PHDAM – Reduce Packing density to suit how long between reorgs. – If data comes and goes, you can reorg very infrequently © Copyright IBM Corporation 2013
  31. 31. How Do I Tune a: HIDAM • Keep Free space in it. – Don’t let heavy insert activity all end up at the end of the data set. • CI free space for dependent segments • CA free space for Root and dependents © Copyright IBM Corporation 2013
  32. 32. How Do I Tune a: HALDB • NEVER • Tune those PARTITIONS which need to be. • Change of mind set from a database to a PARTITION – Review partition information – Reorg partitions independent of the others • Exceptions – Re-partitioning – STILL ONLY Deal with PARTITIONS and as few a possible © Copyright IBM Corporation 2013
  33. 33. How Do I Tune : VSAM • Change the V to an O - Make it OSAM • Faster access method • OSAM Sequential buffering – BMP reading a HIDAM data base in root sequence © Copyright IBM Corporation 2013
  34. 34. How Do I Tune : Split Segments • CI free space in the block • Full length is used for comparison with bitmap data for insert • HDAM – lower packing density © Copyright IBM Corporation 2013
  35. 35. How Do I Tune : Split Segments 0VL SEGMENT SPLIT STATISTICS --------------------------SEGMENT <----------- PREFIX AND SC NAME TYPE OCCURS NOT SPLIT SPLIT -- -------- ---- ------ ------------ ---------------03 CUSTORDN FC 400 0 0.0 % 200 050.0 % -- -------- ---- ------ ------------ ---------------TOTALS 400 0 0.0 % 200 050.0 % DATA -----------> IN SAME BLOCK NOT IN SAME BLOCK --------------- -------------------100 50.0 % 100 50.0 % --------------- -------------------100 50.0 % 100 50.0 % 0VL SEGMENT SPLIT STATISTICS --------------------------SEGMENT <----------- PREFIX AND SC NAME TYPE OCCURS NOT SPLIT SPLIT -- -------- ---- ------ ------------ ---------------03 CUSTORDN FC 202 0 0.0 % 202 100.0 % -- -------- ---- ------ ------------ ---------------TOTALS 202 0 0.0 % 202 100.0 % DATA -----------> IN SAME BLOCK NOT IN SAME BLOCK --------------- -------------------6 3.0 % 196 97.0 % --------------- -------------------6 3.0 % 196 97.0 % © Copyright IBM Corporation 2013
  36. 36. How Do I Tune : Long twin chains • CI free space in the block • Data Set Group – Long segment – Left in Hierarchy – How many other segments does it displace for their MDB? – After reorg, Twins might be in a single block • Large block size © Copyright IBM Corporation 2013
  37. 37. Current Structure for TxCUST CUSTOMER DISTRICT CUSTLOCN ADDRLINE CUSTINV CUSTORDN © Copyright IBM Corporation 2013 PAYMENTS ADJSMNTS
  38. 38. How Do I Tune Data Set Groups DBD Elapse time in Mins CPU SECS S1CNTPY O1CNTPY PHIDAM PHIDAM 1DSG 1DSG 5PARTS 1PARTS 2.24 15.19 2.25 14 © Copyright IBM Corporation 2013 U1CNTPY PHIDAM 3DSG 5PARTS 0.37 7.49 P1CNTPY PHIDAM 1DSG 1PART 2.24 14.03
