CA-IDMS 16.0 Performance and Non-Stop Enhancements

1
CA-IDMS 16.0Performance and Non-Stop Enhancement
s

• AUI meeting in France
• 27. November 2006
• Manfred Höfer, CA
• Prinicipal Support Engineer

2
Release 16.0

• File Cache in Memory
• Parallel Access Volume Exploitation
• Dynamic System Trace Control
• Varying Program Attributes
• Short-on-Storage Notification
• Journal and Recovery
• 16.2 High Performance Storage Protect

3
64-bit Exploitation

• Terminology
• The line 16 MB limit
• The bar 2 GB limit
• Z-storage Virtual storage above the bar
  2 GB 16 EB (Exabyte)
• - XA-storage. Virtual storage below the bar
  and above the line
• 16 MB 2 GB

4
64-bit Exploitation

• File caching in 64-bit storage

IDMS - CV or Local

• On a read
• look in cache
• if found, move to buffer
• if not found, read from file, copy to cache
• On a write
• copy to cache
• write to file

64-bit
Cache
31-bit
Buffer
5
Dataspace/Memory Cache 16.0

• The MEMORY CACHE clause replaces the use of the
  DATASPACE clause.
• DATASPACE clause is still accepted for upward
  compatibility, but is no longer generated on
  displays.
• The choice of whether to cache a file in memory
  or in a dataspace is determined at runtime based
  on the operating system
• In a z/OS 1.2 or later environment, files are
  cached in Z-storage.
• In earlier releases of the operating system
  files are cached in dataspaces.

6
Memory Cache

• - Insufficient storage for memory cache
• If MEMORY CACHE YES is specified and not enough
  Z-storage is available to cache a file in
  memory, processing continues depending on the
  DMCL-wide MEMORY CACHE clause
• LOCATION ANYWHERE
• dataspace storage is acquired
• LOCATION 64 BIT ONLY
• memory caching fails
• Dynamically changing memory cache specification
  
• The MEMORY CACHE specification for a file can be
  changed dynamically with the DCMT VARY FILE
  command.

7
PAV Exploitation
Advantage CA-IDMS PAV Exploitation
Job 1
File 1
Job 2
File 2

• Concurrent I/Os per file
• Single I/O per track

8
Dynamic System Trace Control

• New DCMT commands
• DCMT Display SYSTRace
• DCMT Vary SYSTRace ON ENTriesnnnnn
• DCMT Vary SYSTRace OFF
• DCMT Display DBTRace
• DCMT Vary DBTRace ON ENTriesnnnnn
• DCMT Vary DBTRace OFF

9
Varying Program Attributes

• Enhanced VARY PROGRAM support
• DCMT Vary PROgram xxxx DEFine
• LANguage ADSoCOBol
• TYPe MAPDIAlogPROgram
• MPMode ANYSYStem
• . . .
• RESIDENT cannot be changed
• Disable program to change language or type

10
Short-On-Storage Notification

• New message written to console if SOS
• DC015007 Pool 01 SOS condition 02
• Condition
• 0 remaining storage is less than cushion
  (SOS)
• 1 not enough contiguous storage available,
  request failed
• Duplicate messages suppressed
• (No more than 1 per minute)

11
Journaling and Recovery

• Faster recovery for long-running transactions
• New SYSGEN and DCMT options force an ENDJ instead
  of a COMT when a COMMIT is issued
• Less data has to be examined to locate the start
  of recovery unit
• Reduced journal writes
• JOURNAL TRANSACTION LEVEL extended to journal
  writes caused because updated pages are forced
  from the buffer

12
Journal Buffer Size (cont.)

• DCMT DISPLAY BUFFER
• - Journal Buffer - Size In-Use Waits
  DB Ckpt
• JNL_BUFFER 2932 80
  0 540 1365
• 
  of Recoveries I/O's in Buffer
• 
  3 6
  1

of buffer waits If gt 0, increase buffer size
recovery I/Os If large, increase buffer size
13
Journal Transaction Level

• Enables deferring journal write until block is
  full
• Fewer journal blocks written
• Fewer journal I/Os
• Better journal file utilization
• While of update transactions exceeds journal
  transaction level
• CV defers write of journal block until it fills

