Transcript What’s New in DB2 9 for z/OS - IBM

IBM Global Technology Services
IBM Global Services
What’s New in DB2 9 for z/OS
2009. 05. 14
Soohee Lee([email protected])
시스템 서비스 사업본부
IBM Global Technology Services
IBM Global Technology Services
Agenda
 DB2 9 for z/OS
 Synergy with System z
 Scalability
 Availability
 Data sharing
 Application Enhancements
 Utilities
 Performance
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DB2 9 for z/OS
pureXML
SOA Enablement
Optimistic locking for WebSphere
LOB performance, usability
More online schema changes
Workload
Consolidation
Online REBUILD INDEX
Parallel Sysplex clustering improvements
Index compression
Simplification
Reduced TCO
Partition By Growth tables
Cloned tables
Many SQL improvements
Dynamic
Warehousing
New built-in OLAP expressions
Histogram statistics
Optimization Server Center
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Synergy with System z
 DB2 9 for z/OS
Synergy with System z
 Scalability
 Availability
 Data sharing
 Application Enhancements
 Utilities
 Performance
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IBM System z10 Benefits for DB2
Faster CPU, more CPU, more memory
•50% more n-way performance “on average”
•62% more uniprocessor performance
•70% more server capacity (54->64 CPUs)
•Up to 64 CPUs, z/OS 1.9 needed for 64-way in a single LPAR
•Up to 1.5TB, z/OS 1.8 needed for > 256G in a single LPAR
Infiniband Coupling Facility links
New OSA-Express3, 10 GbE for faster remote apps
HiperDispatch
Hardware Decimal Floating Point facility
1MB page size (DB2 X plans to exploit)
50+ instructions added to improve compiled code efficiency (DB2 X plans to
use)
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DB2 & IBM zIIP value
portions of DB2 for z/OS V8 and DB2 9(blue) workloads may benefit from zIIP*:
ERP, CRM, Business Intelligence or other enterprise applications
• Via DRDA over a TCP/IP connection (enclave SRB, not stored procedure or
UDFs)
• DB2 9 for z/OS Remote native SQL procedure
• DB2 9 XML paring
New Specialty
Engine
Data warehousing application*: Large parallel SQL queries
 DB2 9 higher percentage of parallel queries eligible for zIIP
 DB2 utilities LOAD, REORG & REBUILD (maintaining index structures)
zIIP allows a program working with z/OS to have all or a portion of its enclave Service Request Block(SRB) work
direction to zIIP. Above types of DB2 work are those running in enclave SRBs, of which portions can be sent to zIIP.
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zIIP Enabling
 zIIP Software
• z/OS V1R8 기반 (운영체제 기능에 기본 내장)
• z/OS V1R6-V1R7
FMIDs : R6 – JBB77S9 / R7 – JBB772S
SPE for SDSF (APAR PK18215) / RMF (APAR OA13499)
• DB2 V9.1 기반 (소프트웨어 기능에 기본 내장)
• DB2 V8
DRDA : PK18454
Utilities : PK19920
Parallel Query / Star Join – PK19921
zIIP projection
• SYS1.PARMLIB (IEAOPTxx) : PROJECTCPU=YES
• determine how much work can be offloaded to the zIIP (without zIIP)
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Scalability
 DB2 V9.1 for z/OS
 Synergy with System z

Scalability
 Availability
 Data Sharing
 Application Enhancements
 Utilities
 Performance
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DB2 9 64 bit Evolution (Virtual Storage Relief)
Virtual Storage Constraint in an important issue for many DB2 customers.
 EDMPOOL Changes:
•V8 - DBD storage moved above 2GB bar.
•DB2 9 - SKCT, SKPT some CT, PT storage
moved aboved 2GB bar.
•DB2 9 approx. 60% reduction in below-the-bar
storage EDMPOOL size observed for lab
workloads.
 Other changes :
•Some storage acquired for distributed
application moved above 2GB bar.
•Control blocks for table spaces and RTS move
aboved the bar.
•Control block structures for dynamic SQLrelated storage
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Automated memory monitoring
 Built-in monitor runs from startup to shutdown and checks the health of the
system at one-minute intervals.