  39. 39. How Do I Tune : Processing Sec Index (whole DB) JOB name S1ORDLS1 S1ORDLS2 U1ORDLS1 U1ORDLS2 P1ORDLS1 P1ORDLS2 O1ORDLS1 O1ORDLS2 Elaspe time in No of Order mins CPU SEC segms No of GN 33.19 484.15 5,668,280 5,338,196 4.23 83.04 5,668,280 5,338,196 37.13 575.09 5,668,060 5,668,281 4.23 97.27 5,668,060 5,668,281 33.43 497.83 5,668,060 5,668,061 4.48 87.46 5,668,060 5,668,061 35.49 523.12 5,668,145 5,668,146 3.48 94.66 5,668,145 5,668,146 © Copyright IBM Corporation 2013
  40. 40. Long Twin Chains CUST ORDER PROD PROD Segment B invoice PROD ORDER PROD PROD INVOICE PROD INVOICE PROD INVOICE PROD INVOICE PROD INVOICE PROD ORDER PROD INVOICE PROD INVOICE ORDER PROD INVOICE PROD PPOD INVOICE PROD INVOICE © Copyright IBM Corporation 2013
  41. 41. Long Twin Chains CUST ORDER PROD PROD Segment B invoice INVOICE PROD ORDER PROD PROD INVOICE INVOICE PROD PROD PROD PROD INVOICE INVOICE PROD PROD PROD INVOICE ORDER PROD PROD PROD INVOICE PPOD ORDER PROD PROD INVOICE ORDER PAYMENT PAYMENT PAYMENT PAYMENT SHIP SHIP SHIP SHIP © Copyright IBM Corporation 2013 INVOICE INVOICE
  42. 42. Long Twin Chains CUST ORDER PROD PROD Segment B PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PROD PPOD PROD PROD PROD PROD PROD PROD PROD PPOD PROD PROD PROD PROD © Copyright IBM Corporation 2013
  43. 43. Long Twin Chains CUST ORDER INVOICE PROD PROD Segment B ORDER ORDER INVOICE PROD PROD INVOICE ORDER INVOICE PROD PROD ORDER INVOICE PROD PROD PROD PROD PROD PROD PROD PROD INVOICE PAYMENT PAYMENT PAYMENT PAYMENT SHIP SHIP SHIP SHIP PROD © Copyright IBM Corporation 2013 PPOD
  44. 44. IMS Database Performance QUESTIONS? ricklong@au1.ibm.com © Copyright IBM Corporation 2013
  45. 45. Welcome to: HPPC Reports @Copyright IBM Corporation 2013 5.2
  46. 46. Text Slide 0DBNAME: C1CUST DB#: 001 PARTNAME: C1CUST7 PART ID: 00007 REORG#:00002 DSG#:A DDNAME:C1CUST7A DSNAME: RLONG.IMS10.C1CUST.C1CUST7.A00007 DBORG: PHIDAM INTERVAL: START BLOCK 1 END BLOCK 359 --------------- BASE -------------- ------------ OVERFLOW ------------ SC SEGNAME OCCURRENCES SPLIT-PRFX SPLIT-DATA OCCURRENCES SPLIT-PRFX 01 02 03 04 05 06 CUSTOMER DISTRICT CUSTORDN CUSTINVN PAYMENTS ADJUSTMT TOTALS -NOTE : 2000 0 0 3997 0 0 34 34 0 34 0 0 0 0 0 0 0 0 ---------- ---------- ---------6065 34 0 - VIRTUAL SEGMENTS ARE NOT SHOWN 0 0 374 782 0 0 ---------1156 © Copyright IBM Corporation 2013 0 0 374 0 0 0 ---------374 SPLIT-DATA 0 0 408 0 0 0 ---------408
  47. 47. Text Slide DSNAME: RLONG.IMS10.C1CUST.C1CUST7.A00007 BLK# 0........1.........2.........3.........4.........5.........6.........7.........8.........9.........0 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890 1 0 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 100 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 200 0000000000001111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 300 11111111111111111111111111111111111111111111111111111111111 -BLOCKS W/O SPACE = 212 BLOCKS WITH SPACE = 147 NO OF BIT MAPS = 1 © Copyright IBM Corporation 2013
