New in this release

On the welcome page of the DB2(R) Information Center you will find a link to the list of new features added in this release. You can see the latest version of the DB2 Information Center through the IBM(R) Web site at http://publib.boulder.ibm.com/infocenter/db2help/index.jsp

The latest version of the DB2 Information Center can also be installed locally from the DB2 Information Center CD.

In addition to the new features listed in the DB2 Information Center, the following new features have also been added:

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New configuration parameters for log file allocation, removal, and 7archiving

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Two new configuration parameters, log archive method 1 (LOGARCHMETH1) and 7log archive method 2 (LOGARCHMETH2), have been added to handle log file allocation 7and removal. These parameters cause the database manager to archive log files 7to a location that is not in the active log path. If both of these parameters 7are specified, each log file is archived twice. This means that you will have 7two copies of archived log files in two different locations. These two new 7configuration parameters replace the user exit (USEREXIT) and log retain enable 7(LOGRETAIN) configuration parameters, which are still available, but should 7be used for back level compatibility only.

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Three other new configuration parameters, ARCHRETRYDELAY, NUMARCHRETRY, 7and FAILARCHPATH, have been added so that you can better tune log archiving 7to meet your needs. If an error occurs when log files are being archived, 7archiving is suspended for the amount of time specified by the ARCHRETRYDELAY 7database configuration parameter. You can use the NUMARCHRETRY database configuration 7parameter to specify the number of times that DB2 UDB is to try archiving 7 a log file to the primary or secondary archive directory. After the specified 7number of attempts have been made, DB2 UDB tries to archive log files to the 7failover directory, specified by the FAILARCHPATH database configuration parameter.

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Database shared memory region augmented at activation time

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At database activation time, DB2 UDB automatically augments the database 7shared memory region with an overflow buffer. The buffer is used to satisfy 7peak memory requirements for any heap in the database shared memory region 7whenever a heap exceeds its configured size. If a heap exceeds its configured 7size, the data area is expanded as needed until the entire overflow memory 7area in the database shared memory region is used.

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Query Patroller enhancements

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In addition to the existing supported platforms, DB2 UDB Version 8.2 introduces 764-bit support for the DB2 Query Patroller(TM) server on the following platforms:

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The benefits of 64-bit coverage include more address space for code, 7variables, shared memory, and buffer pools.

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7DB2 UDB Workgroup Server Edition and DB2 UDB Workgroup Server 7Unlimited Edition support DB2 Query Patroller 7

DB2 Query Patroller server can now be installed on top of the following 7DB2 products:

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KEEP UPDATE LOCKS phrase added

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A lock type can be specified for queries that perform updates. This change 7to a query involving cursors allows FOR UPDATE cursors to take advantage 7of row blocking. In addition, Repeatable Read (RR) or Read Stability (RS) 7can be selected when querying a read-only results table so that positioned 7cursor updates will succeed. The isolation-clause and lock-request-clause 7cannot be used in a subselect, SQL function, SQL method, or trigger.

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Formatting trap files (Windows)

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A new tool, db2xprt.exe, is available to let you format trap files (*.TRP). 7This tool formats DB2 UDB's binary trap files into a human readable ASCII 7file. Trap files are located in the instance directory (DB2INSTPROF) by default 7or in the diagnostic data directory path if the DIAGPATH database manager 7configuration parameter is set.

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7Authorization 7

You must have access to the DIAGPATH directory.

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7Command syntax 7

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Read syntax diagramSkip visual syntax diagram7>>-db2xprt--+----------+--+----+--+----+--infile--+---------+--><
7            +-/p--path-+  '-/m-'  '-/n-'          '-outfile-'
7            '-/v-------'
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7
7
7Command parameters 7

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/p path
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A semicolon (;) separated path that points to the location 7or locations where the binary files and PDB files are located. 7
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/v
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Displays version information. 7
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/m
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Formats a memory dump along with the rest of the trap file. 7
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/n
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Format data without regard to line number information. 7
7
infile
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Specifies the input file. 7
7
outfile
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Specifies the output file. 7
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Setting memory pinning is now available (Linux)

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Memory pinning is now available as an option for DB2 UDB Version 8.2 on 7all Linux architectures. With memory pinning enabled, the database shared 7 memory set is kept in RAM and is not swapped out. This strategy results 7in better use of memory, and it keeps more memory available for other uses.

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7Procedure 7

To set memory pinning:

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    7
  1. Ensure your Linux distribution provides the libcap.so library
    2. 7
  2. Set the db2set variable DB2_PINNED_BP to YES
    3. 7
  3. Stop and start the database engine

The ipcs -m command shows shared memory segments 7with a LOCKED status when any agent is connected to a database in an instance 7that has been started with this option.

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Defining resource policies (AIX, Linux)

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DB2 UDB now supports precise configuration of DB2 UDB use of some operating 7system resources. For example, you can pin each engine EDU to a single logical 7processor. Such advanced configurations can improve performance in some scenarios. 7However, these configurations should be attempted only by advanced users who 7are knowledgeable about their operating environment and its workload. Misconfiguration 7can result in degraded performance.