 DBM1 storage below the bar is monitored for critical storage increases.
•If the DBM1 storage below the bar reaches specific thresholds of 88, 92,
96, or 98 percent
•Then issue messages (DSNV508I, DSNV510I, DSNV511I, and
DSNV512I)
• Report current DBM1 storage consumption and indicate the agents that
are consuming the most storage.
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64-bit DDF - Shared Private Storage with DBM1
 DDF address space runs in 64-bit addressing mode
• Shared 64-bit memory object avoids cross memory moves between DBM1
and DDF and improve performance.
 Shared memory : new virtual storage
type allowing multiple address spaces
to share storage.
 Similar to ECSA - always addressable,
avoids XM moves.
Different from ECSA - only available to
those address spaces registering with
z/OS to shared this storage.
Reduces data formatting and data
movement.
Reduces virtual storage
•It exists once, instead of in each
address space
•Set by HVSHARE in
PARMLIB(IEASYSxx)
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•DISPLAY VIRTSTOR,HVSHARE
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WLM assisted Buffer Pool management
 WLM-assisted buffer pool
management
• ALTER BUFFERPOOL ()
AUTOSIZE(YES)
DBM1
Data Collection
DB2 Periodic Report
• z/OS 1.8
Buffer Pool Sizes
Hit Ratio for Random Reads
• DB2 registers BP to WLM
and reports synch read I/O
delays to WLM
BP0
• DB2 periodically reports
BP hit stats to WLM
Bufferpool Adjustment
+ - 25%
• WLM projects effect of
adjusting BP size on
workload performance
goals
•WLM drives DB2 exit to
adjust size if appropriate
DB2 9 restricts to
+/- 25%
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WLM
1 Plots size and
hit ratio over
time.
2 Projects effects
of changing
the size
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NOT LOGGED Table spaces
 ALTER / CREATE TABLESPACE as NOT LOGGED
• ALTER not allowed if in same UOW with an update to the table space
 Reduce logging in situations where is not required.
 Turn ON/OFF logging during the heavy insert or update activity.
 Effects the UNDO / REDO records
• Control information is still logged.
 A Unit of Recovery (UR) is still created
 Indexes, LOB and XML inherit the logging attribute of the base
LOG YES is a synonym for LOGGED
LOG NO is a synonym for NOT LOGGED
Recommendation:
Don’t sacrifice recovery for minor performance gain.
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Universal Table Spaces
 Combination of segmented with partitioning options
• improved space management
• improved mass delete performance
 2-types of partitioning
• Partition by RANGE (PBR)
 Key range partitioning that we’ve always had
• Partition by GROWTH (PBG)
 New partitions are added as data grows
 Single table only (1 TABLE / 1 TABLESPACE)
 DROP / CREATE to migrate existing page sets
 Simple table spaces can not be created
• Default table space is now Segmented
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Universal Table Spaces (PBR & PBG)
 UTS - Partition by range (PBR)
• This is no difference to Version 8 (and prior) partitioning
• A UTS PBR is created just like a normal partitioned table space
• But with a SEGSIZE clause
 UTS - Partition by growth (PBG)
•Starts off as one partition table space
•As data is inserted/loaded the partition will fill up
•When it is full, another partition is automatically created
No -904
No partitioning key
•You specify the limit to the number of partitions on the CREATE/ALTER
table space statement
MAXPARTITIONS
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Variable-Length Column Improvements
 Regardless of the order of columns in a CREATE TABLE statement
 Physically, the fixed length columns will be first
 Followed by the variable length ones
• This is known as Reordered Row Format (RRF)
• As opposed to Basic Row Format (BRF)
 Reordered Row Format (RRF)
 The performance of RRF is SO much better than BRF
 This is NOT optional
 Once you are in New Function Mode this is the only way
• For every CREATE TABLE
• And after every REORG or LOAD REPLACE
 Reduce the impact and overhead of processing variable-length
columns.