  48. 48. Text Slide 0DISTRIBUTION OF DEPENDENT SEGMENTS IN ROOT BLOCK #ROOTS WITH 00 DEPS = 2 #ROOTS WITH 12 DEPS = 0 #ROOTS WITH 01 DEPS = 4 #ROOTS WITH 13 DEPS = 0 #ROOTS WITH 02 DEPS = 1960 #ROOTS WITH 14 DEPS = 0 #ROOTS WITH 03 DEPS = 0 #ROOTS WITH 15 DEPS = 0 #ROOTS WITH 04 DEPS = 34 #ROOTS WITH 16 DEPS = 0 #ROOTS WITH 05 DEPS = 0 #ROOTS WITH 17 DEPS = 0 #ROOTS WITH 06 DEPS = 0 #ROOTS WITH 18 DEPS = 0 #ROOTS WITH 07 DEPS = 0 #ROOTS WITH 19 DEPS = 0 #ROOTS WITH 08 DEPS = 0 #ROOTS WITH 20 DEPS = 0 #ROOTS WITH 09 DEPS = 0 #ROOTS WITH 21 DEPS = 0 #ROOTS WITH 10 DEPS = 0 #ROOTS WITH 22 DEPS = 0 #ROOTS WITH 11 DEPS = 0 #ROOTS WITH 23 DEPS = 0 #ROOTS WITH 24+ DEPS = 0 ---------------------------------------------------------------------------------#ROOTS IN THE DATA SET = 2000 © Copyright IBM Corporation 2013
  49. 49. Text Slide 0DISTRIBUTION OF DEPENDENT SEGMENTS BY SEGMENT CODE -------------------------------------------------0SEGM CODE #DEPIN #DEPIN PERCENTAGE SEGMENT CODE #DEPS IN PERCENTAGE ROOTBLK ALLBLK (ROOT/ALL) ROOT BLOCK ALL BLOCKS (ROOT/ALL) ----------- --------------------- ------ --------(SEGCODE 02 ) 3992 3997 99.87 (SEGCODE 13 ) N / A N / A N / A (SEGCODE 03 ) 34 408 8.33 (SEGCODE 14 ) N / A N / A N / A (SEGCODE 04 ) 34 816 4.16 (SEGCODE 15 ) N / A N / A N / A (SEGCODE 05 ) N / A N / A N / A (SEGCODE 16 ) N / A N / A N / A (SEGCODE 06 ) N / A N / A N / A (SEGCODE 17 ) N / A N / A N / A (SEGCODE 07 ) N / A N / A N / A (SEGCODE 18 ) N / A N / A N / A (SEGCODE 08 ) N / A N / A N / A (SEGCODE 19 ) N / A N / A N / A (SEGCODE 09 ) N / A N / A N / A (SEGCODE 20 ) N / A N / A N / A (SEGCODE 10 ) N / A N / A N / A (SEGCODE 21 ) N / A N / A N / A (SEGCODE 11 ) N / A N / A N / A (SEGCODE 22 ) N / A N / A N / A (SEGCODE 12 ) N / A N / A N / A (SEGCODE 23 ) N / A N / A N / A (SEGCODE 24+) N / A N / A N / A ---------- ---- ----- ------------------ ------ --------#DEPS IN THE DS 4060 5221 77.76 © Copyright IBM Corporation 2013
  50. 50. DATABASE RECORD STATISTICS SEGMENT <---- SEGMENT LENGTH ---> <-AVERAGE OCCUR-> AVG LGTH CUMULATIVE SC LV DG NAME OCCUR PRFX + DATA = TOTAL P/ROOT PER/PRNT DB RECORD LENGTH -- -- -- -------- ----- --- ------- ------ ----- -------------------01 01 A CUSTOMER 2,000 38 130.0 168.0 1.0 168.0 168.0 02 02 A DISTRICT 3,997 18 62.0 80.0 2.0 2.0 159.9 327.9 03 02 A CUSTORDN 408 18 220.2V 238.2 0.2 0.2 48.6 376.5 04 02 A CUSTINVN 816 18 55.0 73.0 0.4 0.4 29.8 406.3 05 02 A PAYMENTS 0 18 25.0 43.0 0.0 0.0 0.0 406.3 06 02 A ADJUSTMT 0 18 56.0 74.0 0.0 0.0 0.0 406.3 -- -- -- -------- ----- --- --------------- -------------------TOTALS 7,221 AVERAGE DB RECORD LENGTH = 406.3 AVERAGE DB RECORD PREFIX LENGTH = 85.0 © Copyright IBM Corporation 2013
  51. 51. VL SEGMENT SPLIT STATISTICS SC NAME -- -------03 CUSTORDN -- -------TOTALS TYPE OCCUR NOT SPLIT SPLIT SAME BLOCK NOT IN BLOCK ---- ---- ---- ---- ---------------------------- ------------FC 408 0 0.0% 408 100.0 % 14 3.4 % 394 96.6 % ---- --- ----- ---- ------------ ---------------- --------- ----408 0 0.0% 408 100.0 % 14 3.4 % 394 96.6 % © Copyright IBM Corporation 2013
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