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A resource policy is defined to describe how DB2 UDB interacts with the 7operating system. The resource policy typically limits what resources DB2 7UDB uses, or it contains rules for assigning specific operating system resources 7to specific DB2 UDB objects. The extent of resource control varies depending 7on the operating system.

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Table 1. Resource control by platform
Platform Overview of support
Linux Restrict a DB2 UDB instance to use only a subset of 7logical processors on the system.
AIX(R) 5.2 7
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  • Restrict a DB2 UDB instance to use only a subset of logical processors 7on the system
    • 7
  • Define how DB2 UDB objects such as EDUs, buffer pools, and page cleaners 7are bound to particular resource sets
    • 7
  • Configure resource set use at the database level
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7Defining a resource policy 7

The DB2_RESOURCE_POLICY registry variable is used to define a resource 7policy. This variable can be set to the path of a well formed configuration 7file.

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You might experience several types of failure when configuring a resource 7policy:

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Any error in configuring a resource policy results in db2start failing.

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The operating system requirements for resource policy support are described 7in the following table.

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Table 2. Operating system requirements for resource policy support
Platform Overview of support
Linux 7
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  • SUSE Linux Enterprise Server 8 (or 9) or RedHat Enterprise Linux 3
    • 7
  • SMP hardware
AIX 5.2 7
    7
  • AIX 5.2 running on NUMA capable hardware
    • 7
  • The instance owner is granted the CAP_NUMA_ATTACH AIX capability
    • 7
  • Set the DB2ENVLIST registry variable to "MEMORY_AFFINITY DATA_SEG_SPECIAL"
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  • Set 'MEMORY_AFFINITY=MCM' and 'DATA_SET_SPECIAL=Y'' 7in your db2profile.
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  • The vmo option memory_affinity must be set 7to 1, and the vmo option num_spec_dataseg must 7be set to at least the maximum number of DB2 agents.
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7Each DB2 process is bound to a single processor 7

The following sample configuration file illustrates one-to-one 7processor-to-processor binding on AIX and Linux.

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<RESOURCE_POLICY>
7   <GLOBAL_RESOURCE_POLICY>
7   <METHOD>CPU</METHOD>
7      <RESOURCE_BINDING>
7         <RESOURCE>0</RESOURCE>
7      </RESOURCE_BINDING>
7      <RESOURCE_BINDING>
7         <RESOURCE>1</RESOURCE>
7      </RESOURCE_BINDING>
7   </GLOBAL_RESOURCE_POLICY>
7</RESOURCE_POLICY>

Each DB2 UDB engine process will be bound to either processor 0 or processor 71. Processor binding of engine processes to processors identified in the policy 7occurs in a circular round-robin fashion. This policy assumes that the system 7consists of at least 2 logical processors. Processors are identified by a 7number from 0 to (n-1) where n is the number of processors on the system.

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Note:
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This binding mechanism should not be used to restrict the 7processors available for use by a DB2 UDB instance. Instead, consider using 7the various operating system facilities, such as WLM on AIX, for workload 7management.
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7NUMA exploitation 7

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Topology-based configuration
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A topology-based configuration describes the precise binding of DB2 7UDB objects to resource manager resource sets. 7
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The following is a sample file for topology-based configuration:

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<RESOURCE_POLICY>
7   <DATABASE_RESOURCE_POLICY>
7   <DBNAME>MYDB</DBNAME>
7   <METHOD>RSET</METHOD>
7   <RESOURCE_BINDING>
7      <RESOURCE>sys/node.02.00000</RESOURCE>
7      <DBMEM_PERCENTAGE>25.0</DBMEM_PERCENTAGE>
7      <SERVICE_NAME>svnm0</SERVICE_NAME>
7      <BUFFERPOOL_BINDING>
7         <NUM_CLEANERS>3</NUM_CLEANERS>
7         <BUFFERPOOL_ID>4</BUFFERPOOL_ID>
7         <BUFFERPOOL_ID>8</BUFFERPOOL_ID>
7      </BUFFERPOOL_BINDING>
7   </RESOURCE_BINDING>
7   <RESOURCE_BINDING>
7      <RESOURCE>sys/node.02.00001</RESOURCE>
7      <DBMEM_PERCENTAGE>50.0</DBMEM_PERCENTAGE>
7      <SERVICE_NAME>svnm1</SERVICE_NAME>
7      <BUFFERPOOL_BINDING>
7         <NUM_CLEANERS>5</NUM_CLEANERS>
7         <BUFFERPOOL_ID>12</BUFFERPOOL_ID>
7         <BUFFERPOOL_ID>13</BUFFERPOOL_ID>
7      </BUFFERPOOL_BINDING>
7      <BUFFER_POOL_BINDING>
7         <NUM_CLEANERS>2</NUM_CLEANERS>
7         <BUFFERPOOL_ID>32</BUFFERPOOL_ID>
7      </BUFFERPOOL_BINDING>  
7   </RESOURCE_BINDING>
7   </DATABASE_RESOURCE_POLICY>
7</RESOURCE_POLICY>
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The following points provide analysis of the preceding sample file:

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