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Indexing Enhancements
 Larger index pages
•8K /16K /32K page
•Fewer page splits for long keys
•More key values per page
Index compression
•Reduce the storage consumed by large
index (like as DW Application)
•CREATE/ALTER INDEX COMRESS
YES/NO
•No compression dictionaries
•Only compress the data in leaf pages
•Data is compressed to 4K pages on disk
•32K/16K/8K pages results in up to 8x/4x/2x
disk savings
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Indexing Enhancements
 Asymmetric Index Page Splits
Index split roughly 50/50 (prior to DB2 9)
Asymmetric Index page split in DB2 9
Sequential inserts into the middle of an
index resulted in some pages with 50%
free space
New algorithm dynamically
accommodates a varying pattern of
inserts
Improve space utilization and reduce
contention that results from frequent page
splits in a index with sequential insert
patterns
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Indexing Enhancements
 RANDOM index key
• Avoid hot spots with multiple processes inserting sequential keys
• Reduce contention of index page P-lock
•Trade-off between contention relief and additional Getpage, read/write
I/O
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Native SQL Procedure
 Run entirely within DB2 and do not require a WLM stored procedure AS
 Eliminates the cross address space overhead between the DBM1 and WLM
stored procedure AS as well as the round-trip between Workload Manager
and DBM1
 eligible for ZIIP if invoked from DRDA/TCPIP connections
Native SQL Procedural
Language
•Fully integrated into
the DB2 engine
•Eliminates generated
C code and compilation
• An SQL procedure
created without
FENCED or
EXTERNAL is a native
SQL procedure
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DB2 Trace Filtering

New filtering capabilities for –START TRACE that INCLUDE or EXCLUDE
based on these keywords:
•USERID -- client userid
WRKSTN -- client workstation name
APPNAME -- client application name
PKGLOC -- package LOCATION name
PKGCOL -- package COLLECTION name
PKGPROG -- PACKAGE name
CONNID -- connection ID
CORRID -- correlation ID

In V8 , only PLAN, AUTHID, LOCATION
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Availability
 DB2 V9.1 for z/OS
 Synergy with System z
 Scalability

Availability
 Data Sharing
 Application Enhancements
 Utilities
 Performance
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CLONE Tables
Fast way to replace table contents
Eliminate outage for LOAD REPLACE
CLONE are created with an ALTER statement
•ALTER TABLE ADD CLONE clone-table-name
•UTS only
A CLONE inherits ALL of the attributes of the base table
•Including all indexes, constraints, triggers
•Structures ONLY - not data
CLONE has a different INSTANCE number to the base object.
•VCAT.DSNDBC.ddd.ppp.I0002.Annn
CLONE and base table can be used independently
•For SQL
•For Utilities (new CLONE keyword, except RUNSTATS)
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CLONE Tables
EXCHANGE DATA BETWEEN syntax
•Drain & switch
•DB2 switches the instance numbers in the catalog
•This is FAST
Very like a switch phase
Before EXCHANGE
Base-table
clone-table
After EXCHANGE
Base-table
clone-table
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Recovery to point in time with consistency
Prior to DB2 V8, if point-in time recovery, consistency is not ensured.
(If the point is not consistency point)
In DB V9 , Full data consistency
Occurs for TOLOGPOINT & TORBA - not for TOCOPY
Uncommitted URs will be rolled back
Reduce need for QUIESCE points
After LOGAPPLY , new 2 phase (LOGSCR,LOGUNDO)
LOGSCR : Analyzes log records and constructs information about inflight, indoubt, inabort, and postponed abort units of recovery.
LOGUNDO : Rolls back any uncommitted changes that the active
units of recovery made to the recovered objects.
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APPEND Table
 CREATE / ALTER TABLE APPEND YES/NO
 Ignore clustering during SQL inserts and online LOAD processing
 Rows are appended at the end of the table or appropriate partition
 You can insert or online LOAD your data quickly and regain the clustering
order later by running REORG.
Benefit !!:
TABLE
•Maximizes performance for “INSERT at end”
•Avoids overhead of attempting
to preserve clustering sequence
INSERT or
Online LOAD
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REFRESH for EARLY code
 Modify early code without IPL
 New command
• REFRESH DB2,EARLY
• Member-scope
•The command is rejected if the DB2 subsystem is already active.