14
Journal Transaction Level (cont.)

• Journal transaction level should be
• 0 (no deferral occurs)
• Greater than 3
• If too large...no benefit
• Monitor ARCHIVE JOURNAL report

15
Journal Full Cushion

• Prevents system from hanging due to full journals
• If available space less than cushion
• Only checkpoint records can be written to journal
• Other writers display message and wait
• Allows administrator to cancel offending task
• Then issue DCMT VARY JOURNAL
• Implemented as a 15.0 APAR

16
Release 16.0

• File Cache in Memory
• Parallel Access Volume Exploitation
• Dynamic System Trace Control
• Varying Program Attributes
• Short-on-Storage Notification
• Journal and Recovery
• 16.2 High Performance Storage Protect

17
High Performance Storage Protect

• With the introduction of the z-architecture
  machines, the cost of IDMS storage protection
  increased dramatically.
• r16 SP2, introduces an alternate way to do
  storage protection that has very little (if any)
  performance impact.
• The High Performance Storage Protect feature
  makes no attempt to protect the non-reentrant
  user programs or users storage from each other.

18
High Performance Storage Protect (cont.)

• This feature makes use of the unique behavior of
  storage protect key 9 any program can write in
  key 9 storage. Programs running in key 9 can
  only write in key 9 storage.
• At startup, IDMS swaps the non-reentrant program
  pool and any storage pool supporting user storage
  to key 9.
• When control is given to a user program, the PSW
  key is swapped to key 9 and swapped back upon
  returning.

19
High Performance Storage Protect (cont.)

• It is expected that this feature will be used on
  production IDMS systems.
• The traditional IDMS storage protect feature is
  still available and will typically still be used
  on test systems.
• You can not use both the traditional and the high
  performance storage protect features at the same
  time, the new high performance storage protect
  feature takes precedence.

20
High Performance Storage Protect (cont.)

• To enable, the DBA must employ key 9 and
  segregate all user-oriented storage from IDMS
  system storage.
• To use the traditional storage protect feature,
  the system must be generated to use a key other
  than key 9.

21
High Performance Storage Protect (cont.)

• Storage Pool Definitions
• Range 128 to 254
• Range 1 to 127
• Storage types User, User Kept, Shared, and
  Shared Kept can be together but must be defined
  to secondary storage pools segregated from
  Database or Terminal type storage.
• SYSGEN storage protect key is 9
• Msg DC004001 at startup if HPSPO is not possible

22
High Performance Storage Protect (cont.)

• With apar QO83615 you can see with DCPROFIL and
  with DCMT D ALL STO if HPSPO is enabled
• DCPROFIL
• SYSTEM STORAGE PROTECTED YES
• HPSPO ENABLED YES
• DCMT D ALL STORAGE POOLS
  
• POOL ADDRESS SIZE CUSHION INUSE HWM
  TIMES PFIX CONTAINS
• 
  SOS TYPES
• 0 00288000 1000K 8K 60K
  60K 0 NO SY,TR,DB
• 1 00382000 1000K 52K 44K
  52K 0 NO SH,SK,US,UK
• 128 154E2000 2000K 100K 148K
  164K 0 NO TR,DB
• 129 156D6000 9000K 100K 1324K
  1336K 0 NO SH,SK,US,UK
• 255 15FA0000 4000K 0K 296K
  312K 0 NO SY
• High Performance Storage Protection Option
  Enabled

23
Comparing old and new storage protection
Protection is set for system and
program STANDARD SP When switching from User
to System Mode or from System to User Mode, IDMS
must run the task's resource chains and issue
SVCs to switch stg key for all of that task's
pages in memory as well as switching the stg key
in the PSW.
HPSPO (alternate key is 9)
Since the entire non-reentrant stg pool and all
stg pools that contain the user stg types will
already be set to the alt key 9, IDMS only has to
switch the PSW stg key.

24
Release 16.0

• File Cache in Memory
• Parallel Access Volume Exploitation
• Dynamic System Trace Control
• Varying Program Attributes
• Short-on-Storage Notification
• Journal and Recovery
• 16.2 High Performance Storage Protect

25

• QUESTIONS ?