•The EARLY code can only be properly updated when DB2 is not active
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RENAME INDEX & RENAME COLUMN
Change object characteristics without need to drop and recreate the object.
 RENAME INDEX
• RENAME INDEX source-index-name TO new-index-name
• Does not change OBID
• Plan and package will not be invalidated
 RENAME COLUMN
• ALTER TABLE tablename RENAME COLUMN old-col TO new-col
• Invalidation of any plan or package that is dependent on the table
• Auto Rebinding occurs
• Scenario1 : no reference the renamed column
 Rebind will be successful
• Scenario2 : reference the renamed column
Rebind will not be successful
Must modify, recompile and rebind your application
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Log truncation by timestamp
 Conditional restart log truncation by timestamp
 New parameters on CRESTART CREATE
 ENDTIME
 SYSPITRT (SYSTEM LEVEL RECOVERY MODE)
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Ability to cancel “DB command”
 Ability to cancel “database command” that have been issued from the
console.
• -STOP
DB(DSN0170) SP(TESTIMP*) command with some other thread
• -DIS THD(*) TYPE(SYSTEM)
•You can issue, -CANCEL THD(93) for command or system agent.
• After CANCEL, You can issue -START DB command to change status STOPP to RW.
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Migration and Fallback Path
 With DB2 9 , you can always drop back to the previous stage
 Cannot fallback to V8 after entry to DB2 9 (ENFM), but can fallback to DB2
9 (CM*)
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Data Sharing
 DB2 V9.1 for z/OS
 Synergy with System z
 Scalability
 Availability

Data Sharing
 Application Enhancements
 Utilities
 Performance
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Data Sharing Enhancement
Log latch contention relief
Restart performance enhancement
•Reduced impact of retained lock - Allowing table level retained locks
•Open data sets ahead of log apply
Remove GBP-dependency at object level by command
•ACCESS DB MODE(NGBPDEP)
•Typical usage would be before batch run
Open dataset ahead of use via command
•Available to pre-open or prime the data set
•ACCESS DB MODE(OPEN) [PART]
Auto-recover GRECP/LPL objects on group restart
•Useful in disaster recovery or GDPS scenarios
Balance group attach connections across multiple members on same LPAR
(round-robin basis)
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SQL
 DB2 V9.1 for z/OS
 Synergy with System z
 Scalability
 Availability
 Data Sharing
 Application Enhancements
 Utilities
 Performance
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MERGE
“Upsert”
•A combination of UPDATE and INSERT, MERGE is a single SQL
operation
•Single row or multi-row
If a row matches the ON condition it is updated,
Otherwise it is inserted
Provides better performance, less interaction across the network, less DB2
and application interaction, and less SQL to code.
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SELECT FROM UPDATE/DELETE/MERGE
 Used to determine the values before or after records
•FINAL TABLE : select from rows after update
•OLD TABLE : select from row before update
•INCLUDE clause
•include a new column to the result table but not add the column to the
target table.
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FETCH FIRST/ ORDER BY in Subselect
 FETCH FIRST and ORDER BY clauses are now allowed in subselects.
 In this example both clauses are used in the subselect as a way to select the
top 10 rows from table T1 as ordered by columns C2 and C1.
INSERT INTO T2
(SELECT C1, C2, C3
FROM T1
FETCH FIRST 10 ROWS ONLY
ORDER BY C2, C1);
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SKIP LOCK DATA in SELECT
SKIP LOCK DATA in SELECT
•Rows with incompatible locks by other transactions are skipped
SQL
data
data
X
data
data
X
X data
data
data
data
• Page or Row lock only
• Reduce lock contention and improve performance
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TRUNCATE
 Very quickly delete all rows from a table
• Simple , Segmented, Partitioned , Universal Tablespaces
• IGNORE delete triggers ,deletes the data WITHOUT firing delete triggers
• Table level deletion (LOAD REPLACE works on tablespace level)
• IMMEDIATE option - operation cannot rolled back
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INTERSECT / EXCEPT
Intersect – Returns the records that two
result sets have in common
•Frequently used in ‘find the duplicates
query’
•Rows from either result set that do not
match are excluded.
Except – Returns the records that are
members of one result set that are not
members of the other
RS1
RS2
Intersect
RS1
RS2
Requirement
•Both result sets must have the same
column structure.
Except
RS1
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RS2
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Index on Expression
 Simple indexes can contain concatenated
column
CREATE INDEX totalPay on
W2_TABLE(salary,bonus)
 Index on expression
•Value of the index has been transformed
•Optimizer can use this index
•Query performance can be enhanced
•Evaluate during insertion time or during
index rebuild
CREATE INDEX totalPay on
W2_TABLE(salary+bonus)
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Built-in Functions (RANK, DENSE_RANK)
 RANK
Generates a row number defining the rank as 1 plus the number of rows
that precede the row.
If two or more rows are not distinct with respect to the ordering, there will
be one or more gaps in the sequential rank numbering. Also referred to
as Olympic Ranking.
DENSE_RANK
Similar to RANK but ensures there are no gaps.
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Built-in Functions (RANK, DENSE_RANK)
 RANK
SELECT SMALLINT(RANK() OVER (ORDER BY score DESC)) as RANK,
athlete, event, score FROM scores;
 DENSE_RANK
SELECT SMALLINT(DENSE_RANK() OVER (ORDER BY score DESC)) AS
DENSE_RANK,athlete, event, score FROM scores;
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Built-in Functions (ROW_NUMBER)
 ROW_NUMBER
•Creates a sequential row number that is computed for each row starting
with 1.
•No number skipping.
SELECT SMALLINT(ROW_NUMBER() OVER (ORDER BY score DESC)) AS
ROW_NUMBER, athlete, score FROM scores ORDER score DESC;
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Time Scalar Functions
TIMESTAMPADD(interval, number, timestamp)
•Returns the result of adding the specified number of the specified interval to
the specified timestamp
•Add 1 year to the current timestamp
SELECT TIMESTAMPADD(256,40,TIMESTAMP('1965-07-27-15.30.00'))
FROM SYSIBM.SYSDUMMY1;
•Returns a value ’2005-07-27-15.30.00.000000’.
•Interval values are 256=years, 128=quarters, 64=months, etc
TIMESTAMP_ISO(expression)
•Returns a timestamp based on a date, a time, or a timestamp expression.
SELECT TIMESTAMP_ISO(DATE(‘1992-02-19’))
FROM SYSIBM.SYSDUMMY1;
•Returns a value ‘1992-02-19-00.00.00.000000’
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Real-Time Statistics Evolution
Real Time Statistics (RTS) have been collected automatically since V7
DB2 9 moves RTS into the Catalog & externalizes the information automatically
•DSNDB06.SYSRTSTS
SYSIBM.SYSTABLESPACESTATS
SYSIBM.SYSINDEXSPACESTATS
•During ENFM processing, the data is moved from user-defined tables to the
new catalog tables
•Drop user-defined tables after ENFM
Gather information about indexes that are used / not used
•SYSINDEXSPACESTATS.LASTUSED
•"Used", as defined by DB2 is the following:
As an access path for query or fetch.
For searched UPDATE / DELETE SQL statement.
As a primary index for referential integrity.
To support foreign key access.
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Plan Stability
New function of DB2 9 (PK52523)
•Protects customers against access path regression
•Allows for a “safe” way to REBIND (fall back)
•Available even in DB2 9 (CM) as it can benefit migration and fallback
•Strongly recommended
•Make sure that the pre-conditioning APAR for Plan Stability (PK52522) is
applied on all V8 (NFM) systems
What is the problem?
•REBINDs can cause access path changes
•Most of the time, this improves query performance …
•… But when it doesn’t
No easy way to undo the REBIND
Can lead to a lot of grief to our customers and to IBM
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Plan Stability...
REBIND PACKAGE …
At REBIND, save old copies of packages
•Catalog tables
•Directory
Two flavors
•BASIC and EXTENDED
•Controlled by new ZPARM PLANMGMT
•Default is OFF
•Also supported as REBIND options
REBIND PACKAGE …
•PLANMGMT(BASIC)
2 copies: Current and Previous
•PLANMGMT(EXTENDED)
3 copies: Current, Previous, Original
Most bind options can be changed at REBIND
•But a few must be the same
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•SWITCH(PREVIOUS)
Switch between current & previous
•SWITCH(ORIGINAL)
Switch between current & original
FREE PACKAGE …
•PLANMGMTSCOPE(ALL) – Free
package completely
•PLANMGMTSCOPE(INACTIVE) – Free
all old copies
Invalidation and Auto rebind
•Each copy invalidated separately
•Auto rebind replaces only the current
copy , previous and original are not
affected
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Plan Stability...
 REBIND ... PLANMGMT(BASIC)
 REBIND ... SWITCH(PREVIOUS)
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Plan Stability...
 REBIND ... PLANMGMT(EXTENED)
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 REBIND ... SWITCH(ORIGINAL)
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Plan Stability...
Sample Strategy for Migration using Plan Stability
Migration strategy with Plan Stability
•Before migrating to DB2 9 (CM), ensure V8 plan table information is available
•On migration to DB2 9 (CM), set ZPARM PLANMGNT to EXTENDED
Objective: Make sure that the V8 version of package is kept as the original in
case a fallback to DB2 V8 is required
Restriction: EXTENDED means that DB2 always keeps 3 versions of the
package (even if they are the same). Watch out for SPT01 growth (limit is still
64GB with DB2 9).
•Delay rebind on DB2 9 (CM) until running stable
Do not rebind on DB2 9 (CM) until RUNSTATS has been run
Make sure new ZPARM STATCLUS=ENHANCED (Default)
Introduces major change to CLUSTERRATIO calculation in DB2 9 and
introduction of new statistic Data Repetition Factor (DRF)
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Plan Stability...
Sample Strategy for Migration using Plan Stability
 REBIND in DB2 9 (CM)
•
•
•
DB2 now stores 3 versions of the package
Initial REBIND
 Current version = DB2 9 version
 Previous version = Original version = V8 version
 If needed because of V9 access path regression, use REBIND PACKAGE
…SWITCH(PREVIOUS) to fallback to the V8 version
Subsequent REBINDs
 Current version = “New” DB2 9 version
 Previous version = Latest DB2 9 version
 Original version = V8 version
 Use REBIND PACKAGE … SWITCH(PREVIOUS) to fallback to the
previous V9 version
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Plan Stability...
Sample Strategy for Migration using Plan Stability
 In case of fallback to DB2 V8, before falling back to V8
•
Use REBIND PACKAGE … SWITCH(ORIGINAL) to fall back to original
version of package (V8 version)
 In the future, to establish a new original version e.g to move forward to the
version after DB2 9
•
Use FREE PACKAGE … PLANMGMTSCOPE(INACTIVE) to free off
the original (will also free off the previous version)
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Two ways to store XML in a Databases
Competitors
DB2 9 Pure XML
create table dept (deptID char(8),…, deptdoc xml);
deptID
…
deptdoc
“PR27”
…
<dept> …
<emp>…</emp>
</dept>
…
…
…
DB2 Storage
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Pure XML in DB2 9
 XML data is stored in XML-typed
columns in tables
create table dept (deptID char(8),…, deptdoc xml);
• XML is stored in a parsed
hierarchical format
• Relational columns are stored in
relational format
• The XML table space inherits the
base table attributes
 SQL/XML constructor functions and
XPath support
 XML Indexing
• improve the efficiency of queries
on XML
 Improve XML performance
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deptID
…
deptdoc
“PR27”
…
<dept> …
<emp>…</emp>
</dept>
…
…
…
DB2 Storage
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Utilities
 DB2 V9.1 for z/OS
 Synergy with System z
 Scalability
 Availability
 Data Sharing
 Application Enhancements

Utilities
 Performance
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IBM Global Technology Services
DB2 9 Utilities Performance Improvement
CPU reduction in LOAD, REORG and REBUILD
 Reductions mostly due to improved index processing (* with exceptions)
 10 to 20% in Image Copy (* even with forced CHECKPAGE YES)
 5 to 30% in load, Reorg, Reorg Partition, Rebuild Index
• Except REORG TABLESPACE SHR CHG PART with NPIs
 20 to 40% in Load
 20 to 60% in Check Index
 35% in Load Partition
 30 to 40% in Runstats Index
 40 to 50% in Reorg Index
 Up to 70% in Load Replace Partition with dummy input
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IBM Global Technology Services
REORG Enhancement
 Elimination of BUILD2 phase
•REORG TS PART SHRLEVEL CHANGE
•NPI also shadowed
•NPI implicitly reorged
•Improved availability
 But concurrent REORGs at part level for same tablespace not
permitted
 REORG parallelism for UNLOAD, RELOAD, LOG phases
• Parallel uload & load of partitions
• Separate concurrent jobs not required
• Improve performance
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IBM Global Technology Services
REORG Enhancement
 Automatic display of blocking claimers for REORG
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Online REBUILD INDEX
 REBUILD INDEX SHRLEVEL CHANGE
 Great for building new non-unique indexes or when index is in RBDP
 Do not use REBUILD INDEX to move the index to a new location.
• use REORG INDEX to move volume
• use REBUILD INDEX SHR CHG to fix a broken or restricted index, or to
build an index after DEFER.
 Tables space must be in LOGGED state (new log phase)
 SHRLEVEL CHANGE is not well suited for unique indexes and concurrent
DML
Inserts and updates of the index will fail with a resource unavailable (-904)
because uniqueness checking cannot be done while the index is in RBDP.
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IBM Global Technology Services
Online CHECK DATA
 CHANGE CHECK DATA works on a copy of the data and indexes (shadows)
 Applications can read from and write to the index, table space, or partition
that is to be checked.
 Improve availability
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UNLOAD SKIP LOCKED DATA
 Skipping locked rows during UNLOAD
• UNLOAD SHRLEVEL CHANGE ISOLATION CS & SKIP LOCKED DATA
• With SKIP LOCKED DATA, the UNLOAD utility can skip rows on which
incompatible locks are held by other transactions.
• Reduce lock contention, improve performance
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MODIFY RECOVERY
 MODIFY RECOVERY simplification and safety
 You can specify
• What you want to delete : DELETE keyword
• What you want to keep : RETAINE keyword (new in V9)
• Improve usability
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IBM Global Technology Services
RECOVER Enhancement
 RECOVER RESTOREBEFORE(RBA OR LRSN)
•When lost the least recent image copy (with TORBA or TOLOGPOINT)
•Tell db2 to not try to allocate the lost image copy but to work with older
copy
 Displaying progress of RECOVER (During LOGAPPLY phase)
-DISPLAY UTILITY result with a new message DSNU116I
Indicates the range of the log that needs to be applied
Show the progress that has been made up to the last commit and the
elapsed time since the start of the log apply phase of the recovery.
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Julian Data and Time in Utility Output
 Julian date and time stamp(local time) in utility output
•Easier to analyze utility runs ,
•Include timestamp with message number in SYSPRINT
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Performance
 DB2 V9.1 for z/OS
 Synergy with System z
 Scalability
 Availability
 Data Sharing
 Application Enhancements
 Utilities
Performance
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IBM Global Technology Services
DB2 9 for z/OS Performance Overview
 DB2 9 z9 and z990 performance plan example
Utilities
Histogram statistics
REBIND
DSNZPARMs
Your situation will vary.
Z800 and z900 expect +5% to +10% CPU
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DB design adjustments
Index Improvements
Application changes
Native SQL procedures
SQL adjustments
IBM Global Technology Services
DB2 9 for z/OS Performance Overview
 Significant CPU time reduction in most utilities
 Synergy with new hardware : zIIP, MIDAW, DS8000,...
 Performance / Scalability Enhancements
• Especially Insert, Update & Delete
 Query / Access Path Performance Enhancements
 Other performance enhancements : LOB, varchar, native SQL
procedure, index compression
 Improve virtual storage usage below 2GB DBM1
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IBM Global Technology Services
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